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 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));
267 /* Promote small integer types to int. */
268 switch (TYPE_CODE (arg_type))
273 case TYPE_CODE_RANGE:
275 if (TYPE_LENGTH (arg_type) < 4)
277 arg_type = builtin_type (gdbarch)->builtin_int32;
278 arg = value_cast (arg_type, arg);
283 /* FIXME: Handle structures. */
285 contents = (gdb_byte *) value_contents (arg);
286 len = TYPE_LENGTH (arg_type);
287 val = extract_unsigned_integer (contents, len, byte_order);
289 /* First num_arg_regs parameters are passed by registers,
290 and the rest are passed on the stack. */
291 if (i < num_arg_regs)
292 regcache_cooked_write_unsigned (regcache, first_arg_reg + i, val);
295 write_memory (sp, (void *) &val, len);
300 /* Update stack pointer. */
301 regcache_cooked_write_signed (regcache, SIM_LM32_SP_REGNUM, sp);
303 /* Return adjusted stack pointer. */
307 /* Extract return value after calling a function in the inferior. */
310 lm32_extract_return_value (struct type *type, struct regcache *regcache,
313 struct gdbarch *gdbarch = get_regcache_arch (regcache);
314 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
316 CORE_ADDR return_buffer;
318 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
319 && TYPE_CODE (type) != TYPE_CODE_UNION
320 && TYPE_CODE (type) != TYPE_CODE_ARRAY && TYPE_LENGTH (type) <= 4)
322 /* Return value is returned in a single register. */
323 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
324 store_unsigned_integer (valbuf, TYPE_LENGTH (type), byte_order, l);
326 else if ((TYPE_CODE (type) == TYPE_CODE_INT) && (TYPE_LENGTH (type) == 8))
328 /* 64-bit values are returned in a register pair. */
329 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
330 memcpy (valbuf, &l, 4);
331 regcache_cooked_read_unsigned (regcache, SIM_LM32_R2_REGNUM, &l);
332 memcpy (valbuf + 4, &l, 4);
336 /* Aggregate types greater than a single register are returned
337 in memory. FIXME: Unless they are only 2 regs?. */
338 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
340 read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
344 /* Write into appropriate registers a function return value of type
345 TYPE, given in virtual format. */
347 lm32_store_return_value (struct type *type, struct regcache *regcache,
348 const gdb_byte *valbuf)
350 struct gdbarch *gdbarch = get_regcache_arch (regcache);
351 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
353 int len = TYPE_LENGTH (type);
357 val = extract_unsigned_integer (valbuf, len, byte_order);
358 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
362 val = extract_unsigned_integer (valbuf, 4, byte_order);
363 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
364 val = extract_unsigned_integer (valbuf + 4, len - 4, byte_order);
365 regcache_cooked_write_unsigned (regcache, SIM_LM32_R2_REGNUM, val);
368 error (_("lm32_store_return_value: type length too large."));
371 /* Determine whether a functions return value is in a register or memory. */
372 static enum return_value_convention
373 lm32_return_value (struct gdbarch *gdbarch, struct value *function,
374 struct type *valtype, struct regcache *regcache,
375 gdb_byte *readbuf, const gdb_byte *writebuf)
377 enum type_code code = TYPE_CODE (valtype);
379 if (code == TYPE_CODE_STRUCT
380 || code == TYPE_CODE_UNION
381 || code == TYPE_CODE_ARRAY || TYPE_LENGTH (valtype) > 8)
382 return RETURN_VALUE_STRUCT_CONVENTION;
385 lm32_extract_return_value (valtype, regcache, readbuf);
387 lm32_store_return_value (valtype, regcache, writebuf);
389 return RETURN_VALUE_REGISTER_CONVENTION;
393 lm32_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
395 return frame_unwind_register_unsigned (next_frame, SIM_LM32_PC_REGNUM);
399 lm32_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
401 return frame_unwind_register_unsigned (next_frame, SIM_LM32_SP_REGNUM);
404 static struct frame_id
405 lm32_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
407 CORE_ADDR sp = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
409 return frame_id_build (sp, get_frame_pc (this_frame));
412 /* Put here the code to store, into fi->saved_regs, the addresses of
413 the saved registers of frame described by FRAME_INFO. This
414 includes special registers such as pc and fp saved in special ways
415 in the stack frame. sp is even more special: the address we return
416 for it IS the sp for the next frame. */
418 static struct lm32_frame_cache *
419 lm32_frame_cache (struct frame_info *this_frame, void **this_prologue_cache)
421 CORE_ADDR current_pc;
424 struct lm32_frame_cache *info;
427 if ((*this_prologue_cache))
428 return (*this_prologue_cache);
430 info = FRAME_OBSTACK_ZALLOC (struct lm32_frame_cache);
431 (*this_prologue_cache) = info;
432 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
434 info->pc = get_frame_func (this_frame);
435 current_pc = get_frame_pc (this_frame);
436 lm32_analyze_prologue (get_frame_arch (this_frame),
437 info->pc, current_pc, info);
439 /* Compute the frame's base, and the previous frame's SP. */
440 this_base = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
441 prev_sp = this_base + info->size;
442 info->base = this_base;
444 /* Convert callee save offsets into addresses. */
445 for (i = 0; i < gdbarch_num_regs (get_frame_arch (this_frame)) - 1; i++)
447 if (trad_frame_addr_p (info->saved_regs, i))
448 info->saved_regs[i].addr = this_base + info->saved_regs[i].addr;
451 /* The call instruction moves the caller's PC in the callee's RA register.
452 Since this is an unwind, do the reverse. Copy the location of RA register
453 into PC (the address / regnum) so that a request for PC will be
454 converted into a request for the RA register. */
455 info->saved_regs[SIM_LM32_PC_REGNUM] = info->saved_regs[SIM_LM32_RA_REGNUM];
457 /* The previous frame's SP needed to be computed. Save the computed
459 trad_frame_set_value (info->saved_regs, SIM_LM32_SP_REGNUM, prev_sp);
465 lm32_frame_this_id (struct frame_info *this_frame, void **this_cache,
466 struct frame_id *this_id)
468 struct lm32_frame_cache *cache = lm32_frame_cache (this_frame, this_cache);
470 /* This marks the outermost frame. */
471 if (cache->base == 0)
474 (*this_id) = frame_id_build (cache->base, cache->pc);
477 static struct value *
478 lm32_frame_prev_register (struct frame_info *this_frame,
479 void **this_prologue_cache, int regnum)
481 struct lm32_frame_cache *info;
483 info = lm32_frame_cache (this_frame, this_prologue_cache);
484 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
487 static const struct frame_unwind lm32_frame_unwind = {
489 default_frame_unwind_stop_reason,
491 lm32_frame_prev_register,
493 default_frame_sniffer
497 lm32_frame_base_address (struct frame_info *this_frame, void **this_cache)
499 struct lm32_frame_cache *info = lm32_frame_cache (this_frame, this_cache);
504 static const struct frame_base lm32_frame_base = {
506 lm32_frame_base_address,
507 lm32_frame_base_address,
508 lm32_frame_base_address
512 lm32_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
514 /* Align to the size of an instruction (so that they can safely be
515 pushed onto the stack. */
519 static struct gdbarch *
520 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
522 struct gdbarch *gdbarch;
523 struct gdbarch_tdep *tdep;
525 /* If there is already a candidate, use it. */
526 arches = gdbarch_list_lookup_by_info (arches, &info);
528 return arches->gdbarch;
530 /* None found, create a new architecture from the information provided. */
531 tdep = XMALLOC (struct gdbarch_tdep);
532 gdbarch = gdbarch_alloc (&info, tdep);
535 set_gdbarch_short_bit (gdbarch, 16);
536 set_gdbarch_int_bit (gdbarch, 32);
537 set_gdbarch_long_bit (gdbarch, 32);
538 set_gdbarch_long_long_bit (gdbarch, 64);
539 set_gdbarch_float_bit (gdbarch, 32);
540 set_gdbarch_double_bit (gdbarch, 64);
541 set_gdbarch_long_double_bit (gdbarch, 64);
542 set_gdbarch_ptr_bit (gdbarch, 32);
545 set_gdbarch_num_regs (gdbarch, SIM_LM32_NUM_REGS);
546 set_gdbarch_sp_regnum (gdbarch, SIM_LM32_SP_REGNUM);
547 set_gdbarch_pc_regnum (gdbarch, SIM_LM32_PC_REGNUM);
548 set_gdbarch_register_name (gdbarch, lm32_register_name);
549 set_gdbarch_register_type (gdbarch, lm32_register_type);
550 set_gdbarch_cannot_store_register (gdbarch, lm32_cannot_store_register);
553 set_gdbarch_skip_prologue (gdbarch, lm32_skip_prologue);
554 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
555 set_gdbarch_decr_pc_after_break (gdbarch, 0);
556 set_gdbarch_frame_args_skip (gdbarch, 0);
558 /* Frame unwinding. */
559 set_gdbarch_frame_align (gdbarch, lm32_frame_align);
560 frame_base_set_default (gdbarch, &lm32_frame_base);
561 set_gdbarch_unwind_pc (gdbarch, lm32_unwind_pc);
562 set_gdbarch_unwind_sp (gdbarch, lm32_unwind_sp);
563 set_gdbarch_dummy_id (gdbarch, lm32_dummy_id);
564 frame_unwind_append_unwinder (gdbarch, &lm32_frame_unwind);
567 set_gdbarch_breakpoint_from_pc (gdbarch, lm32_breakpoint_from_pc);
568 set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
570 /* Calling functions in the inferior. */
571 set_gdbarch_push_dummy_call (gdbarch, lm32_push_dummy_call);
572 set_gdbarch_return_value (gdbarch, lm32_return_value);
574 /* Instruction disassembler. */
575 set_gdbarch_print_insn (gdbarch, print_insn_lm32);
577 lm32_add_reggroups (gdbarch);
578 set_gdbarch_register_reggroup_p (gdbarch, lm32_register_reggroup_p);
583 /* -Wmissing-prototypes */
584 extern initialize_file_ftype _initialize_lm32_tdep;
587 _initialize_lm32_tdep (void)
589 register_gdbarch_init (bfd_arch_lm32, lm32_gdbarch_init);