1 /* Target-dependent code for Lattice Mico32 processor, for GDB.
2 Contributed by Jon Beniston <jon@beniston.com>
4 Copyright (C) 2009-2012 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "frame-unwind.h"
24 #include "frame-base.h"
30 #include "gdb/sim-lm32.h"
31 #include "gdb/callback.h"
32 #include "gdb/remote-sim.h"
33 #include "sim-regno.h"
34 #include "arch-utils.h"
36 #include "trad-frame.h"
37 #include "reggroups.h"
38 #include "opcodes/lm32-desc.h"
40 #include "gdb_string.h"
42 /* Macros to extract fields from an instruction. */
43 #define LM32_OPCODE(insn) ((insn >> 26) & 0x3f)
44 #define LM32_REG0(insn) ((insn >> 21) & 0x1f)
45 #define LM32_REG1(insn) ((insn >> 16) & 0x1f)
46 #define LM32_REG2(insn) ((insn >> 11) & 0x1f)
47 #define LM32_IMM16(insn) ((((long)insn & 0xffff) << 16) >> 16)
51 /* gdbarch target dependent data here. Currently unused for LM32. */
54 struct lm32_frame_cache
56 /* The frame's base. Used when constructing a frame ID. */
61 /* Table indicating the location of each and every register. */
62 struct trad_frame_saved_reg *saved_regs;
65 /* Add the available register groups. */
68 lm32_add_reggroups (struct gdbarch *gdbarch)
70 reggroup_add (gdbarch, general_reggroup);
71 reggroup_add (gdbarch, all_reggroup);
72 reggroup_add (gdbarch, system_reggroup);
75 /* Return whether a given register is in a given group. */
78 lm32_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
79 struct reggroup *group)
81 if (group == general_reggroup)
82 return ((regnum >= SIM_LM32_R0_REGNUM) && (regnum <= SIM_LM32_RA_REGNUM))
83 || (regnum == SIM_LM32_PC_REGNUM);
84 else if (group == system_reggroup)
85 return ((regnum >= SIM_LM32_EA_REGNUM) && (regnum <= SIM_LM32_BA_REGNUM))
86 || ((regnum >= SIM_LM32_EID_REGNUM) && (regnum <= SIM_LM32_IP_REGNUM));
87 return default_register_reggroup_p (gdbarch, regnum, group);
90 /* Return a name that corresponds to the given register number. */
93 lm32_register_name (struct gdbarch *gdbarch, int reg_nr)
95 static char *register_names[] = {
96 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
97 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
98 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
99 "r24", "r25", "gp", "fp", "sp", "ra", "ea", "ba",
100 "PC", "EID", "EBA", "DEBA", "IE", "IM", "IP"
103 if ((reg_nr < 0) || (reg_nr >= ARRAY_SIZE (register_names)))
106 return register_names[reg_nr];
109 /* Return type of register. */
112 lm32_register_type (struct gdbarch *gdbarch, int reg_nr)
114 return builtin_type (gdbarch)->builtin_int32;
117 /* Return non-zero if a register can't be written. */
120 lm32_cannot_store_register (struct gdbarch *gdbarch, int regno)
122 return (regno == SIM_LM32_R0_REGNUM) || (regno == SIM_LM32_EID_REGNUM);
125 /* Analyze a function's prologue. */
128 lm32_analyze_prologue (struct gdbarch *gdbarch,
129 CORE_ADDR pc, CORE_ADDR limit,
130 struct lm32_frame_cache *info)
132 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
133 unsigned long instruction;
135 /* Keep reading though instructions, until we come across an instruction
136 that isn't likely to be part of the prologue. */
138 for (; pc < limit; pc += 4)
141 /* Read an instruction. */
142 instruction = read_memory_integer (pc, 4, byte_order);
144 if ((LM32_OPCODE (instruction) == OP_SW)
145 && (LM32_REG0 (instruction) == SIM_LM32_SP_REGNUM))
147 /* Any stack displaced store is likely part of the prologue.
148 Record that the register is being saved, and the offset
150 info->saved_regs[LM32_REG1 (instruction)].addr =
151 LM32_IMM16 (instruction);
153 else if ((LM32_OPCODE (instruction) == OP_ADDI)
154 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
156 /* An add to the SP is likely to be part of the prologue.
157 Adjust stack size by whatever the instruction adds to the sp. */
158 info->size -= LM32_IMM16 (instruction);
160 else if ( /* add fp,fp,sp */
161 ((LM32_OPCODE (instruction) == OP_ADD)
162 && (LM32_REG2 (instruction) == SIM_LM32_FP_REGNUM)
163 && (LM32_REG0 (instruction) == SIM_LM32_FP_REGNUM)
164 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
166 || ((LM32_OPCODE (instruction) == OP_ADDI)
167 && (LM32_REG1 (instruction) == SIM_LM32_FP_REGNUM)
168 && (LM32_REG0 (instruction) == SIM_LM32_R0_REGNUM)))
170 /* Likely to be in the prologue for functions that require
175 /* Any other instruction is likely not to be part of the
184 /* Return PC of first non prologue instruction, for the function at the
185 specified address. */
188 lm32_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
190 CORE_ADDR func_addr, limit_pc;
191 struct symtab_and_line sal;
192 struct lm32_frame_cache frame_info;
193 struct trad_frame_saved_reg saved_regs[SIM_LM32_NUM_REGS];
195 /* See if we can determine the end of the prologue via the symbol table.
196 If so, then return either PC, or the PC after the prologue, whichever
198 if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
200 CORE_ADDR post_prologue_pc
201 = skip_prologue_using_sal (gdbarch, func_addr);
202 if (post_prologue_pc != 0)
203 return max (pc, post_prologue_pc);
206 /* Can't determine prologue from the symbol table, need to examine
209 /* Find an upper limit on the function prologue using the debug
210 information. If the debug information could not be used to provide
211 that bound, then use an arbitrary large number as the upper bound. */
212 limit_pc = skip_prologue_using_sal (gdbarch, pc);
214 limit_pc = pc + 100; /* Magic. */
216 frame_info.saved_regs = saved_regs;
217 return lm32_analyze_prologue (gdbarch, pc, limit_pc, &frame_info);
220 /* Create a breakpoint instruction. */
222 static const gdb_byte *
223 lm32_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr,
226 static const gdb_byte breakpoint[4] = { OP_RAISE << 2, 0, 0, 2 };
228 *lenptr = sizeof (breakpoint);
232 /* Setup registers and stack for faking a call to a function in the
236 lm32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
237 struct regcache *regcache, CORE_ADDR bp_addr,
238 int nargs, struct value **args, CORE_ADDR sp,
239 int struct_return, CORE_ADDR struct_addr)
241 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
242 int first_arg_reg = SIM_LM32_R1_REGNUM;
243 int num_arg_regs = 8;
246 /* Set the return address. */
247 regcache_cooked_write_signed (regcache, SIM_LM32_RA_REGNUM, bp_addr);
249 /* If we're returning a large struct, a pointer to the address to
250 store it at is passed as a first hidden parameter. */
253 regcache_cooked_write_unsigned (regcache, first_arg_reg, struct_addr);
259 /* Setup parameters. */
260 for (i = 0; i < nargs; i++)
262 struct value *arg = args[i];
263 struct type *arg_type = check_typedef (value_type (arg));
270 /* Promote small integer types to int. */
271 switch (TYPE_CODE (arg_type))
276 case TYPE_CODE_RANGE:
278 if (TYPE_LENGTH (arg_type) < 4)
280 arg_type = builtin_type (gdbarch)->builtin_int32;
281 arg = value_cast (arg_type, arg);
286 /* FIXME: Handle structures. */
288 contents = (gdb_byte *) value_contents (arg);
289 len = TYPE_LENGTH (arg_type);
290 val = extract_unsigned_integer (contents, len, byte_order);
292 /* First num_arg_regs parameters are passed by registers,
293 and the rest are passed on the stack. */
294 if (i < num_arg_regs)
295 regcache_cooked_write_unsigned (regcache, first_arg_reg + i, val);
298 write_memory (sp, (void *) &val, len);
303 /* Update stack pointer. */
304 regcache_cooked_write_signed (regcache, SIM_LM32_SP_REGNUM, sp);
306 /* Return adjusted stack pointer. */
310 /* Extract return value after calling a function in the inferior. */
313 lm32_extract_return_value (struct type *type, struct regcache *regcache,
316 struct gdbarch *gdbarch = get_regcache_arch (regcache);
317 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
320 CORE_ADDR return_buffer;
322 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
323 && TYPE_CODE (type) != TYPE_CODE_UNION
324 && TYPE_CODE (type) != TYPE_CODE_ARRAY && TYPE_LENGTH (type) <= 4)
326 /* Return value is returned in a single register. */
327 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
328 store_unsigned_integer (valbuf, TYPE_LENGTH (type), byte_order, l);
330 else if ((TYPE_CODE (type) == TYPE_CODE_INT) && (TYPE_LENGTH (type) == 8))
332 /* 64-bit values are returned in a register pair. */
333 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
334 memcpy (valbuf, &l, 4);
335 regcache_cooked_read_unsigned (regcache, SIM_LM32_R2_REGNUM, &l);
336 memcpy (valbuf + 4, &l, 4);
340 /* Aggregate types greater than a single register are returned
341 in memory. FIXME: Unless they are only 2 regs?. */
342 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
344 read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
348 /* Write into appropriate registers a function return value of type
349 TYPE, given in virtual format. */
351 lm32_store_return_value (struct type *type, struct regcache *regcache,
352 const gdb_byte *valbuf)
354 struct gdbarch *gdbarch = get_regcache_arch (regcache);
355 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
357 int len = TYPE_LENGTH (type);
361 val = extract_unsigned_integer (valbuf, len, byte_order);
362 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
366 val = extract_unsigned_integer (valbuf, 4, byte_order);
367 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
368 val = extract_unsigned_integer (valbuf + 4, len - 4, byte_order);
369 regcache_cooked_write_unsigned (regcache, SIM_LM32_R2_REGNUM, val);
372 error (_("lm32_store_return_value: type length too large."));
375 /* Determine whether a functions return value is in a register or memory. */
376 static enum return_value_convention
377 lm32_return_value (struct gdbarch *gdbarch, struct type *func_type,
378 struct type *valtype, struct regcache *regcache,
379 gdb_byte *readbuf, const gdb_byte *writebuf)
381 enum type_code code = TYPE_CODE (valtype);
383 if (code == TYPE_CODE_STRUCT
384 || code == TYPE_CODE_UNION
385 || code == TYPE_CODE_ARRAY || TYPE_LENGTH (valtype) > 8)
386 return RETURN_VALUE_STRUCT_CONVENTION;
389 lm32_extract_return_value (valtype, regcache, readbuf);
391 lm32_store_return_value (valtype, regcache, writebuf);
393 return RETURN_VALUE_REGISTER_CONVENTION;
397 lm32_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
399 return frame_unwind_register_unsigned (next_frame, SIM_LM32_PC_REGNUM);
403 lm32_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
405 return frame_unwind_register_unsigned (next_frame, SIM_LM32_SP_REGNUM);
408 static struct frame_id
409 lm32_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
411 CORE_ADDR sp = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
413 return frame_id_build (sp, get_frame_pc (this_frame));
416 /* Put here the code to store, into fi->saved_regs, the addresses of
417 the saved registers of frame described by FRAME_INFO. This
418 includes special registers such as pc and fp saved in special ways
419 in the stack frame. sp is even more special: the address we return
420 for it IS the sp for the next frame. */
422 static struct lm32_frame_cache *
423 lm32_frame_cache (struct frame_info *this_frame, void **this_prologue_cache)
425 CORE_ADDR prologue_pc;
426 CORE_ADDR current_pc;
429 struct lm32_frame_cache *info;
431 unsigned long instruction;
437 if ((*this_prologue_cache))
438 return (*this_prologue_cache);
440 info = FRAME_OBSTACK_ZALLOC (struct lm32_frame_cache);
441 (*this_prologue_cache) = info;
442 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
444 info->pc = get_frame_func (this_frame);
445 current_pc = get_frame_pc (this_frame);
446 lm32_analyze_prologue (get_frame_arch (this_frame),
447 info->pc, current_pc, info);
449 /* Compute the frame's base, and the previous frame's SP. */
450 this_base = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
451 prev_sp = this_base + info->size;
452 info->base = this_base;
454 /* Convert callee save offsets into addresses. */
455 for (i = 0; i < gdbarch_num_regs (get_frame_arch (this_frame)) - 1; i++)
457 if (trad_frame_addr_p (info->saved_regs, i))
458 info->saved_regs[i].addr = this_base + info->saved_regs[i].addr;
461 /* The call instruction moves the caller's PC in the callee's RA register.
462 Since this is an unwind, do the reverse. Copy the location of RA register
463 into PC (the address / regnum) so that a request for PC will be
464 converted into a request for the RA register. */
465 info->saved_regs[SIM_LM32_PC_REGNUM] = info->saved_regs[SIM_LM32_RA_REGNUM];
467 /* The previous frame's SP needed to be computed. Save the computed
469 trad_frame_set_value (info->saved_regs, SIM_LM32_SP_REGNUM, prev_sp);
475 lm32_frame_this_id (struct frame_info *this_frame, void **this_cache,
476 struct frame_id *this_id)
478 struct lm32_frame_cache *cache = lm32_frame_cache (this_frame, this_cache);
480 /* This marks the outermost frame. */
481 if (cache->base == 0)
484 (*this_id) = frame_id_build (cache->base, cache->pc);
487 static struct value *
488 lm32_frame_prev_register (struct frame_info *this_frame,
489 void **this_prologue_cache, int regnum)
491 struct lm32_frame_cache *info;
493 info = lm32_frame_cache (this_frame, this_prologue_cache);
494 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
497 static const struct frame_unwind lm32_frame_unwind = {
499 default_frame_unwind_stop_reason,
501 lm32_frame_prev_register,
503 default_frame_sniffer
507 lm32_frame_base_address (struct frame_info *this_frame, void **this_cache)
509 struct lm32_frame_cache *info = lm32_frame_cache (this_frame, this_cache);
514 static const struct frame_base lm32_frame_base = {
516 lm32_frame_base_address,
517 lm32_frame_base_address,
518 lm32_frame_base_address
522 lm32_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
524 /* Align to the size of an instruction (so that they can safely be
525 pushed onto the stack. */
529 static struct gdbarch *
530 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
532 struct gdbarch *gdbarch;
533 struct gdbarch_tdep *tdep;
535 /* If there is already a candidate, use it. */
536 arches = gdbarch_list_lookup_by_info (arches, &info);
538 return arches->gdbarch;
540 /* None found, create a new architecture from the information provided. */
541 tdep = XMALLOC (struct gdbarch_tdep);
542 gdbarch = gdbarch_alloc (&info, tdep);
545 set_gdbarch_short_bit (gdbarch, 16);
546 set_gdbarch_int_bit (gdbarch, 32);
547 set_gdbarch_long_bit (gdbarch, 32);
548 set_gdbarch_long_long_bit (gdbarch, 64);
549 set_gdbarch_float_bit (gdbarch, 32);
550 set_gdbarch_double_bit (gdbarch, 64);
551 set_gdbarch_long_double_bit (gdbarch, 64);
552 set_gdbarch_ptr_bit (gdbarch, 32);
555 set_gdbarch_num_regs (gdbarch, SIM_LM32_NUM_REGS);
556 set_gdbarch_sp_regnum (gdbarch, SIM_LM32_SP_REGNUM);
557 set_gdbarch_pc_regnum (gdbarch, SIM_LM32_PC_REGNUM);
558 set_gdbarch_register_name (gdbarch, lm32_register_name);
559 set_gdbarch_register_type (gdbarch, lm32_register_type);
560 set_gdbarch_cannot_store_register (gdbarch, lm32_cannot_store_register);
563 set_gdbarch_skip_prologue (gdbarch, lm32_skip_prologue);
564 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
565 set_gdbarch_decr_pc_after_break (gdbarch, 0);
566 set_gdbarch_frame_args_skip (gdbarch, 0);
568 /* Frame unwinding. */
569 set_gdbarch_frame_align (gdbarch, lm32_frame_align);
570 frame_base_set_default (gdbarch, &lm32_frame_base);
571 set_gdbarch_unwind_pc (gdbarch, lm32_unwind_pc);
572 set_gdbarch_unwind_sp (gdbarch, lm32_unwind_sp);
573 set_gdbarch_dummy_id (gdbarch, lm32_dummy_id);
574 frame_unwind_append_unwinder (gdbarch, &lm32_frame_unwind);
577 set_gdbarch_breakpoint_from_pc (gdbarch, lm32_breakpoint_from_pc);
578 set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
580 /* Calling functions in the inferior. */
581 set_gdbarch_push_dummy_call (gdbarch, lm32_push_dummy_call);
582 set_gdbarch_return_value (gdbarch, lm32_return_value);
584 /* Instruction disassembler. */
585 set_gdbarch_print_insn (gdbarch, print_insn_lm32);
587 lm32_add_reggroups (gdbarch);
588 set_gdbarch_register_reggroup_p (gdbarch, lm32_register_reggroup_p);
594 _initialize_lm32_tdep (void)
596 register_gdbarch_init (bfd_arch_lm32, lm32_gdbarch_init);