libyasm/bc-org.c

   1 /*
   2  * ORG bytecode
   3  *
   4  *  Copyright (C) 2005-2007  Peter Johnson
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER CONTRIBUTORS ``AS IS''
  16  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR OTHER CONTRIBUTORS BE
  19  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  20  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  21  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  24  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  25  * POSSIBILITY OF SUCH DAMAGE.
  26  */
  27 #include "util.h"
  28
  29 #include "libyasm-stdint.h"
  30 #include "coretype.h"
  31 #include "file.h"
  32
  33 #include "errwarn.h"
  34 #include "intnum.h"
  35 #include "expr.h"
  36 #include "value.h"
  37
  38 #include "bytecode.h"
  39
  40
  41 typedef struct bytecode_org {
  42     unsigned long start;        /* target starting offset within section */
  43     unsigned long fill;         /* fill value */
  44 } bytecode_org;
  45
  46 static void bc_org_destroy(void *contents);
  47 static void bc_org_print(const void *contents, FILE *f, int indent_level);
  48 static void bc_org_finalize(yasm_bytecode *bc, yasm_bytecode *prev_bc);
  49 static int bc_org_calc_len(yasm_bytecode *bc, yasm_bc_add_span_func add_span,
  50                            void *add_span_data);
  51 static int bc_org_expand(yasm_bytecode *bc, int span, long old_val,
  52                          long new_val, /*@out@*/ long *neg_thres,
  53                          /*@out@*/ long *pos_thres);
  54 static int bc_org_tobytes(yasm_bytecode *bc, unsigned char **bufp,
  55                           unsigned char *bufstart, void *d,
  56                           yasm_output_value_func output_value,
  57                           /*@null@*/ yasm_output_reloc_func output_reloc);
  58
  59 static const yasm_bytecode_callback bc_org_callback = {
  60     bc_org_destroy,
  61     bc_org_print,
  62     bc_org_finalize,
  63     NULL,
  64     bc_org_calc_len,
  65     bc_org_expand,
  66     bc_org_tobytes,
  67     YASM_BC_SPECIAL_OFFSET
  68 };
  69
  70
  71 static void
  72 bc_org_destroy(void *contents)
  73 {
  74     yasm_xfree(contents);
  75 }
  76
  77 static void
  78 bc_org_print(const void *contents, FILE *f, int indent_level)
  79 {
  80     const bytecode_org *org = (const bytecode_org *)contents;
  81     fprintf(f, "%*s_Org_\n", indent_level, "");
  82     fprintf(f, "%*sStart=%lu\n", indent_level, "", org->start);
  83 }
  84
  85 static void
  86 bc_org_finalize(yasm_bytecode *bc, yasm_bytecode *prev_bc)
  87 {
  88 }
  89
  90 static int
  91 bc_org_calc_len(yasm_bytecode *bc, yasm_bc_add_span_func add_span,
  92                 void *add_span_data)
  93 {
  94     bytecode_org *org = (bytecode_org *)bc->contents;
  95     long neg_thres = 0;
  96     long pos_thres = org->start;
  97
  98     if (bc_org_expand(bc, 0, 0, (long)bc->offset, &neg_thres, &pos_thres) < 0)
  99         return -1;
 100
 101     return 0;
 102 }
 103
 104 static int
 105 bc_org_expand(yasm_bytecode *bc, int span, long old_val, long new_val,
 106               /*@out@*/ long *neg_thres, /*@out@*/ long *pos_thres)
 107 {
 108     bytecode_org *org = (bytecode_org *)bc->contents;
 109
 110     /* Check for overrun */
 111     if ((unsigned long)new_val > org->start) {
 112         yasm_error_set(YASM_ERROR_GENERAL,
 113                        N_("ORG overlap with already existing data"));
 114         return -1;
 115     }
 116
 117     /* Generate space to start offset */
 118     bc->len = org->start - new_val;
 119     return 1;
 120 }
 121
 122 static int
 123 bc_org_tobytes(yasm_bytecode *bc, unsigned char **bufp,
 124                unsigned char *bufstart, void *d,
 125                yasm_output_value_func output_value,
 126                /*@unused@*/ yasm_output_reloc_func output_reloc)
 127 {
 128     bytecode_org *org = (bytecode_org *)bc->contents;
 129     unsigned long len, i;
 130
 131     /* Sanity check for overrun */
 132     if (bc->offset > org->start) {
 133         yasm_error_set(YASM_ERROR_GENERAL,
 134                        N_("ORG overlap with already existing data"));
 135         return 1;
 136     }
 137     len = org->start - bc->offset;
 138     for (i=0; i<len; i++)
 139         YASM_WRITE_8(*bufp, org->fill);     /* XXX: handle more than 8 bit? */
 140     return 0;
 141 }
 142
 143 yasm_bytecode *
 144 yasm_bc_create_org(unsigned long start, unsigned long fill, unsigned long line)
 145 {
 146     bytecode_org *org = yasm_xmalloc(sizeof(bytecode_org));
 147
 148     org->start = start;
 149     org->fill = fill;
 150
 151     return yasm_bc_create_common(&bc_org_callback, org, line);
 152 }