mainly link-relax changes

[external/binutils.git] / gas / config / tc-i960.c

/* tc-i960.c - All the i80960-specific stuff
   Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
   
   This file is part of GAS.
   
   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
   
   GAS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* See comment on md_parse_option for 80960-specific invocation options. */

/******************************************************************************
 * i80690 NOTE!!!:
 *      Header, symbol, and relocation info will be used on the host machine
 *      only -- only executable code is actually downloaded to the i80960.
 *      Therefore, leave all such information in host byte order.
 *
 *      (That's a slight lie -- we DO download some header information, but
 *      the downloader converts the file format and corrects the byte-ordering
 *      of the relevant fields while doing so.)
 *
 ***************************************************************************** */

/* There are 4 different lengths of (potentially) symbol-based displacements
 * in the 80960 instruction set, each of which could require address fix-ups
 * and (in the case of external symbols) emission of relocation directives:
 *
 * 32-bit (MEMB)
 *      This is a standard length for the base assembler and requires no
 *      special action.
 *
 * 13-bit (COBR)
 *      This is a non-standard length, but the base assembler has a hook for
 *      bit field address fixups:  the fixS structure can point to a descriptor
 *      of the field, in which case our md_number_to_field() routine gets called
 *      to process it.
 *
 *      I made the hook a little cleaner by having fix_new() (in the base
 *      assembler) return a pointer to the fixS in question.  And I made it a
 *      little simpler by storing the field size (in this case 13) instead of
 *      of a pointer to another structure:  80960 displacements are ALWAYS
 *      stored in the low-order bits of a 4-byte word.
 *
 *      Since the target of a COBR cannot be external, no relocation directives
 *      for this size displacement have to be generated.  But the base assembler
 *      had to be modified to issue error messages if the symbol did turn out
 *      to be external.
 *
 * 24-bit (CTRL)
 *      Fixups are handled as for the 13-bit case (except that 24 is stored
 *      in the fixS).
 *
 *      The relocation directive generated is the same as that for the 32-bit
 *      displacement, except that it's PC-relative (the 32-bit displacement
 *      never is).   The i80960 version of the linker needs a mod to
 *      distinguish and handle the 24-bit case.
 *
 * 12-bit (MEMA)
 *      MEMA formats are always promoted to MEMB (32-bit) if the displacement
 *      is based on a symbol, because it could be relocated at link time.
 *      The only time we use the 12-bit format is if an absolute value of
 *      less than 4096 is specified, in which case we need neither a fixup nor
 *      a relocation directive.
 */

#include <stdio.h>
#include <ctype.h>

#include "as.h"

#include "obstack.h"

#include "opcode/i960.h"

extern char *input_line_pointer;
extern struct hash_control *po_hash;
extern char *next_object_file_charP;

#ifdef OBJ_COFF
int md_reloc_size = sizeof(struct reloc);
#else /* OBJ_COFF */
int md_reloc_size = sizeof(struct relocation_info);
#endif /* OBJ_COFF */

/***************************
 *  Local i80960 routines  *
 ************************** */

static void     brcnt_emit();   /* Emit branch-prediction instrumentation code */
static char *   brlab_next();   /* Return next branch local label */
void    brtab_emit();   /* Emit br-predict instrumentation table */
static void     cobr_fmt();     /* Generate COBR instruction */
static void     ctrl_fmt();     /* Generate CTRL instruction */
static char *   emit();         /* Emit (internally) binary */
static int get_args();  /* Break arguments out of comma-separated list */
static void     get_cdisp();    /* Handle COBR or CTRL displacement */
static char *   get_ispec();    /* Find index specification string */
static int get_regnum();        /* Translate text to register number */
static int i_scan();    /* Lexical scan of instruction source */
static void     mem_fmt();      /* Generate MEMA or MEMB instruction */
static void     mema_to_memb(); /* Convert MEMA instruction to MEMB format */
static segT     parse_expr();   /* Parse an expression */
static int parse_ldconst();/* Parse and replace a 'ldconst' pseudo-op */
static void     parse_memop();  /* Parse a memory operand */
static void     parse_po();     /* Parse machine-dependent pseudo-op */
static void     parse_regop();  /* Parse a register operand */
static void     reg_fmt();      /* Generate a REG format instruction */
void    reloc_callj();  /* Relocate a 'callj' instruction */
static void     relax_cobr();   /* "De-optimize" cobr into compare/branch */
static void     s_leafproc();   /* Process '.leafproc' pseudo-op */
static void     s_sysproc();    /* Process '.sysproc' pseudo-op */
static int shift_ok();  /* Will a 'shlo' substiture for a 'ldconst'? */
static void     syntax();       /* Give syntax error */
static int targ_has_sfr();      /* Target chip supports spec-func register? */
static int targ_has_iclass();/* Target chip supports instruction set? */
/* static void  unlink_sym(); */        /* Remove a symbol from the symbol list */

/* See md_parse_option() for meanings of these options */
static char norelax;            /* True if -norelax switch seen */
static char instrument_branches; /* True if -b switch seen */

/* Characters that always start a comment.
 * If the pre-processor is disabled, these aren't very useful.
 */
char comment_chars[] = "#";

/* Characters that only start a comment at the beginning of
 * a line.  If the line seems to have the form '# 123 filename'
 * .line and .file directives will appear in the pre-processed output.
 *
 * Note that input_file.c hand checks for '#' at the beginning of the
 * first line of the input file.  This is because the compiler outputs
 * #NO_APP at the beginning of its output.
 */

/* Also note that comments started like this one will always work. */

char line_comment_chars[] = "";

/* Chars that can be used to separate mant from exp in floating point nums */
char EXP_CHARS[] = "eE";

/* Chars that mean this number is a floating point constant,
 * as in 0f12.456 or 0d1.2345e12
 */
char FLT_CHARS[] = "fFdDtT";


/* Table used by base assembler to relax addresses based on varying length
 * instructions.  The fields are:
 *   1) most positive reach of this state,
 *   2) most negative reach of this state,
 *   3) how many bytes this mode will add to the size of the current frag
 *   4) which index into the table to try if we can't fit into this one.
 *
 * For i80960, the only application is the (de-)optimization of cobr
 * instructions into separate compare and branch instructions when a 13-bit
 * displacement won't hack it.
 */
const relax_typeS
    md_relax_table[] = {
            {0,         0,        0,0}, /* State 0 => no more relaxation possible */
            {4088,      -4096,    0,2}, /* State 1: conditional branch (cobr) */
            {0x800000-8,-0x800000,4,0}, /* State 2: compare (reg) & branch (ctrl) */
    };


/* These are the machine dependent pseudo-ops.
 *
 * This table describes all the machine specific pseudo-ops the assembler
 * has to support.  The fields are:
 *      pseudo-op name without dot
 *      function to call to execute this pseudo-op
 *      integer arg to pass to the function
 */
#define S_LEAFPROC      1
#define S_SYSPROC       2

const pseudo_typeS md_pseudo_table[] = {
  { "bss",      s_lcomm,        1 },
  { "extended", float_cons,     't' },
  { "leafproc", parse_po,       S_LEAFPROC },
  { "sysproc",  parse_po,       S_SYSPROC },

  { "word",     cons,           4 },
  { "quad",     big_cons,       16 },

  { 0,          0,              0 }
};
\f
/* Macros to extract info from an 'expressionS' structure 'e' */
#define adds(e) e.X_add_symbol
#define subs(e) e.X_subtract_symbol
#define offs(e) e.X_add_number
#define segs(e) e.X_seg
    
    
    /* Branch-prediction bits for CTRL/COBR format opcodes */
#define BP_MASK         0x00000002  /* Mask for branch-prediction bit */
#define BP_TAKEN        0x00000000  /* Value to OR in to predict branch */
#define BP_NOT_TAKEN    0x00000002  /* Value to OR in to predict no branch */
    
    
    /* Some instruction opcodes that we need explicitly */
#define BE      0x12000000
#define BG      0x11000000
#define BGE     0x13000000
#define BL      0x14000000
#define BLE     0x16000000
#define BNE     0x15000000
#define BNO     0x10000000
#define BO      0x17000000
#define CHKBIT  0x5a002700
#define CMPI    0x5a002080
#define CMPO    0x5a002000
    
#define B       0x08000000
#define BAL     0x0b000000
#define CALL    0x09000000
#define CALLS   0x66003800
#define RET     0x0a000000
    
    
    /* These masks are used to build up a set of MEMB mode bits. */
#define A_BIT           0x0400
#define I_BIT           0x0800
#define MEMB_BIT        0x1000
#define D_BIT           0x2000
    
    
    /* Mask for the only mode bit in a MEMA instruction (if set, abase reg is used) */
#define MEMA_ABASE      0x2000
    
    /* Info from which a MEMA or MEMB format instruction can be generated */
    typedef struct {
            long opcode;        /* (First) 32 bits of instruction */
            int disp;   /* 0-(none), 12- or, 32-bit displacement needed */
            char *e;    /* The expression in the source instruction from
                         *      which the displacement should be determined
                         */
    } memS;


/* The two pieces of info we need to generate a register operand */
struct regop {
        int mode;       /* 0 =>local/global/spec reg; 1=> literal or fp reg */
        int special;    /* 0 =>not a sfr;  1=> is a sfr (not valid w/mode=0) */
        int n;          /* Register number or literal value */
};


/* Number and assembler mnemonic for all registers that can appear in operands */
static struct {
        char *reg_name;
        int reg_num;
} regnames[] = {
        { "pfp",  0 }, { "sp",   1 }, { "rip",  2 }, { "r3",   3 },
        { "r4",   4 }, { "r5",   5 }, { "r6",   6 }, { "r7",   7 },
        { "r8",   8 }, { "r9",   9 }, { "r10", 10 }, { "r11", 11 },
        { "r12", 12 }, { "r13", 13 }, { "r14", 14 }, { "r15", 15 },
        { "g0",  16 }, { "g1",  17 }, { "g2",  18 }, { "g3",  19 },
        { "g4",  20 }, { "g5",  21 }, { "g6",  22 }, { "g7",  23 },
        { "g8",  24 }, { "g9",  25 }, { "g10", 26 }, { "g11", 27 },
        { "g12", 28 }, { "g13", 29 }, { "g14", 30 }, { "fp",  31 },
        
        /* Numbers for special-function registers are for assembler internal
         * use only: they are scaled back to range [0-31] for binary output.
         */
#       define SF0      32
        
        { "sf0", 32 }, { "sf1", 33 }, { "sf2", 34 }, { "sf3", 35 },
        { "sf4", 36 }, { "sf5", 37 }, { "sf6", 38 }, { "sf7", 39 },
        { "sf8", 40 }, { "sf9", 41 }, { "sf10",42 }, { "sf11",43 },
        { "sf12",44 }, { "sf13",45 }, { "sf14",46 }, { "sf15",47 },
        { "sf16",48 }, { "sf17",49 }, { "sf18",50 }, { "sf19",51 },
        { "sf20",52 }, { "sf21",53 }, { "sf22",54 }, { "sf23",55 },
        { "sf24",56 }, { "sf25",57 }, { "sf26",58 }, { "sf27",59 },
        { "sf28",60 }, { "sf29",61 }, { "sf30",62 }, { "sf31",63 },
        
        /* Numbers for floating point registers are for assembler internal use
         * only: they are scaled back to [0-3] for binary output.
         */
#       define FP0      64
        
        { "fp0", 64 }, { "fp1", 65 }, { "fp2", 66 }, { "fp3", 67 },
        
        { NULL,  0 },           /* END OF LIST */
};

#define IS_RG_REG(n)    ((0 <= (n)) && ((n) < SF0))
#define IS_SF_REG(n)    ((SF0 <= (n)) && ((n) < FP0))
#define IS_FP_REG(n)    ((n) >= FP0)

/* Number and assembler mnemonic for all registers that can appear as 'abase'
 * (indirect addressing) registers.
 */
static struct {
        char *areg_name;
        int areg_num;
} aregs[] = {
        { "(pfp)",  0 }, { "(sp)",   1 }, { "(rip)",  2 }, { "(r3)",   3 },
        { "(r4)",   4 }, { "(r5)",   5 }, { "(r6)",   6 }, { "(r7)",   7 },
        { "(r8)",   8 }, { "(r9)",   9 }, { "(r10)", 10 }, { "(r11)", 11 },
        { "(r12)", 12 }, { "(r13)", 13 }, { "(r14)", 14 }, { "(r15)", 15 },
        { "(g0)",  16 }, { "(g1)",  17 }, { "(g2)",  18 }, { "(g3)",  19 },
        { "(g4)",  20 }, { "(g5)",  21 }, { "(g6)",  22 }, { "(g7)",  23 },
        { "(g8)",  24 }, { "(g9)",  25 }, { "(g10)", 26 }, { "(g11)", 27 },
        { "(g12)", 28 }, { "(g13)", 29 }, { "(g14)", 30 }, { "(fp)",  31 },
        
#       define IPREL    32
        /* for assembler internal use only: this number never appears in binary
         * output.
         */
        { "(ip)", IPREL },
        
        { NULL,  0 },           /* END OF LIST */
};


/* Hash tables */
static struct hash_control *op_hash = NULL;     /* Opcode mnemonics */
static struct hash_control *reg_hash = NULL;    /* Register name hash table */
static struct hash_control *areg_hash = NULL;   /* Abase register hash table */


/* Architecture for which we are assembling */
#define ARCH_ANY        0       /* Default: no architecture checking done */
#define ARCH_KA         1
#define ARCH_KB         2
#define ARCH_MC         3
#define ARCH_CA         4
int architecture = ARCH_ANY;    /* Architecture requested on invocation line */
int iclasses_seen = 0;          /* OR of instruction classes (I_* constants)
                                 *      for which we've actually assembled
                                 *      instructions.
                                 */


/* BRANCH-PREDICTION INSTRUMENTATION
 *
 *      The following supports generation of branch-prediction instrumentation
 *      (turned on by -b switch).  The instrumentation collects counts
 *      of branches taken/not-taken for later input to a utility that will
 *      set the branch prediction bits of the instructions in accordance with
 *      the behavior observed.  (Note that the KX series does not have
 *      brach-prediction.)
 *
 *      The instrumentation consists of:
 *
 *      (1) before and after each conditional branch, a call to an external
 *          routine that increments and steps over an inline counter.  The
 *          counter itself, initialized to 0, immediately follows the call
 *          instruction.  For each branch, the counter following the branch
 *          is the number of times the branch was not taken, and the difference
 *          between the counters is the number of times it was taken.  An
 *          example of an instrumented conditional branch:
 *
 *                              call    BR_CNT_FUNC
 *                              .word   0
 *              LBRANCH23:      be      label
 *                              call    BR_CNT_FUNC
 *                              .word   0
 *
 *      (2) a table of pointers to the instrumented branches, so that an
 *          external postprocessing routine can locate all of the counters.
 *          the table begins with a 2-word header: a pointer to the next in
 *          a linked list of such tables (initialized to 0);  and a count
 *          of the number of entries in the table (exclusive of the header.
 *
 *          Note that input source code is expected to already contain calls
 *          an external routine that will link the branch local table into a
 *          list of such tables.
 */

static int br_cnt = 0;          /* Number of branches instrumented so far.
                                 * Also used to generate unique local labels
                                 * for each instrumented branch
                                 */

#define BR_LABEL_BASE   "LBRANCH"
/* Basename of local labels on instrumented
 * branches, to avoid conflict with compiler-
 * generated local labels.
 */

#define BR_CNT_FUNC     "__inc_branch"
/* Name of the external routine that will
 * increment (and step over) an inline counter.
 */

#define BR_TAB_NAME     "__BRANCH_TABLE__"
/* Name of the table of pointers to branches.
 * A local (i.e., non-external) symbol.
 */
\f
/*****************************************************************************
 * md_begin:  One-time initialization.
 *
 *      Set up hash tables.
 *
 **************************************************************************** */
void
    md_begin()
{
        int i;                          /* Loop counter */
        const struct i960_opcode *oP; /* Pointer into opcode table */
        char *retval;                   /* Value returned by hash functions */
        
        if (((op_hash = hash_new()) == 0)
            || ((reg_hash = hash_new()) == 0)
            || ((areg_hash = hash_new()) == 0)) {
                as_fatal("virtual memory exceeded");
        }
        
        retval = "";    /* For some reason, the base assembler uses an empty
                         * string for "no error message", instead of a NULL
                         * pointer.
                         */
        
        for (oP=i960_opcodes; oP->name && !*retval; oP++) {
                retval = hash_insert(op_hash, oP->name, oP);
        }
        
        for (i=0; regnames[i].reg_name && !*retval; i++) {
                retval = hash_insert(reg_hash, regnames[i].reg_name,
                                     &regnames[i].reg_num);
        }
        
        for (i=0; aregs[i].areg_name && !*retval; i++){
                retval = hash_insert(areg_hash, aregs[i].areg_name,
                                     &aregs[i].areg_num);
        }
        
        if (*retval) {
                as_fatal("Hashing returned \"%s\".", retval);
        }
} /* md_begin() */

/*****************************************************************************
 * md_end:  One-time final cleanup
 *
 *      None necessary
 *
 **************************************************************************** */
void
    md_end()
{
}

/*****************************************************************************
 * md_assemble:  Assemble an instruction
 *
 * Assumptions about the passed-in text:
 *      - all comments, labels removed
 *      - text is an instruction
 *      - all white space compressed to single blanks
 *      - all character constants have been replaced with decimal
 *
 **************************************************************************** */
void
    md_assemble(textP)
char *textP;    /* Source text of instruction */
{
        char *args[4];  /* Parsed instruction text, containing NO whitespace:
                         *      arg[0]->opcode mnemonic
                         *      arg[1-3]->operands, with char constants
                         *                      replaced by decimal numbers
                         */
        int n_ops;      /* Number of instruction operands */
        int callx;
        struct i960_opcode *oP;
        /* Pointer to instruction description */
        int branch_predict;
        /* TRUE iff opcode mnemonic included branch-prediction
         *      suffix (".f" or ".t")
         */
        long bp_bits;   /* Setting of branch-prediction bit(s) to be OR'd
                         *      into instruction opcode of CTRL/COBR format
                         *      instructions.
                         */
        int n;          /* Offset of last character in opcode mnemonic */
        
        static const char bp_error_msg[] = "branch prediction invalid on this opcode";
        
        
        /* Parse instruction into opcode and operands */
        memset(args, '\0', sizeof(args));
        n_ops = i_scan(textP, args);
        if (n_ops == -1){
                return;         /* Error message already issued */
        }
        
        /* Do "macro substitution" (sort of) on 'ldconst' pseudo-instruction */
        if (!strcmp(args[0],"ldconst")){
                n_ops = parse_ldconst(args);
                if (n_ops == -1){
                        return;
                }
        }


        
        /* Check for branch-prediction suffix on opcode mnemonic, strip it off */
        n = strlen(args[0]) - 1;
        branch_predict = 0;
        bp_bits = 0;
        if (args[0][n-1] == '.' && (args[0][n] == 't' || args[0][n] == 'f')){
                /* We could check here to see if the target architecture
                 * supports branch prediction, but why bother?  The bit
                 * will just be ignored by processors that don't use it.
                 */
                branch_predict = 1;
                bp_bits = (args[0][n] == 't') ? BP_TAKEN : BP_NOT_TAKEN;
                args[0][n-1] = '\0';    /* Strip suffix from opcode mnemonic */
        }
        
        /* Look up opcode mnemonic in table and check number of operands.
         * Check that opcode is legal for the target architecture.
         * If all looks good, assemble instruction.
         */
        oP = (struct i960_opcode *) hash_find(op_hash, args[0]);
        if (!oP || !targ_has_iclass(oP->iclass)) {
                as_bad("invalid opcode, \"%s\".", args[0]);
                
        } else if (n_ops != oP->num_ops) {
                as_bad("improper number of operands.  expecting %d, got %d", oP->num_ops, n_ops);
                
        } else {
                switch (oP->format){
                case FBRA:
                case CTRL:
                        ctrl_fmt(args[1], oP->opcode | bp_bits, oP->num_ops);
                        if (oP->format == FBRA){
                                /* Now generate a 'bno' to same arg */
                                ctrl_fmt(args[1], BNO | bp_bits, 1);
                        }
                        break;
                case COBR:
                case COJ:
                        cobr_fmt(args, oP->opcode | bp_bits, oP);
                        break;
                case REG:
                        if (branch_predict){
                                as_warn(bp_error_msg);
                        }
                        reg_fmt(args, oP);
                        break;
                case MEM1:
                        if (args[0][0] == 'c' && args[0][1] == 'a') 
                        {
                          if (branch_predict)
                          {
                            as_warn(bp_error_msg);
                          }
                          mem_fmt(args, oP, 1);
                          break;
                        }
                case MEM2:
                case MEM4:
                case MEM8:
                case MEM12:
                case MEM16:
                        if (branch_predict){
                                as_warn(bp_error_msg);
                        }
                        mem_fmt(args, oP, 0);
                        break;
                case CALLJ:
                        if (branch_predict){
                                as_warn(bp_error_msg);
                        }
                        /* Output opcode & set up "fixup" (relocation);
                         * flag relocation as 'callj' type.
                         */
                        know(oP->num_ops == 1);
                        get_cdisp(args[1], "CTRL", oP->opcode, 24, 0, 1);
                        break;
                default:
                        BAD_CASE(oP->format);
                        break;
                }
        }
} /* md_assemble() */

/*****************************************************************************
 * md_number_to_chars:  convert a number to target byte order
 *
 **************************************************************************** */
void
    md_number_to_chars(buf, value, n)
char *buf;              /* Put output here */
long value;             /* The integer to be converted */
int n;          /* Number of bytes to output (significant bytes
                 *      in 'value')
                 */
{
        while (n--){
                *buf++ = value;
                value >>= 8;
        }
        
        /* XXX line number probably botched for this warning message. */
        if (value != 0 && value != -1){
                as_bad("Displacement too long for instruction field length.");
        }
        
        return;
} /* md_number_to_chars() */

/*****************************************************************************
 * md_chars_to_number:  convert from target byte order to host byte order.
 *
 **************************************************************************** */
int
    md_chars_to_number(val, n)
unsigned char *val;     /* Value in target byte order */
int n;          /* Number of bytes in the input */
{
        int retval;
        
        for (retval=0; n--;){
                retval <<= 8;
                retval |= val[n];
        }
        return retval;
}


#define MAX_LITTLENUMS  6
#define LNUM_SIZE       sizeof(LITTLENUM_TYPE)

/*****************************************************************************
 * md_atof:     convert ascii to floating point
 *
 * Turn a string at input_line_pointer into a floating point constant of type
 * 'type', and store the appropriate bytes at *litP.  The number of LITTLENUMS
 * emitted is returned at 'sizeP'.  An error message is returned, or a pointer
 * to an empty message if OK.
 *
 * Note we call the i386 floating point routine, rather than complicating
 * things with more files or symbolic links.
 *
 **************************************************************************** */
char * md_atof(type, litP, sizeP)
int type;
char *litP;
int *sizeP;
{
        LITTLENUM_TYPE words[MAX_LITTLENUMS];
        LITTLENUM_TYPE *wordP;
        int prec;
        char *t;
        char *atof_ieee();
        
        switch(type) {
        case 'f':
        case 'F':
                prec = 2;
                break;
                
        case 'd':
        case 'D':
                prec = 4;
                break;
                
        case 't':
        case 'T':
                prec = 5;
                type = 'x';     /* That's what atof_ieee() understands */
                break;
                
        default:
                *sizeP=0;
                return "Bad call to md_atof()";
        }
        
        t = atof_ieee(input_line_pointer, type, words);
        if (t){
                input_line_pointer = t;
        }
        
        *sizeP = prec * LNUM_SIZE;
        
        /* Output the LITTLENUMs in REVERSE order in accord with i80960
         * word-order.  (Dunno why atof_ieee doesn't do it in the right
         * order in the first place -- probably because it's a hack of
         * atof_m68k.)
         */
        
        for(wordP = words + prec - 1; prec--;){
                md_number_to_chars(litP, (long) (*wordP--), LNUM_SIZE);
                litP += sizeof(LITTLENUM_TYPE);
        }
        
        return "";      /* Someone should teach Dean about null pointers */
}


/*****************************************************************************
 * md_number_to_imm
 *
 **************************************************************************** */
void
    md_number_to_imm(buf, val, n)
char *buf;
long val;
int n;
{
        md_number_to_chars(buf, val, n);
}


/*****************************************************************************
 * md_number_to_disp
 *
 **************************************************************************** */
void
    md_number_to_disp(buf, val, n)
char *buf;
long val;
int n;
{
        md_number_to_chars(buf, val, n);
}

/*****************************************************************************
 * md_number_to_field:
 *
 *      Stick a value (an address fixup) into a bit field of
 *      previously-generated instruction.
 *
 **************************************************************************** */
void
    md_number_to_field(instrP, val, bfixP)
char *instrP;   /* Pointer to instruction to be fixed */
long val;               /* Address fixup value */
bit_fixS *bfixP;        /* Description of bit field to be fixed up */
{
        int numbits;    /* Length of bit field to be fixed */
        long instr;     /* 32-bit instruction to be fixed-up */
        long sign;      /* 0 or -1, according to sign bit of 'val' */
        
        /* Convert instruction back to host byte order
         */
        instr = md_chars_to_number(instrP, 4);
        
        /* Surprise! -- we stored the number of bits
         * to be modified rather than a pointer to a structure.
         */
        numbits = (int)bfixP;
        if (numbits == 1){
                /* This is a no-op, stuck here by reloc_callj() */
                return;
        }
        
        know ((numbits==13) || (numbits==24));
        
        /* Propagate sign bit of 'val' for the given number of bits.
         * Result should be all 0 or all 1
         */
        sign = val >> ((int)numbits - 1);
        if (((val < 0) && (sign != -1))
            ||   ((val > 0) && (sign != 0))){
                as_bad("Fixup of %d too large for field width of %d",
                       val, numbits);
        } else {
                /* Put bit field into instruction and write back in target
                 * byte order.
                 */
                val &= ~(-1 << (int)numbits);   /* Clear unused sign bits */
                instr |= val;
                md_number_to_chars(instrP, instr, 4);
        }
} /* md_number_to_field() */


/*****************************************************************************
 * md_parse_option
 *      Invocation line includes a switch not recognized by the base assembler.
 *      See if it's a processor-specific option.  For the 960, these are:
 *
 *      -norelax:
 *              Conditional branch instructions that require displacements
 *              greater than 13 bits (or that have external targets) should
 *              generate errors.  The default is to replace each such
 *              instruction with the corresponding compare (or chkbit) and
 *              branch instructions.  Note that the Intel "j" cobr directives
 *              are ALWAYS "de-optimized" in this way when necessary,
 *              regardless of the setting of this option.
 *
 *      -b:
 *              Add code to collect information about branches taken, for
 *              later optimization of branch prediction bits by a separate
 *              tool.  COBR and CNTL format instructions have branch
 *              prediction bits (in the CX architecture);  if "BR" represents
 *              an instruction in one of these classes, the following rep-
 *              resents the code generated by the assembler:
 *
 *                      call    <increment routine>
 *                      .word   0       # pre-counter
 *              Label:  BR
 *                      call    <increment routine>
 *                      .word   0       # post-counter
 *
 *              A table of all such "Labels" is also generated.
 *
 *
 *      -AKA, -AKB, -AKC, -ASA, -ASB, -AMC, -ACA:
 *              Select the 80960 architecture.  Instructions or features not
 *              supported by the selected architecture cause fatal errors.
 *              The default is to generate code for any instruction or feature
 *              that is supported by SOME version of the 960 (even if this
 *              means mixing architectures!).
 *
 **************************************************************************** */
int
    md_parse_option(argP, cntP, vecP)
char **argP;
int *cntP;
char ***vecP;
{
        char *p;
        struct tabentry { char *flag; int arch; };
        static struct tabentry arch_tab[] = {
                "KA", ARCH_KA,
                "KB", ARCH_KB,
                "SA", ARCH_KA,  /* Synonym for KA */
                "SB", ARCH_KB,  /* Synonym for KB */
                "KC", ARCH_MC,  /* Synonym for MC */
                "MC", ARCH_MC,
                "CA", ARCH_CA,
                NULL, 0
            };
        struct tabentry *tp;
        if (!strcmp(*argP,"linkrelax")){
                linkrelax = 1;
                flagseen ['L'] = 1;
        } else if (!strcmp(*argP,"norelax")){
                norelax = 1;
                
        } else if (**argP == 'b'){
                instrument_branches = 1;
                
        } else if (**argP == 'A'){
                p = (*argP) + 1;
                
                for (tp = arch_tab; tp->flag != NULL; tp++){
                        if (!strcmp(p,tp->flag)){
                                break;
                        }
                }
                
                if (tp->flag == NULL){
                        as_bad("unknown architecture: %s", p);
                } else {
                        architecture = tp->arch;
                }
        } else {
                /* Unknown option */
                (*argP)++;
                return 0;
        }
        **argP = '\0';  /* Done parsing this switch */
        return 1;
}

/*****************************************************************************
 * md_convert_frag:
 *      Called by base assembler after address relaxation is finished:  modify
 *      variable fragments according to how much relaxation was done.
 *
 *      If the fragment substate is still 1, a 13-bit displacement was enough
 *      to reach the symbol in question.  Set up an address fixup, but otherwise
 *      leave the cobr instruction alone.
 *
 *      If the fragment substate is 2, a 13-bit displacement was not enough.
 *      Replace the cobr with a two instructions (a compare and a branch).
 *
 **************************************************************************** */
void
    md_convert_frag(headers, fragP)
object_headers *headers;
fragS * fragP;
{
        fixS *fixP;     /* Structure describing needed address fix */
        
        switch (fragP->fr_subtype){
        case 1:
                /* LEAVE SINGLE COBR INSTRUCTION */
                fixP = fix_new(fragP,
                               fragP->fr_opcode-fragP->fr_literal,
                               4,
                               fragP->fr_symbol,
                               0,
                               fragP->fr_offset,
                               1,
                               0);
                
                fixP->fx_bit_fixP = (bit_fixS *) 13;    /* size of bit field */
                break;
        case 2:
                /* REPLACE COBR WITH COMPARE/BRANCH INSTRUCTIONS */
                relax_cobr(fragP);
                break;
        default:
                BAD_CASE(fragP->fr_subtype);
                break;
        }
}

/*****************************************************************************
 * md_estimate_size_before_relax:  How much does it look like *fragP will grow?
 *
 *      Called by base assembler just before address relaxation.
 *      Return the amount by which the fragment will grow.
 *
 *      Any symbol that is now undefined will not become defined; cobr's
 *      based on undefined symbols will have to be replaced with a compare
 *      instruction and a branch instruction, and the code fragment will grow
 *      by 4 bytes.
 *
 **************************************************************************** */
int
    md_estimate_size_before_relax(fragP, segment_type)
register fragS *fragP;
register segT segment_type;
{
        /* If symbol is undefined in this segment, go to "relaxed" state
         * (compare and branch instructions instead of cobr) right now.
         */
        if (S_GET_SEGMENT(fragP->fr_symbol) != segment_type) {
                relax_cobr(fragP);
                return 4;
        }
        return 0;
} /* md_estimate_size_before_relax() */


/*****************************************************************************
 * md_ri_to_chars:
 *      This routine exists in order to overcome machine byte-order problems
 *      when dealing with bit-field entries in the relocation_info struct.
 *
 *      But relocation info will be used on the host machine only (only
 *      executable code is actually downloaded to the i80960).  Therefore,
 *      we leave it in host byte order.
 *
 **************************************************************************** */
void md_ri_to_chars(where, ri)
char *where;
struct relocation_info *ri;
{
        *((struct relocation_info *) where) = *ri; /* structure assignment */
} /* md_ri_to_chars() */

#ifndef WORKING_DOT_WORD

int md_short_jump_size = 0;
int md_long_jump_size = 0;

void md_create_short_jump(ptr, from_addr, to_addr, frag, to_symbol)
char *ptr;
long from_addr;
long to_addr;
fragS *frag;
symbolS *to_symbol;
{
        as_fatal("failed sanity check.");
}

void
    md_create_long_jump(ptr,from_addr,to_addr,frag,to_symbol)
char *ptr;
long from_addr, to_addr;
fragS *frag;
symbolS *to_symbol;
{
        as_fatal("failed sanity check.");
}
#endif
\f
/*************************************************************
 *                                                           *
 *  FOLLOWING ARE THE LOCAL ROUTINES, IN ALPHABETICAL ORDER  *
 *                                                           *
 ************************************************************ */



/*****************************************************************************
 * brcnt_emit:  Emit code to increment inline branch counter.
 *
 *      See the comments above the declaration of 'br_cnt' for details on
 *      branch-prediction instrumentation.
 **************************************************************************** */
static void
    brcnt_emit()
{
        ctrl_fmt(BR_CNT_FUNC,CALL,1);/* Emit call to "increment" routine */
        emit(0);                /* Emit inline counter to be incremented */
}

/*****************************************************************************
 * brlab_next:  generate the next branch local label
 *
 *      See the comments above the declaration of 'br_cnt' for details on
 *      branch-prediction instrumentation.
 **************************************************************************** */
static char *
    brlab_next()
{
        static char buf[20];
        
        sprintf(buf, "%s%d", BR_LABEL_BASE, br_cnt++);
        return buf;
}

/*****************************************************************************
 * brtab_emit:  generate the fetch-prediction branch table.
 *
 *      See the comments above the declaration of 'br_cnt' for details on
 *      branch-prediction instrumentation.
 *
 *      The code emitted here would be functionally equivalent to the following
 *      example assembler source.
 *
 *                      .data
 *                      .align  2
 *         BR_TAB_NAME:
 *                      .word   0               # link to next table
 *                      .word   3               # length of table
 *                      .word   LBRANCH0        # 1st entry in table proper
 *                      .word   LBRANCH1
 *                      .word   LBRANCH2
 ***************************************************************************** */
void
    brtab_emit()
{
        int i;
        char buf[20];
        char *p;                /* Where the binary was output to */
        fixS *fixP;             /*->description of deferred address fixup */
        
        if (!instrument_branches){
                return;
        }
        
        subseg_new(SEG_DATA,0);         /*      .data */
        frag_align(2,0);                /*      .align 2 */
        record_alignment(now_seg,2);
        colon(BR_TAB_NAME);             /* BR_TAB_NAME: */
        emit(0);                        /*      .word 0 #link to next table */
        emit(br_cnt);                   /*      .word n #length of table */
        
        for (i=0; i<br_cnt; i++){
                sprintf(buf, "%s%d", BR_LABEL_BASE, i);
                p = emit(0);
                fixP = fix_new(frag_now,
                               p - frag_now->fr_literal,
                               4,
                               symbol_find(buf),
                               0,
                               0,
                               0,
                               0);
                fixP->fx_im_disp = 2; /* 32-bit displacement fix */
        }
}

/*****************************************************************************
 * cobr_fmt:    generate a COBR-format instruction
 *
 **************************************************************************** */
static
    void
    cobr_fmt(arg, opcode, oP)
char *arg[];    /* arg[0]->opcode mnemonic, arg[1-3]->operands (ascii) */
long opcode;    /* Opcode, with branch-prediction bits already set
                 *      if necessary.
                 */
struct i960_opcode *oP;
/*->description of instruction */
{
        long instr;             /* 32-bit instruction */
        struct regop regop;     /* Description of register operand */
        int n;                  /* Number of operands */
        int var_frag;           /* 1 if varying length code fragment should
                                 *      be emitted;  0 if an address fix
                                 *      should be emitted.
                                 */
        
        instr = opcode;
        n = oP->num_ops;
        
        if (n >= 1) {
                /* First operand (if any) of a COBR is always a register
                 * operand.  Parse it.
                 */
                parse_regop(&regop, arg[1], oP->operand[0]);
                instr |= (regop.n << 19) | (regop.mode << 13);
        }
        if (n >= 2) {
                /* Second operand (if any) of a COBR is always a register
                 * operand.  Parse it.
                 */
                parse_regop(&regop, arg[2], oP->operand[1]);
                instr |= (regop.n << 14) | regop.special;
        }
        
        
        if (n < 3){
                emit(instr);
                
        } else {
                if (instrument_branches){
                        brcnt_emit();
                        colon(brlab_next());
                }
                
                /* A third operand to a COBR is always a displacement.
                 * Parse it; if it's relaxable (a cobr "j" directive, or any
                 * cobr other than bbs/bbc when the "-norelax" option is not in
                 * use) set up a variable code fragment;  otherwise set up an
                 * address fix.
                 */
                var_frag = !norelax || (oP->format == COJ); /* TRUE or FALSE */
                get_cdisp(arg[3], "COBR", instr, 13, var_frag, 0);
                
                if (instrument_branches){
                        brcnt_emit();
                }
        }
} /* cobr_fmt() */


/*****************************************************************************
 * ctrl_fmt:    generate a CTRL-format instruction
 *
 **************************************************************************** */
static
    void
    ctrl_fmt(targP, opcode, num_ops)
char *targP;    /* Pointer to text of lone operand (if any) */
long opcode;    /* Template of instruction */
int num_ops;    /* Number of operands */
{
        int instrument; /* TRUE iff we should add instrumentation to track
                         * how often the branch is taken
                         */
        
        
        if (num_ops == 0){
                emit(opcode);           /* Output opcode */
        } else {
                
                instrument = instrument_branches && (opcode!=CALL)
                    && (opcode!=B) && (opcode!=RET) && (opcode!=BAL);
                
                if (instrument){
                        brcnt_emit();
                        colon(brlab_next());
                }
                
                /* The operand MUST be an ip-relative displacment. Parse it
                 * and set up address fix for the instruction we just output.
                 */
                get_cdisp(targP, "CTRL", opcode, 24, 0, 0);
                
                if (instrument){
                        brcnt_emit();
                }
        }
        
}


/*****************************************************************************
 * emit:        output instruction binary
 *
 *      Output instruction binary, in target byte order, 4 bytes at a time.
 *      Return pointer to where it was placed.
 *
 **************************************************************************** */
static
    char *
    emit(instr)
long instr;             /* Word to be output, host byte order */
{
        char *toP;      /* Where to output it */
        
        toP = frag_more(4);                     /* Allocate storage */
        md_number_to_chars(toP, instr, 4);  /* Convert to target byte order */
        return toP;
}


/*****************************************************************************
 * get_args:    break individual arguments out of comma-separated list
 *
 * Input assumptions:
 *      - all comments and labels have been removed
 *      - all strings of whitespace have been collapsed to a single blank.
 *      - all character constants ('x') have been replaced with decimal
 *
 * Output:
 *      args[0] is untouched. args[1] points to first operand, etc. All args:
 *      - are NULL-terminated
 *      - contain no whitespace
 *
 * Return value:
 *      Number of operands (0,1,2, or 3) or -1 on error.
 *
 **************************************************************************** */
static int get_args(p, args)
register char *p;       /* Pointer to comma-separated operands; MUCKED BY US */
char *args[];   /* Output arg: pointers to operands placed in args[1-3].
                 * MUST ACCOMMODATE 4 ENTRIES (args[0-3]).
                 */
{
        register int n;         /* Number of operands */
        register char *to;
        /*      char buf[4]; */
        /*      int len; */
        
        
        /* Skip lead white space */
        while (*p == ' '){
                p++;
        }
        
        if (*p == '\0'){
                return 0;
        }
        
        n = 1;
        args[1] = p;
        
        /* Squeze blanks out by moving non-blanks toward start of string.
         * Isolate operands, whenever comma is found.
         */
        to = p;
        while (*p != '\0'){
                
                if (*p == ' '){
                        p++;
                        
                } else if (*p == ','){
                        
                        /* Start of operand */
                        if (n == 3){
                                as_bad("too many operands");
                                return -1;
                        }
                        *to++ = '\0';   /* Terminate argument */
                        args[++n] = to; /* Start next argument */
                        p++;
                        
                } else {
                        *to++ = *p++;
                }
        }
        *to = '\0';
        return n;
}


/*****************************************************************************
 * get_cdisp:   handle displacement for a COBR or CTRL instruction.
 *
 *      Parse displacement for a COBR or CTRL instruction.
 *
 *      If successful, output the instruction opcode and set up for it,
 *      depending on the arg 'var_frag', either:
 *          o an address fixup to be done when all symbol values are known, or
 *          o a varying length code fragment, with address fixup info.  This
 *              will be done for cobr instructions that may have to be relaxed
 *              in to compare/branch instructions (8 bytes) if the final address
 *              displacement is greater than 13 bits.
 *
 **************************************************************************** */
static
    void
    get_cdisp(dispP, ifmtP, instr, numbits, var_frag, callj)
char *dispP;    /*->displacement as specified in source instruction */
char *ifmtP;    /*->"COBR" or "CTRL" (for use in error message) */
long instr;             /* Instruction needing the displacement */
int numbits;    /* # bits of displacement (13 for COBR, 24 for CTRL) */
int var_frag;   /* 1 if varying length code fragment should be emitted;
                 *      0 if an address fix should be emitted.
                 */
int callj;              /* 1 if callj relocation should be done; else 0 */
{
        expressionS e;  /* Parsed expression */
        fixS *fixP;     /* Structure describing needed address fix */
        char *outP;     /* Where instruction binary is output to */
        
        fixP = NULL;
        
        switch (parse_expr(dispP,&e)) {
                
        case SEG_GOOF:
                as_bad("expression syntax error");
                break;
                
        case SEG_TEXT:
        case SEG_UNKNOWN:
                if (var_frag) {
                        outP = frag_more(8);    /* Allocate worst-case storage */
                        md_number_to_chars(outP, instr, 4);
                        frag_variant(rs_machine_dependent, 4, 4, 1,
                                     adds(e), offs(e), outP, 0, 0);
                } else {
                        /* Set up a new fix structure, so address can be updated
                         * when all symbol values are known.
                         */
                        outP = emit(instr);
                        fixP = fix_new(frag_now,
                                       outP - frag_now->fr_literal,
                                       4,
                                       adds(e),
                                       0,
                                       offs(e),
                                       1,
                                       0);
                        
                        fixP->fx_callj = callj;
                        
                        /* We want to modify a bit field when the address is
                         * known.  But we don't need all the garbage in the
                         * bit_fix structure.  So we're going to lie and store
                         * the number of bits affected instead of a pointer.
                         */
                        fixP->fx_bit_fixP = (bit_fixS *) numbits;
                }
                break;
                
        case SEG_DATA:
        case SEG_BSS:
                as_bad("attempt to branch into different segment");
                break;
                
        default:
                as_bad("target of %s instruction must be a label", ifmtP);
                break;
        }
}


/*****************************************************************************
 * get_ispec:   parse a memory operand for an index specification
 *
 *      Here, an "index specification" is taken to be anything surrounded
 *      by square brackets and NOT followed by anything else.
 *
 *      If it's found, detach it from the input string, remove the surrounding
 *      square brackets, and return a pointer to it.  Otherwise, return NULL.
 *
 **************************************************************************** */
static
    char *
    get_ispec(textP)
char *textP; /*->memory operand from source instruction, no white space */
{
        char *start;    /*->start of index specification */
        char *end;      /*->end of index specification */
        
        /* Find opening square bracket, if any
         */
        start = strchr(textP, '[');
        
        if (start != NULL){
                
                /* Eliminate '[', detach from rest of operand */
                *start++ = '\0';
                
                end = strchr(start, ']');
                
                if (end == NULL){
                        as_bad("unmatched '['");
                        
                } else {
                        /* Eliminate ']' and make sure it was the last thing
                         * in the string.
                         */
                        *end = '\0';
                        if (*(end+1) != '\0'){
                                as_bad("garbage after index spec ignored");
                        }
                }
        }
        return start;
}

/*****************************************************************************
 * get_regnum:
 *
 *      Look up a (suspected) register name in the register table and return the
 *      associated register number (or -1 if not found).
 *
 **************************************************************************** */
static
    int
    get_regnum(regname)
char *regname;  /* Suspected register name */
{
        int *rP;
        
        rP = (int *) hash_find(reg_hash, regname);
        return (rP == NULL) ? -1 : *rP;
}


/*****************************************************************************
 * i_scan:      perform lexical scan of ascii assembler instruction.
 *
 * Input assumptions:
 *      - input string is an i80960 instruction (not a pseudo-op)
 *      - all comments and labels have been removed
 *      - all strings of whitespace have been collapsed to a single blank.
 *
 * Output:
 *      args[0] points to opcode, other entries point to operands. All strings:
 *      - are NULL-terminated
 *      - contain no whitespace
 *      - have character constants ('x') replaced with a decimal number
 *
 * Return value:
 *      Number of operands (0,1,2, or 3) or -1 on error.
 *
 **************************************************************************** */
static int i_scan(iP, args)
register char *iP;      /* Pointer to ascii instruction;  MUCKED BY US. */
char *args[];   /* Output arg: pointers to opcode and operands placed
                 *      here.  MUST ACCOMMODATE 4 ENTRIES.
                 */
{
        
        /* Isolate opcode */
        if (*(iP) == ' ') {
                iP++;
        } /* Skip lead space, if any */
        args[0] = iP;
        for (; *iP != ' '; iP++) {
                if (*iP == '\0') {
                        /* There are no operands */
                        if (args[0] == iP) {
                                /* We never moved: there was no opcode either! */
                                as_bad("missing opcode");
                                return -1;
                        }
                        return 0;
                }
        }
        *iP++ = '\0';   /* Terminate opcode */
        return(get_args(iP, args));
} /* i_scan() */


/*****************************************************************************
 * mem_fmt:     generate a MEMA- or MEMB-format instruction
 *
 **************************************************************************** */
static void mem_fmt(args, oP, callx)
char *args[];   /* args[0]->opcode mnemonic, args[1-3]->operands */
struct i960_opcode *oP; /* Pointer to description of instruction */
int callx; /* Is this a callx opcode */
{
        int i;                  /* Loop counter */
        struct regop regop;     /* Description of register operand */
        char opdesc;            /* Operand descriptor byte */
        memS instr;             /* Description of binary to be output */
        char *outP;             /* Where the binary was output to */
        expressionS expr;       /* Parsed expression */
        fixS *fixP;             /*->description of deferred address fixup */
        
        memset(&instr, '\0', sizeof(memS));
        instr.opcode = oP->opcode;
        
        /* Process operands. */
        for (i = 1; i <= oP->num_ops; i++){
                opdesc = oP->operand[i-1];
                
                if (MEMOP(opdesc)){
                        parse_memop(&instr, args[i], oP->format);
                } else {
                        parse_regop(&regop, args[i], opdesc);
                        instr.opcode |= regop.n << 19;
                }
        }
        
        /* Output opcode */
        outP = emit(instr.opcode);
        
        if (instr.disp == 0){
                return;
        }
        
        /* Parse and process the displacement */
        switch (parse_expr(instr.e,&expr)){
                
        case SEG_GOOF:
                as_bad("expression syntax error");
                break;
                
        case SEG_ABSOLUTE:
                if (instr.disp == 32){
                        (void) emit(offs(expr));        /* Output displacement */
                } else {
                        /* 12-bit displacement */
                        if (offs(expr) & ~0xfff){
                                /* Won't fit in 12 bits: convert already-output
                                 * instruction to MEMB format, output
                                 * displacement.
                                 */
                                mema_to_memb(outP);
                                (void) emit(offs(expr));
                        } else {
                                /* WILL fit in 12 bits:  OR into opcode and
                                 * overwrite the binary we already put out
                                 */
                                instr.opcode |= offs(expr);
                                md_number_to_chars(outP, instr.opcode, 4);
                        }
                }
                break;
                
        case SEG_DIFFERENCE:
        case SEG_TEXT:
        case SEG_DATA:
        case SEG_BSS:
        case SEG_UNKNOWN:
                if (instr.disp == 12){
                        /* Displacement is dependent on a symbol, whose value
                         * may change at link time.  We HAVE to reserve 32 bits.
                         * Convert already-output opcode to MEMB format.
                         */
                        mema_to_memb(outP);
                }
                
                /* Output 0 displacement and set up address fixup for when
                 * this symbol's value becomes known.
                 */
                outP = emit((long) 0);
                fixP = fix_new(frag_now,
                               outP - frag_now->fr_literal,
                               4,
                               adds(expr),
                               subs(expr),
                               offs(expr),
                               0,
                               NO_RELOC);
                fixP->fx_im_disp = 2; /* 32-bit displacement fix */
                fixP->fx_bsr = callx; /*SAC LD RELAX HACK */ /* Mark reloc as being in i stream */
                break;
                
        default:
                BAD_CASE(segs(expr));
                break;
        }
} /* memfmt() */


/*****************************************************************************
 * mema_to_memb:        convert a MEMA-format opcode to a MEMB-format opcode.
 *
 * There are 2 possible MEMA formats:
 *      - displacement only
 *      - displacement + abase
 *
 * They are distinguished by the setting of the MEMA_ABASE bit.
 *
 **************************************************************************** */
static void mema_to_memb(opcodeP)
char *opcodeP;  /* Where to find the opcode, in target byte order */
{
        long opcode;    /* Opcode in host byte order */
        long mode;      /* Mode bits for MEMB instruction */
        
        opcode = md_chars_to_number(opcodeP, 4);
        know(!(opcode & MEMB_BIT));
        
        mode = MEMB_BIT | D_BIT;
        if (opcode & MEMA_ABASE){
                mode |= A_BIT;
        }
        
        opcode &= 0xffffc000;   /* Clear MEMA offset and mode bits */
        opcode |= mode;         /* Set MEMB mode bits */
        
        md_number_to_chars(opcodeP, opcode, 4);
} /* mema_to_memb() */


/*****************************************************************************
 * parse_expr:          parse an expression
 *
 *      Use base assembler's expression parser to parse an expression.
 *      It, unfortunately, runs off a global which we have to save/restore
 *      in order to make it work for us.
 *
 *      An empty expression string is treated as an absolute 0.
 *
 *      Return "segment" to which the expression evaluates.
 *      Return SEG_GOOF regardless of expression evaluation if entire input
 *      string is not consumed in the evaluation -- tolerate no dangling junk!
 *
 **************************************************************************** */
static
    segT
    parse_expr(textP, expP)
char *textP;    /* Text of expression to be parsed */
expressionS *expP;      /* Where to put the results of parsing */
{
        char *save_in;  /* Save global here */
        segT seg;       /* Segment to which expression evaluates */
        symbolS *symP;
        
        know(textP);
        
        if (*textP == '\0') {
                /* Treat empty string as absolute 0 */
                expP->X_add_symbol = expP->X_subtract_symbol = NULL;
                expP->X_add_number = 0;
                seg = expP->X_seg = SEG_ABSOLUTE;
                
        } else {
                save_in = input_line_pointer;   /* Save global */
                input_line_pointer = textP;     /* Make parser work for us */
                
                seg = expression(expP);
                if (input_line_pointer - textP != strlen(textP)) {
                        /* Did not consume all of the input */
                        seg = SEG_GOOF;
                }
                symP = expP->X_add_symbol;
                if (symP && (hash_find(reg_hash, S_GET_NAME(symP)))) {
                        /* Register name in an expression */
                        seg = SEG_GOOF;
                }
                
                input_line_pointer = save_in;   /* Restore global */
        }
        return seg;
}


/*****************************************************************************
 * parse_ldcont:
 *      Parse and replace a 'ldconst' pseudo-instruction with an appropriate
 *      i80960 instruction.
 *
 *      Assumes the input consists of:
 *              arg[0]  opcode mnemonic ('ldconst')
 *              arg[1]  first operand (constant)
 *              arg[2]  name of register to be loaded
 *
 *      Replaces opcode and/or operands as appropriate.
 *
 *      Returns the new number of arguments, or -1 on failure.
 *
 **************************************************************************** */
static
    int
    parse_ldconst(arg)
char *arg[];    /* See above */
{
        int n;                  /* Constant to be loaded */
        int shift;              /* Shift count for "shlo" instruction */
        static char buf[5];     /* Literal for first operand */
        static char buf2[5];    /* Literal for second operand */
        expressionS e;          /* Parsed expression */
        
        
        arg[3] = NULL;  /* So we can tell at the end if it got used or not */
        
        switch(parse_expr(arg[1],&e)){
                
        case SEG_TEXT:
        case SEG_DATA:
        case SEG_BSS:
        case SEG_UNKNOWN:
        case SEG_DIFFERENCE:
                /* We're dependent on one or more symbols -- use "lda" */
                arg[0] = "lda";
                break;
                
        case SEG_ABSOLUTE:
                /* Try the following mappings:
                 *      ldconst 0,<reg>  ->mov  0,<reg>
                 *      ldconst 31,<reg> ->mov  31,<reg>
                 *      ldconst 32,<reg> ->addo 1,31,<reg>
                 *      ldconst 62,<reg> ->addo 31,31,<reg>
                 *      ldconst 64,<reg> ->shlo 8,3,<reg>
                 *      ldconst -1,<reg> ->subo 1,0,<reg>
                 *      ldconst -31,<reg>->subo 31,0,<reg>
                 *
                 * anthing else becomes:
                 *      lda xxx,<reg>
                 */
                n = offs(e);
                if ((0 <= n) && (n <= 31)){
                        arg[0] = "mov";
                        
                } else if ((-31 <= n) && (n <= -1)){
                        arg[0] = "subo";
                        arg[3] = arg[2];
                        sprintf(buf, "%d", -n);
                        arg[1] = buf;
                        arg[2] = "0";
                        
                } else if ((32 <= n) && (n <= 62)){
                        arg[0] = "addo";
                        arg[3] = arg[2];
                        arg[1] = "31";
                        sprintf(buf, "%d", n-31);
                        arg[2] = buf;
                        
                } else if ((shift = shift_ok(n)) != 0){
                        arg[0] = "shlo";
                        arg[3] = arg[2];
                        sprintf(buf, "%d", shift);
                        arg[1] = buf;
                        sprintf(buf2, "%d", n >> shift);
                        arg[2] = buf2;
                        
                } else {
                        arg[0] = "lda";
                }
                break;
                
        default:
                as_bad("invalid constant");
                return -1;
                break;
        }
        return (arg[3] == 0) ? 2: 3;
}

/*****************************************************************************
 * parse_memop: parse a memory operand
 *
 *      This routine is based on the observation that the 4 mode bits of the
 *      MEMB format, taken individually, have fairly consistent meaning:
 *
 *               M3 (bit 13): 1 if displacement is present (D_BIT)
 *               M2 (bit 12): 1 for MEMB instructions (MEMB_BIT)
 *               M1 (bit 11): 1 if index is present (I_BIT)
 *               M0 (bit 10): 1 if abase is present (A_BIT)
 *
 *      So we parse the memory operand and set bits in the mode as we find
 *      things.  Then at the end, if we go to MEMB format, we need only set
 *      the MEMB bit (M2) and our mode is built for us.
 *
 *      Unfortunately, I said "fairly consistent".  The exceptions:
 *
 *               DBIA
 *               0100   Would seem illegal, but means "abase-only".
 *
 *               0101   Would seem to mean "abase-only" -- it means IP-relative.
 *                      Must be converted to 0100.
 *
 *               0110   Would seem to mean "index-only", but is reserved.
 *                      We turn on the D bit and provide a 0 displacement.
 *
 *      The other thing to observe is that we parse from the right, peeling
 *      things * off as we go:  first any index spec, then any abase, then
 *      the displacement.
 *
 **************************************************************************** */
static
    void
    parse_memop(memP, argP, optype)
memS *memP;     /* Where to put the results */
char *argP;     /* Text of the operand to be parsed */
int optype;     /* MEM1, MEM2, MEM4, MEM8, MEM12, or MEM16 */
{
        char *indexP;   /* Pointer to index specification with "[]" removed */
        char *p;        /* Temp char pointer */
        char iprel_flag;/* True if this is an IP-relative operand */
        int regnum;     /* Register number */
        int scale;      /* Scale factor: 1,2,4,8, or 16.  Later converted
                         *      to internal format (0,1,2,3,4 respectively).
                         */
        int mode;       /* MEMB mode bits */
        int *intP;      /* Pointer to register number */
        
        /* The following table contains the default scale factors for each
         * type of memory instruction.  It is accessed using (optype-MEM1)
         * as an index -- thus it assumes the 'optype' constants are assigned
         * consecutive values, in the order they appear in this table
         */
        static int def_scale[] = {
                1,      /* MEM1 */
                2,      /* MEM2 */
                4,      /* MEM4 */
                8,      /* MEM8 */
                -1,     /* MEM12 -- no valid default */
                16      /* MEM16 */
            };
        
        
        iprel_flag = mode = 0;
        
        /* Any index present? */
        indexP = get_ispec(argP);
        if (indexP) {
                p = strchr(indexP, '*');
                if (p == NULL) {
                        /* No explicit scale -- use default for this
                         *instruction type.
                         */
                        scale = def_scale[ optype - MEM1 ];
                } else {
                        *p++ = '\0';    /* Eliminate '*' */
                        
                        /* Now indexP->a '\0'-terminated register name,
                         * and p->a scale factor.
                         */
                        
                        if (!strcmp(p,"16")){
                                scale = 16;
                        } else if (strchr("1248",*p) && (p[1] == '\0')){
                                scale = *p - '0';
                        } else {
                                scale = -1;
                        }
                }
                
                regnum = get_regnum(indexP);            /* Get index reg. # */
                if (!IS_RG_REG(regnum)){
                        as_bad("invalid index register");
                        return;
                }
                
                /* Convert scale to its binary encoding */
                switch (scale){
                case  1: scale = 0 << 7; break;
                case  2: scale = 1 << 7; break;
                case  4: scale = 2 << 7; break;
                case  8: scale = 3 << 7; break;
                case 16: scale = 4 << 7; break;
                default: as_bad("invalid scale factor"); return;
                };
                
                memP->opcode |= scale | regnum;  /* Set index bits in opcode */
                mode |= I_BIT;                  /* Found a valid index spec */
        }
        
        /* Any abase (Register Indirect) specification present? */
        if ((p = strrchr(argP,'(')) != NULL) {
                /* "(" is there -- does it start a legal abase spec?
                 * (If not it could be part of a displacement expression.)
                 */
                intP = (int *) hash_find(areg_hash, p);
                if (intP != NULL){
                        /* Got an abase here */
                        regnum = *intP;
                        *p = '\0';      /* discard register spec */
                        if (regnum == IPREL){
                                /* We have to specialcase ip-rel mode */
                                iprel_flag = 1;
                        } else {
                                memP->opcode |= regnum << 14;
                                mode |= A_BIT;
                        }
                }
        }
        
        /* Any expression present? */
        memP->e = argP;
        if (*argP != '\0'){
                mode |= D_BIT;
        }
        
        /* Special-case ip-relative addressing */
        if (iprel_flag){
                if (mode & I_BIT){
                        syntax();
                } else {
                        memP->opcode |= 5 << 10;        /* IP-relative mode */
                        memP->disp = 32;
                }
                return;
        }
        
        /* Handle all other modes */
        switch (mode){
        case D_BIT | A_BIT:
                /* Go with MEMA instruction format for now (grow to MEMB later
                 *      if 12 bits is not enough for the displacement).
                 * MEMA format has a single mode bit: set it to indicate
                 *      that abase is present.
                 */
                memP->opcode |= MEMA_ABASE;
                memP->disp = 12;
                break;
                
        case D_BIT:
                /* Go with MEMA instruction format for now (grow to MEMB later
                 *      if 12 bits is not enough for the displacement).
                 */
                memP->disp = 12;
                break;
                
        case A_BIT:
                /* For some reason, the bit string for this mode is not
                 * consistent:  it should be 0 (exclusive of the MEMB bit),
                 * so we set it "by hand" here.
                 */
                memP->opcode |= MEMB_BIT;
                break;
                
        case A_BIT | I_BIT:
                /* set MEMB bit in mode, and OR in mode bits */
                memP->opcode |= mode | MEMB_BIT;
                break;
                
        case I_BIT:
                /* Treat missing displacement as displacement of 0 */
                mode |= D_BIT;
                /***********************
                 * Fall into next case *
                 ********************** */
        case D_BIT | A_BIT | I_BIT:
        case D_BIT | I_BIT:
                /* set MEMB bit in mode, and OR in mode bits */
                memP->opcode |= mode | MEMB_BIT;
                memP->disp = 32;
                break;
                
        default:
                syntax();
                break;
        }
}

/*****************************************************************************
 * parse_po:    parse machine-dependent pseudo-op
 *
 *      This is a top-level routine for machine-dependent pseudo-ops.  It slurps
 *      up the rest of the input line, breaks out the individual arguments,
 *      and dispatches them to the correct handler.
 **************************************************************************** */
static
    void
    parse_po(po_num)
int po_num;      /* Pseudo-op number:  currently S_LEAFPROC or S_SYSPROC */
{
        char *args[4];  /* Pointers operands, with no embedded whitespace.
                         *      arg[0] unused.
                         *      arg[1-3]->operands
                         */
        int n_ops;      /* Number of operands */
        char *p;        /* Pointer to beginning of unparsed argument string */
        char eol;       /* Character that indicated end of line */
        
        extern char is_end_of_line[];
        
        /* Advance input pointer to end of line. */
        p = input_line_pointer;
        while (!is_end_of_line[ *input_line_pointer ]){
                input_line_pointer++;
        }
        eol = *input_line_pointer;      /* Save end-of-line char */
        *input_line_pointer = '\0';     /* Terminate argument list */
        
        /* Parse out operands */
        n_ops = get_args(p, args);
        if (n_ops == -1){
                return;
        }
        
        /* Dispatch to correct handler */
        switch(po_num){
        case S_SYSPROC:         s_sysproc(n_ops, args); break;
        case S_LEAFPROC:        s_leafproc(n_ops, args);        break;
        default:                BAD_CASE(po_num);               break;
        }
        
        /* Restore eol, so line numbers get updated correctly.  Base assembler
         * assumes we leave input pointer pointing at char following the eol.
         */
        *input_line_pointer++ = eol;
}

/*****************************************************************************
 * parse_regop: parse a register operand.
 *
 *      In case of illegal operand, issue a message and return some valid
 *      information so instruction processing can continue.
 **************************************************************************** */
static
    void
    parse_regop(regopP, optext, opdesc)
struct regop *regopP; /* Where to put description of register operand */
char *optext;   /* Text of operand */
char opdesc;    /* Descriptor byte:  what's legal for this operand */
{
        int n;          /* Register number */
        expressionS e;  /* Parsed expression */
        
        /* See if operand is a register */
        n = get_regnum(optext);
        if (n >= 0){
                if (IS_RG_REG(n)){
                        /* global or local register */
                        if (!REG_ALIGN(opdesc,n)){
                                as_bad("unaligned register");
                        }
                        regopP->n = n;
                        regopP->mode = 0;
                        regopP->special = 0;
                        return;
                } else if (IS_FP_REG(n) && FP_OK(opdesc)){
                        /* Floating point register, and it's allowed */
                        regopP->n = n - FP0;
                        regopP->mode = 1;
                        regopP->special = 0;
                        return;
                } else if (IS_SF_REG(n) && SFR_OK(opdesc)){
                        /* Special-function register, and it's allowed */
                        regopP->n = n - SF0;
                        regopP->mode = 0;
                        regopP->special = 1;
                        if (!targ_has_sfr(regopP->n)){
                                as_bad("no such sfr in this architecture");
                        }
                        return;
                }
        } else if (LIT_OK(opdesc)){
                /*
                 * How about a literal?
                 */
                regopP->mode = 1;
                regopP->special = 0;
                if (FP_OK(opdesc)){     /* floating point literal acceptable */
                        /* Skip over 0f, 0d, or 0e prefix */
                        if ( (optext[0] == '0')
                            && (optext[1] >= 'd')
                            && (optext[1] <= 'f') ){
                                optext += 2;
                        }
                        
                        if (!strcmp(optext,"0.0") || !strcmp(optext,"0") ){
                                regopP->n = 0x10;
                                return;
                        }
                        if (!strcmp(optext,"1.0") || !strcmp(optext,"1") ){
                                regopP->n = 0x16;
                                return;
                        }
                        
                } else {                /* fixed point literal acceptable */
                        if ((parse_expr(optext,&e) != SEG_ABSOLUTE)
                            ||   (offs(e) < 0) || (offs(e) > 31)){
                                as_bad("illegal literal");
                                offs(e) = 0;
                        }
                        regopP->n = offs(e);
                        return;
                }
        }
        
        /* Nothing worked */
        syntax();
        regopP->mode = 0;       /* Register r0 is always a good one */
        regopP->n = 0;
        regopP->special = 0;
} /* parse_regop() */

/*****************************************************************************
 * reg_fmt:     generate a REG-format instruction
 *
 **************************************************************************** */
static void reg_fmt(args, oP)
char *args[];   /* args[0]->opcode mnemonic, args[1-3]->operands */
struct i960_opcode *oP; /* Pointer to description of instruction */
{
        long instr;             /* Binary to be output */
        struct regop regop;     /* Description of register operand */
        int n_ops;              /* Number of operands */
        
        
        instr = oP->opcode;
        n_ops = oP->num_ops;
        
        if (n_ops >= 1){
                parse_regop(&regop, args[1], oP->operand[0]);
                
                if ((n_ops == 1) && !(instr & M3)){
                        /* 1-operand instruction in which the dst field should
                         * be used (instead of src1).
                         */
                        regop.n       <<= 19;
                        if (regop.special){
                                regop.mode = regop.special;
                        }
                        regop.mode    <<= 13;
                        regop.special = 0;
                } else {
                        /* regop.n goes in bit 0, needs no shifting */
                        regop.mode    <<= 11;
                        regop.special <<= 5;
                }
                instr |= regop.n | regop.mode | regop.special;
        }
        
        if (n_ops >= 2) {
                parse_regop(&regop, args[2], oP->operand[1]);
                
                if ((n_ops == 2) && !(instr & M3)){
                        /* 2-operand instruction in which the dst field should
                         * be used instead of src2).
                         */
                        regop.n       <<= 19;
                        if (regop.special){
                                regop.mode = regop.special;
                        }
                        regop.mode    <<= 13;
                        regop.special = 0;
                } else {
                        regop.n       <<= 14;
                        regop.mode    <<= 12;
                        regop.special <<= 6;
                }
                instr |= regop.n | regop.mode | regop.special;
        }
        if (n_ops == 3){
                parse_regop(&regop, args[3], oP->operand[2]);
                if (regop.special){
                        regop.mode = regop.special;
                }
                instr |= (regop.n <<= 19) | (regop.mode <<= 13);
        }
        emit(instr);
}


/*****************************************************************************
 * relax_cobr:
 *      Replace cobr instruction in a code fragment with equivalent branch and
 *      compare instructions, so it can reach beyond a 13-bit displacement.
 *      Set up an address fix/relocation for the new branch instruction.
 *
 **************************************************************************** */

/* This "conditional jump" table maps cobr instructions into equivalent
 * compare and branch opcodes.
 */
static
    struct {
            long compare;
            long branch;
    } coj[] = {         /* COBR OPCODE: */
            CHKBIT,     BNO,    /*      0x30 - bbc */
            CMPO,       BG,     /*      0x31 - cmpobg */
            CMPO,       BE,     /*      0x32 - cmpobe */
            CMPO,       BGE,    /*      0x33 - cmpobge */
            CMPO,       BL,     /*      0x34 - cmpobl */
            CMPO,       BNE,    /*      0x35 - cmpobne */
            CMPO,       BLE,    /*      0x36 - cmpoble */
            CHKBIT,     BO,     /*      0x37 - bbs */
            CMPI,       BNO,    /*      0x38 - cmpibno */
            CMPI,       BG,     /*      0x39 - cmpibg */
            CMPI,       BE,     /*      0x3a - cmpibe */
            CMPI,       BGE,    /*      0x3b - cmpibge */
            CMPI,       BL,     /*      0x3c - cmpibl */
            CMPI,       BNE,    /*      0x3d - cmpibne */
            CMPI,       BLE,    /*      0x3e - cmpible */
            CMPI,       BO,     /*      0x3f - cmpibo */
    };

static
    void
    relax_cobr(fragP)
register fragS *fragP;  /* fragP->fr_opcode is assumed to point to
                         * the cobr instruction, which comes at the
                         * end of the code fragment.
                         */
{
        int opcode, src1, src2, m1, s2;
        /* Bit fields from cobr instruction */
        long bp_bits;   /* Branch prediction bits from cobr instruction */
        long instr;     /* A single i960 instruction */
        char *iP;       /*->instruction to be replaced */
        fixS *fixP;     /* Relocation that can be done at assembly time */
        
        /* PICK UP & PARSE COBR INSTRUCTION */
        iP = fragP->fr_opcode;
        instr  = md_chars_to_number(iP, 4);
        opcode = ((instr >> 24) & 0xff) - 0x30; /* "-0x30" for table index */
        src1   = (instr >> 19) & 0x1f;
        m1     = (instr >> 13) & 1;
        s2     = instr & 1;
        src2   = (instr >> 14) & 0x1f;
        bp_bits= instr & BP_MASK;
        
        /* GENERATE AND OUTPUT COMPARE INSTRUCTION */
        instr = coj[opcode].compare
            | src1 | (m1 << 11) | (s2 << 6) | (src2 << 14);
        md_number_to_chars(iP, instr, 4);
        
        /* OUTPUT BRANCH INSTRUCTION */
        md_number_to_chars(iP+4, coj[opcode].branch | bp_bits, 4);
        
        /* SET UP ADDRESS FIXUP/RELOCATION */
        fixP = fix_new(fragP,
                       iP+4 - fragP->fr_literal,
                       4,
                       fragP->fr_symbol,
                       0,
                       fragP->fr_offset,
                       1,
                       0);
        
        fixP->fx_bit_fixP = (bit_fixS *) 24;    /* Store size of bit field */
        
        fragP->fr_fix += 4;
        frag_wane(fragP);
}


/*****************************************************************************
 * reloc_callj: Relocate a 'callj' instruction
 *
 *      This is a "non-(GNU)-standard" machine-dependent hook.  The base
 *      assembler calls it when it decides it can relocate an address at
 *      assembly time instead of emitting a relocation directive.
 *
 *      Check to see if the relocation involves a 'callj' instruction to a:
 *          sysproc:    Replace the default 'call' instruction with a 'calls'
 *          leafproc:   Replace the default 'call' instruction with a 'bal'.
 *          other proc: Do nothing.
 *
 *      See b.out.h for details on the 'n_other' field in a symbol structure.
 *
 * IMPORTANT!:
 *      Assumes the caller has already figured out, in the case of a leafproc,
 *      to use the 'bal' entry point, and has substituted that symbol into the
 *      passed fixup structure.
 *
 **************************************************************************** */
void reloc_callj(fixP)
fixS *fixP;             /* Relocation that can be done at assembly time */
{
        char *where;    /*->the binary for the instruction being relocated */
        
        if (!fixP->fx_callj) {
                return;
        } /* This wasn't a callj instruction in the first place */

        where = fixP->fx_frag->fr_literal + fixP->fx_where;
        
        if (TC_S_IS_SYSPROC(fixP->fx_addsy)) {
                /* Symbol is a .sysproc: replace 'call' with 'calls'.
                 * System procedure number is (other-1).
                 */
                md_number_to_chars(where, CALLS|TC_S_GET_SYSPROC(fixP->fx_addsy), 4);
                
                /* Nothing else needs to be done for this instruction.
                 * Make sure 'md_number_to_field()' will perform a no-op.
                 */
                fixP->fx_bit_fixP = (bit_fixS *) 1;
                
        } else if (TC_S_IS_CALLNAME(fixP->fx_addsy)) {
                /* Should not happen: see block comment above */
                as_fatal("Trying to 'bal' to %s", S_GET_NAME(fixP->fx_addsy));
                
        } else if (TC_S_IS_BALNAME(fixP->fx_addsy)) {
                /* Replace 'call' with 'bal';  both instructions have
                 * the same format, so calling code should complete
                 * relocation as if nothing happened here.
                 */
                md_number_to_chars(where, BAL, 4);
        } else if (TC_S_IS_BADPROC(fixP->fx_addsy)) {
                as_bad("Looks like a proc, but can't tell what kind.\n");
        } /* switch on proc type */
        
        /* else Symbol is neither a sysproc nor a leafproc */
        
        return;
} /* reloc_callj() */


/*****************************************************************************
 * s_leafproc:  process .leafproc pseudo-op
 *
 *      .leafproc takes two arguments, the second one is optional:
 *              arg[1]: name of 'call' entry point to leaf procedure
 *              arg[2]: name of 'bal' entry point to leaf procedure
 *
 *      If the two arguments are identical, or if the second one is missing,
 *      the first argument is taken to be the 'bal' entry point.
 *
 *      If there are 2 distinct arguments, we must make sure that the 'bal'
 *      entry point immediately follows the 'call' entry point in the linked
 *      list of symbols.
 *
 **************************************************************************** */
static void s_leafproc(n_ops, args)
int n_ops;              /* Number of operands */
char *args[];   /* args[1]->1st operand, args[2]->2nd operand */
{
        symbolS *callP; /* Pointer to leafproc 'call' entry point symbol */
        symbolS *balP;  /* Pointer to leafproc 'bal' entry point symbol */
        
        if ((n_ops != 1) && (n_ops != 2)) {
                as_bad("should have 1 or 2 operands");
                return;
        } /* Check number of arguments */
        
        /* Find or create symbol for 'call' entry point. */
        callP = symbol_find_or_make(args[1]);
        
        if (TC_S_IS_CALLNAME(callP)) {
                as_warn("Redefining leafproc %s", S_GET_NAME(callP));
        } /* is leafproc */
        
        /* If that was the only argument, use it as the 'bal' entry point.
         * Otherwise, mark it as the 'call' entry point and find or create
         * another symbol for the 'bal' entry point.
         */
        if ((n_ops == 1) || !strcmp(args[1],args[2])) {
                TC_S_FORCE_TO_BALNAME(callP);
                
        } else {
                TC_S_FORCE_TO_CALLNAME(callP);
                
                balP = symbol_find_or_make(args[2]);
                if (TC_S_IS_CALLNAME(balP)) {
                        as_warn("Redefining leafproc %s", S_GET_NAME(balP));
                }
                TC_S_FORCE_TO_BALNAME(balP);
                
                tc_set_bal_of_call(callP, balP);
        } /* if only one arg, or the args are the same */
        
        return;
} /* s_leafproc() */


/*
 * s_sysproc:   process .sysproc pseudo-op
 *
 *      .sysproc takes two arguments:
 *              arg[1]: name of entry point to system procedure
 *              arg[2]: 'entry_num' (index) of system procedure in the range
 *                      [0,31] inclusive.
 *
 *      For [ab].out, we store the 'entrynum' in the 'n_other' field of
 *      the symbol.  Since that entry is normally 0, we bias 'entrynum'
 *      by adding 1 to it.  It must be unbiased before it is used.
 */
static void s_sysproc(n_ops, args)
int n_ops; /* Number of operands */
char *args[]; /* args[1]->1st operand, args[2]->2nd operand */
{
        expressionS exp;
        symbolS *symP;
        
        if (n_ops != 2) {
                as_bad("should have two operands");
                return;
        } /* bad arg count */
        
        /* Parse "entry_num" argument and check it for validity. */
        if ((parse_expr(args[2],&exp) != SEG_ABSOLUTE)
            || (offs(exp) < 0)
            || (offs(exp) > 31)) {
                as_bad("'entry_num' must be absolute number in [0,31]");
                return;
        }
        
        /* Find/make symbol and stick entry number (biased by +1) into it */
        symP = symbol_find_or_make(args[1]);
        
        if (TC_S_IS_SYSPROC(symP)) {
                as_warn("Redefining entrynum for sysproc %s", S_GET_NAME(symP));
        } /* redefining */
        
        TC_S_SET_SYSPROC(symP, offs(exp)); /* encode entry number */
        TC_S_FORCE_TO_SYSPROC(symP);
        
        return;
} /* s_sysproc() */


/*****************************************************************************
 * shift_ok:
 *      Determine if a "shlo" instruction can be used to implement a "ldconst".
 *      This means that some number X < 32 can be shifted left to produce the
 *      constant of interest.
 *
 *      Return the shift count, or 0 if we can't do it.
 *      Caller calculates X by shifting original constant right 'shift' places.
 *
 **************************************************************************** */
static
    int
    shift_ok(n)
int n;          /* The constant of interest */
{
        int shift;      /* The shift count */
        
        if (n <= 0){
                /* Can't do it for negative numbers */
                return 0;
        }
        
        /* Shift 'n' right until a 1 is about to be lost */
        for (shift = 0; (n & 1) == 0; shift++){
                n >>= 1;
        }
        
        if (n >= 32){
                return 0;
        }
        return shift;
}


/*****************************************************************************
 * syntax:      issue syntax error
 *
 **************************************************************************** */
static void syntax() {
        as_bad("syntax error");
} /* syntax() */


/*****************************************************************************
 * targ_has_sfr:
 *      Return TRUE iff the target architecture supports the specified
 *      special-function register (sfr).
 *
 **************************************************************************** */
static
    int
    targ_has_sfr(n)
int n;  /* Number (0-31) of sfr */
{
        switch (architecture){
        case ARCH_KA:
        case ARCH_KB:
        case ARCH_MC:
                return 0;
        case ARCH_CA:
        default:
                return ((0<=n) && (n<=2));
        }
}


/*****************************************************************************
 * targ_has_iclass:
 *      Return TRUE iff the target architecture supports the indicated
 *      class of instructions.
 *
 **************************************************************************** */
static
    int
    targ_has_iclass(ic)
int ic; /* Instruction class;  one of:
         *      I_BASE, I_CX, I_DEC, I_KX, I_FP, I_MIL, I_CASIM
         */
{
        iclasses_seen |= ic;
        switch (architecture){
        case ARCH_KA:   return ic & (I_BASE | I_KX);
        case ARCH_KB:   return ic & (I_BASE | I_KX | I_FP | I_DEC);
        case ARCH_MC:   return ic & (I_BASE | I_KX | I_FP | I_DEC | I_MIL);
        case ARCH_CA:   return ic & (I_BASE | I_CX | I_CASIM);
        default:
                if ((iclasses_seen & (I_KX|I_FP|I_DEC|I_MIL))
                    &&   (iclasses_seen & I_CX)){
                        as_warn("architecture of opcode conflicts with that of earlier instruction(s)");
                        iclasses_seen &= ~ic;
                }
                return 1;
        }
}


/* Parse an operand that is machine-specific.
   We just return without modifying the expression if we have nothing
   to do. */

/* ARGSUSED */
void
    md_operand (expressionP)
expressionS *expressionP;
{
}

/* We have no need to default values of symbols. */

/* ARGSUSED */
symbolS *md_undefined_symbol(name)
char *name;
{
        return 0;
} /* md_undefined_symbol() */

/* Exactly what point is a PC-relative offset relative TO?
   On the i960, they're relative to the address of the instruction,
   which we have set up as the address of the fixup too. */
long
    md_pcrel_from (fixP)
fixS *fixP;
{
        return fixP->fx_where + fixP->fx_frag->fr_address;
}

void
    md_apply_fix(fixP, val)
fixS *fixP;
long val;
{
        char *place = fixP->fx_where + fixP->fx_frag->fr_literal;
        
        if (!fixP->fx_bit_fixP) {
                
                switch (fixP->fx_im_disp) {
                case 0:
                        fixP->fx_addnumber = val;
                        md_number_to_imm(place, val, fixP->fx_size, fixP);
                        break;
                case 1:
                        md_number_to_disp(place,
                                          fixP->fx_pcrel ? val + fixP->fx_pcrel_adjust : val,
                                          fixP->fx_size);
                        break;
                case 2: /* fix requested for .long .word etc */
                        md_number_to_chars(place, val, fixP->fx_size);
                        break;
                default:
                        as_fatal("Internal error in md_apply_fix() in file \"%s\"", __FILE__);
                } /* OVE: maybe one ought to put _imm _disp _chars in one md-func */
        } else {
                md_number_to_field(place, val, fixP->fx_bit_fixP);
        }
        
        return;
} /* md_apply_fix() */

#if defined(OBJ_AOUT) | defined(OBJ_BOUT)
void tc_bout_fix_to_chars(where, fixP, segment_address_in_file)
char *where;
fixS *fixP;
relax_addressT segment_address_in_file;
{
        static unsigned char nbytes_r_length [] = { 42, 0, 1, 42, 2 };
        struct relocation_info ri;
        symbolS *symbolP;
        
        /* JF this is for paranoia */
        memset((char *)&ri, '\0', sizeof(ri));
        symbolP = fixP->fx_addsy;
        know(symbolP != 0 || fixP->fx_r_type != NO_RELOC);
        ri.r_bsr = fixP->fx_bsr; /*SAC LD RELAX HACK */ 
        /* These two 'cuz of NS32K */
        ri.r_callj = fixP->fx_callj;
        if(fixP->fx_bit_fixP) {
          ri.r_length = 1;
        }
        else {
          ri.r_length = nbytes_r_length[fixP->fx_size];
        }
        ri.r_pcrel = fixP->fx_pcrel;
        ri.r_address = fixP->fx_frag->fr_address + fixP->fx_where - segment_address_in_file;
        
        if (fixP->fx_r_type != NO_RELOC)
          {
            switch (fixP->fx_r_type)
              {
              case rs_align:
                ri.r_index = -2;
                ri.r_pcrel = 1;
                ri.r_length = fixP->fx_size - 1;
                break;
              case rs_org:
                ri.r_index = -2;
                ri.r_pcrel = 0;
                break;
              case rs_fill:
                ri.r_index = -1;
                break;
              default:
                abort ();
              }
            ri.r_extern = 0;
          }
        else if (linkrelax || !S_IS_DEFINED(symbolP)) {
                ri.r_extern = 1;
                ri.r_index = symbolP->sy_number;
        } else {
                ri.r_extern = 0;
                ri.r_index = S_GET_TYPE(symbolP);
        }
        
        /* Output the relocation information in machine-dependent form. */
        md_ri_to_chars(where, &ri);
        
        return;
} /* tc_bout_fix_to_chars() */

#endif /* OBJ_AOUT or OBJ_BOUT */

/* Align an address by rounding it up to the specified boundary.
 */
long md_section_align(seg, addr)
segT seg;
long addr;              /* Address to be rounded up */
{
        return((addr + (1 << section_alignment[(int) seg]) - 1) & (-1 << section_alignment[(int) seg]));
} /* md_section_align() */

#ifdef OBJ_COFF
void tc_headers_hook(headers)
object_headers *headers;
{
        /* FIXME: remove this line */ /*        unsigned short arch_flag = 0; */
        
        if (iclasses_seen == I_BASE){
                headers->filehdr.f_flags |= F_I960CORE;
        } else if (iclasses_seen & I_CX){
                headers->filehdr.f_flags |= F_I960CA;
        } else if (iclasses_seen & I_MIL){
                headers->filehdr.f_flags |= F_I960MC;
        } else if (iclasses_seen & (I_DEC|I_FP)){
                headers->filehdr.f_flags |= F_I960KB;
        } else {
                headers->filehdr.f_flags |= F_I960KA;
        } /* set arch flag */
        
        if (flagseen['R']) {
                headers->filehdr.f_magic = I960RWMAGIC;
                headers->aouthdr.magic = OMAGIC;
        } else {
                headers->filehdr.f_magic = I960ROMAGIC;
                headers->aouthdr.magic = NMAGIC;
        } /* set magic numbers */
        
        return;
} /* tc_headers_hook() */
#endif /* OBJ_COFF */

/*
 * Things going on here:
 *
 * For bout, We need to assure a couple of simplifying
 * assumptions about leafprocs for the linker: the leafproc
 * entry symbols will be defined in the same assembly in
 * which they're declared with the '.leafproc' directive;
 * and if a leafproc has both 'call' and 'bal' entry points
 * they are both global or both local.
 *
 * For coff, the call symbol has a second aux entry that
 * contains the bal entry point.  The bal symbol becomes a
 * label.
 *
 * For coff representation, the call symbol has a second aux entry that
 * contains the bal entry point.  The bal symbol becomes a label.
 *
 */

void tc_crawl_symbol_chain(headers)
object_headers *headers;
{
        symbolS *symbolP;
        
        for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next(symbolP)) {
#ifdef OBJ_COFF
                if (TC_S_IS_SYSPROC(symbolP)) {
                        /* second aux entry already contains the sysproc number */
                        S_SET_NUMBER_AUXILIARY(symbolP, 2);
                        S_SET_STORAGE_CLASS(symbolP, C_SCALL);
                        S_SET_DATA_TYPE(symbolP, S_GET_DATA_TYPE(symbolP) | (DT_FCN << N_BTSHFT));
                        continue;
                } /* rewrite sysproc */
#endif /* OBJ_COFF */
                
                if (!TC_S_IS_BALNAME(symbolP) && !TC_S_IS_CALLNAME(symbolP)) {
                        continue;
                }  /* Not a leafproc symbol */
                
                if (!S_IS_DEFINED(symbolP)) {
                        as_bad("leafproc symbol '%s' undefined", S_GET_NAME(symbolP));
                } /* undefined leaf */
                
                if (TC_S_IS_CALLNAME(symbolP)) {
                        symbolS *balP = tc_get_bal_of_call(symbolP);
                        if (S_IS_EXTERNAL(symbolP) != S_IS_EXTERNAL(balP)) {
                                S_SET_EXTERNAL(symbolP);
                                S_SET_EXTERNAL(balP);
                                as_warn("Warning: making leafproc entries %s and %s both global\n",
                                        S_GET_NAME(symbolP), S_GET_NAME(balP));
                        } /* externality mismatch */
                } /* if callname */
        } /* walk the symbol chain */
        
        return;
} /* tc_crawl_symbol_chain() */

/*
 * For aout or bout, the bal immediately follows the call.
 *
 * For coff, we cheat and store a pointer to the bal symbol
 * in the second aux entry of the call.
 */

void tc_set_bal_of_call(callP, balP)
symbolS *callP;
symbolS *balP;
{
        know(TC_S_IS_CALLNAME(callP));
        know(TC_S_IS_BALNAME(balP));
        
#ifdef OBJ_COFF
        
        callP->sy_symbol.ost_auxent[1].x_bal.x_balntry = (int) balP;
        S_SET_NUMBER_AUXILIARY(callP,2);
        
#elif defined(OBJ_AOUT) || defined(OBJ_BOUT)
        
        /* If the 'bal' entry doesn't immediately follow the 'call'
         * symbol, unlink it from the symbol list and re-insert it.
         */
        if (symbol_next(callP) != balP) {
                symbol_remove(balP, &symbol_rootP, &symbol_lastP);
                symbol_append(balP, callP, &symbol_rootP, &symbol_lastP);
        } /* if not in order */
        
#else
        (as yet unwritten.);
#endif /* switch on OBJ_FORMAT */
        
        return;
} /* tc_set_bal_of_call() */

char *_tc_get_bal_of_call(callP)
symbolS *callP;
{
        symbolS *retval;
        
        know(TC_S_IS_CALLNAME(callP));
        
#ifdef OBJ_COFF
        retval = (symbolS *) (callP->sy_symbol.ost_auxent[1].x_bal.x_balntry);
#elif defined(OBJ_AOUT) || defined(OBJ_BOUT)
        retval = symbol_next(callP);
#else
        (as yet unwritten.);
#endif /* switch on OBJ_FORMAT */
        
        know(TC_S_IS_BALNAME(retval));
        return((char *) retval);
} /* _tc_get_bal_of_call() */

void tc_coff_symbol_emit_hook(symbolP)
symbolS *symbolP;
{
        if (TC_S_IS_CALLNAME(symbolP)) {
#ifdef OBJ_COFF
                symbolS *balP = tc_get_bal_of_call(symbolP);
                
                /* second aux entry contains the bal entry point */
                /*              S_SET_NUMBER_AUXILIARY(symbolP, 2); */
                symbolP->sy_symbol.ost_auxent[1].x_bal.x_balntry = S_GET_VALUE(balP);
                S_SET_STORAGE_CLASS(symbolP, (!SF_GET_LOCAL(symbolP) ? C_LEAFEXT : C_LEAFSTAT));
                S_SET_DATA_TYPE(symbolP, S_GET_DATA_TYPE(symbolP) | (DT_FCN << N_BTSHFT));
                /* fix up the bal symbol */
                S_SET_STORAGE_CLASS(balP, C_LABEL);
#endif /* OBJ_COFF */
        } /* only on calls */
        
        return;
} /* tc_coff_symbol_emit_hook() */

void
i960_handle_align (fragp)
     fragS *fragp;
{
  fixS *fixp;
  segT old_seg = now_seg, this_seg;
  int old_subseg = now_subseg;
  int pad_size;
  extern struct frag *text_last_frag, *data_last_frag;

  if (!linkrelax)
    return;

  /* The text section "ends" with another alignment reloc, to which we
     aren't adding padding.  */
  if (fragp->fr_next == text_last_frag
      || fragp->fr_next == data_last_frag)
    {
      return;
    }

  /* alignment directive */
  fixp = fix_new (fragp, fragp->fr_fix, fragp->fr_offset, 0, 0, 0, 0,
                  (int) fragp->fr_type);
}

/*
 * Local Variables:
 * comment-column: 0
 * fill-column: 131
 * End:
 */

/* end of tc-i960.c */