1 /* Target-dependent code for Lattice Mico32 processor, for GDB.
2 Contributed by Jon Beniston <jon@beniston.com>
4 Copyright (C) 2009, 2010 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 prologue. */
183 /* Return PC of first non prologue instruction, for the function at the
184 specified address. */
187 lm32_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
189 CORE_ADDR func_addr, limit_pc;
190 struct symtab_and_line sal;
191 struct lm32_frame_cache frame_info;
192 struct trad_frame_saved_reg saved_regs[SIM_LM32_NUM_REGS];
194 /* See if we can determine the end of the prologue via the symbol table.
195 If so, then return either PC, or the PC after the prologue, whichever
197 if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
199 CORE_ADDR post_prologue_pc
200 = skip_prologue_using_sal (gdbarch, func_addr);
201 if (post_prologue_pc != 0)
202 return max (pc, post_prologue_pc);
205 /* Can't determine prologue from the symbol table, need to examine
208 /* Find an upper limit on the function prologue using the debug
209 information. If the debug information could not be used to provide
210 that bound, then use an arbitrary large number as the upper bound. */
211 limit_pc = skip_prologue_using_sal (gdbarch, pc);
213 limit_pc = pc + 100; /* Magic. */
215 frame_info.saved_regs = saved_regs;
216 return lm32_analyze_prologue (gdbarch, pc, limit_pc, &frame_info);
219 /* Create a breakpoint instruction. */
221 static const gdb_byte *
222 lm32_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr,
225 static const gdb_byte breakpoint[4] = { OP_RAISE << 2, 0, 0, 2 };
227 *lenptr = sizeof (breakpoint);
231 /* Setup registers and stack for faking a call to a function in the
235 lm32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
236 struct regcache *regcache, CORE_ADDR bp_addr,
237 int nargs, struct value **args, CORE_ADDR sp,
238 int struct_return, CORE_ADDR struct_addr)
240 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
241 int first_arg_reg = SIM_LM32_R1_REGNUM;
242 int num_arg_regs = 8;
245 /* Set the return address. */
246 regcache_cooked_write_signed (regcache, SIM_LM32_RA_REGNUM, bp_addr);
248 /* If we're returning a large struct, a pointer to the address to
249 store it at is passed as a first hidden parameter. */
252 regcache_cooked_write_unsigned (regcache, first_arg_reg, struct_addr);
258 /* Setup parameters. */
259 for (i = 0; i < nargs; i++)
261 struct value *arg = args[i];
262 struct type *arg_type = check_typedef (value_type (arg));
269 /* Promote small integer types to int. */
270 switch (TYPE_CODE (arg_type))
275 case TYPE_CODE_RANGE:
277 if (TYPE_LENGTH (arg_type) < 4)
279 arg_type = builtin_type (gdbarch)->builtin_int32;
280 arg = value_cast (arg_type, arg);
285 /* FIXME: Handle structures. */
287 contents = (gdb_byte *) value_contents (arg);
288 len = TYPE_LENGTH (arg_type);
289 val = extract_unsigned_integer (contents, len, byte_order);
291 /* First num_arg_regs parameters are passed by registers,
292 and the rest are passed on the stack. */
293 if (i < num_arg_regs)
294 regcache_cooked_write_unsigned (regcache, first_arg_reg + i, val);
297 write_memory (sp, (void *) &val, len);
302 /* Update stack pointer. */
303 regcache_cooked_write_signed (regcache, SIM_LM32_SP_REGNUM, sp);
305 /* Return adjusted stack pointer. */
309 /* Extract return value after calling a function in the inferior. */
312 lm32_extract_return_value (struct type *type, struct regcache *regcache,
315 struct gdbarch *gdbarch = get_regcache_arch (regcache);
316 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
319 CORE_ADDR return_buffer;
321 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
322 && TYPE_CODE (type) != TYPE_CODE_UNION
323 && TYPE_CODE (type) != TYPE_CODE_ARRAY && TYPE_LENGTH (type) <= 4)
325 /* Return value is returned in a single register. */
326 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
327 store_unsigned_integer (valbuf, TYPE_LENGTH (type), byte_order, l);
329 else if ((TYPE_CODE (type) == TYPE_CODE_INT) && (TYPE_LENGTH (type) == 8))
331 /* 64-bit values are returned in a register pair. */
332 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
333 memcpy (valbuf, &l, 4);
334 regcache_cooked_read_unsigned (regcache, SIM_LM32_R2_REGNUM, &l);
335 memcpy (valbuf + 4, &l, 4);
339 /* Aggregate types greater than a single register are returned in memory.
340 FIXME: Unless they are only 2 regs?. */
341 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
343 read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
347 /* Write into appropriate registers a function return value of type
348 TYPE, given in virtual format. */
350 lm32_store_return_value (struct type *type, struct regcache *regcache,
351 const gdb_byte *valbuf)
353 struct gdbarch *gdbarch = get_regcache_arch (regcache);
354 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
356 int len = TYPE_LENGTH (type);
360 val = extract_unsigned_integer (valbuf, len, byte_order);
361 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
365 val = extract_unsigned_integer (valbuf, 4, byte_order);
366 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
367 val = extract_unsigned_integer (valbuf + 4, len - 4, byte_order);
368 regcache_cooked_write_unsigned (regcache, SIM_LM32_R2_REGNUM, val);
371 error (_("lm32_store_return_value: type length too large."));
374 /* Determine whether a functions return value is in a register or memory. */
375 static enum return_value_convention
376 lm32_return_value (struct gdbarch *gdbarch, struct type *func_type,
377 struct type *valtype, struct regcache *regcache,
378 gdb_byte *readbuf, const gdb_byte *writebuf)
380 enum type_code code = TYPE_CODE (valtype);
382 if (code == TYPE_CODE_STRUCT
383 || code == TYPE_CODE_UNION
384 || code == TYPE_CODE_ARRAY || TYPE_LENGTH (valtype) > 8)
385 return RETURN_VALUE_STRUCT_CONVENTION;
388 lm32_extract_return_value (valtype, regcache, readbuf);
390 lm32_store_return_value (valtype, regcache, writebuf);
392 return RETURN_VALUE_REGISTER_CONVENTION;
396 lm32_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
398 return frame_unwind_register_unsigned (next_frame, SIM_LM32_PC_REGNUM);
402 lm32_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
404 return frame_unwind_register_unsigned (next_frame, SIM_LM32_SP_REGNUM);
407 static struct frame_id
408 lm32_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
410 CORE_ADDR sp = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
412 return frame_id_build (sp, get_frame_pc (this_frame));
415 /* Put here the code to store, into fi->saved_regs, the addresses of
416 the saved registers of frame described by FRAME_INFO. This
417 includes special registers such as pc and fp saved in special ways
418 in the stack frame. sp is even more special: the address we return
419 for it IS the sp for the next frame. */
421 static struct lm32_frame_cache *
422 lm32_frame_cache (struct frame_info *this_frame, void **this_prologue_cache)
424 CORE_ADDR prologue_pc;
425 CORE_ADDR current_pc;
428 struct lm32_frame_cache *info;
430 unsigned long instruction;
436 if ((*this_prologue_cache))
437 return (*this_prologue_cache);
439 info = FRAME_OBSTACK_ZALLOC (struct lm32_frame_cache);
440 (*this_prologue_cache) = info;
441 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
443 info->pc = get_frame_func (this_frame);
444 current_pc = get_frame_pc (this_frame);
445 lm32_analyze_prologue (get_frame_arch (this_frame),
446 info->pc, current_pc, info);
448 /* Compute the frame's base, and the previous frame's SP. */
449 this_base = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
450 prev_sp = this_base + info->size;
451 info->base = this_base;
453 /* Convert callee save offsets into addresses. */
454 for (i = 0; i < gdbarch_num_regs (get_frame_arch (this_frame)) - 1; i++)
456 if (trad_frame_addr_p (info->saved_regs, i))
457 info->saved_regs[i].addr = this_base + info->saved_regs[i].addr;
460 /* The call instruction moves the caller's PC in the callee's RA register.
461 Since this is an unwind, do the reverse. Copy the location of RA register
462 into PC (the address / regnum) so that a request for PC will be
463 converted into a request for the RA register. */
464 info->saved_regs[SIM_LM32_PC_REGNUM] = info->saved_regs[SIM_LM32_RA_REGNUM];
466 /* The previous frame's SP needed to be computed. Save the computed value. */
467 trad_frame_set_value (info->saved_regs, SIM_LM32_SP_REGNUM, prev_sp);
473 lm32_frame_this_id (struct frame_info *this_frame, void **this_cache,
474 struct frame_id *this_id)
476 struct lm32_frame_cache *cache = lm32_frame_cache (this_frame, this_cache);
478 /* This marks the outermost frame. */
479 if (cache->base == 0)
482 (*this_id) = frame_id_build (cache->base, cache->pc);
485 static struct value *
486 lm32_frame_prev_register (struct frame_info *this_frame,
487 void **this_prologue_cache, int regnum)
489 struct lm32_frame_cache *info;
491 info = lm32_frame_cache (this_frame, this_prologue_cache);
492 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
495 static const struct frame_unwind lm32_frame_unwind = {
498 lm32_frame_prev_register,
500 default_frame_sniffer
504 lm32_frame_base_address (struct frame_info *this_frame, void **this_cache)
506 struct lm32_frame_cache *info = lm32_frame_cache (this_frame, this_cache);
511 static const struct frame_base lm32_frame_base = {
513 lm32_frame_base_address,
514 lm32_frame_base_address,
515 lm32_frame_base_address
519 lm32_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
521 /* Align to the size of an instruction (so that they can safely be
522 pushed onto the stack. */
526 static struct gdbarch *
527 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
529 struct gdbarch *gdbarch;
530 struct gdbarch_tdep *tdep;
532 /* If there is already a candidate, use it. */
533 arches = gdbarch_list_lookup_by_info (arches, &info);
535 return arches->gdbarch;
537 /* None found, create a new architecture from the information provided. */
538 tdep = XMALLOC (struct gdbarch_tdep);
539 gdbarch = gdbarch_alloc (&info, tdep);
542 set_gdbarch_short_bit (gdbarch, 16);
543 set_gdbarch_int_bit (gdbarch, 32);
544 set_gdbarch_long_bit (gdbarch, 32);
545 set_gdbarch_long_long_bit (gdbarch, 64);
546 set_gdbarch_float_bit (gdbarch, 32);
547 set_gdbarch_double_bit (gdbarch, 64);
548 set_gdbarch_long_double_bit (gdbarch, 64);
549 set_gdbarch_ptr_bit (gdbarch, 32);
552 set_gdbarch_num_regs (gdbarch, SIM_LM32_NUM_REGS);
553 set_gdbarch_sp_regnum (gdbarch, SIM_LM32_SP_REGNUM);
554 set_gdbarch_pc_regnum (gdbarch, SIM_LM32_PC_REGNUM);
555 set_gdbarch_register_name (gdbarch, lm32_register_name);
556 set_gdbarch_register_type (gdbarch, lm32_register_type);
557 set_gdbarch_cannot_store_register (gdbarch, lm32_cannot_store_register);
560 set_gdbarch_skip_prologue (gdbarch, lm32_skip_prologue);
561 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
562 set_gdbarch_decr_pc_after_break (gdbarch, 0);
563 set_gdbarch_frame_args_skip (gdbarch, 0);
565 /* Frame unwinding. */
566 set_gdbarch_frame_align (gdbarch, lm32_frame_align);
567 frame_base_set_default (gdbarch, &lm32_frame_base);
568 set_gdbarch_unwind_pc (gdbarch, lm32_unwind_pc);
569 set_gdbarch_unwind_sp (gdbarch, lm32_unwind_sp);
570 set_gdbarch_dummy_id (gdbarch, lm32_dummy_id);
571 frame_unwind_append_unwinder (gdbarch, &lm32_frame_unwind);
574 set_gdbarch_breakpoint_from_pc (gdbarch, lm32_breakpoint_from_pc);
575 set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
577 /* Calling functions in the inferior. */
578 set_gdbarch_push_dummy_call (gdbarch, lm32_push_dummy_call);
579 set_gdbarch_return_value (gdbarch, lm32_return_value);
581 /* Instruction disassembler. */
582 set_gdbarch_print_insn (gdbarch, print_insn_lm32);
584 lm32_add_reggroups (gdbarch);
585 set_gdbarch_register_reggroup_p (gdbarch, lm32_register_reggroup_p);
591 _initialize_lm32_tdep (void)
593 register_gdbarch_init (bfd_arch_lm32, lm32_gdbarch_init);