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[deliverable/binutils-gdb.git] / gdb / lm32-tdep.c
1 /* Target-dependent code for Lattice Mico32 processor, for GDB.
2 Contributed by Jon Beniston <jon@beniston.com>
3
4 Copyright (C) 2009-2014 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
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.
12
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.
17
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/>. */
20
21 #include "defs.h"
22 #include "frame.h"
23 #include "frame-unwind.h"
24 #include "frame-base.h"
25 #include "inferior.h"
26 #include "dis-asm.h"
27 #include "symfile.h"
28 #include "remote.h"
29 #include "gdbcore.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"
35 #include "regcache.h"
36 #include "trad-frame.h"
37 #include "reggroups.h"
38 #include "opcodes/lm32-desc.h"
39
40 #include <string.h>
41
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)
48
49 struct gdbarch_tdep
50 {
51 /* gdbarch target dependent data here. Currently unused for LM32. */
52 };
53
54 struct lm32_frame_cache
55 {
56 /* The frame's base. Used when constructing a frame ID. */
57 CORE_ADDR base;
58 CORE_ADDR pc;
59 /* Size of frame. */
60 int size;
61 /* Table indicating the location of each and every register. */
62 struct trad_frame_saved_reg *saved_regs;
63 };
64
65 /* Add the available register groups. */
66
67 static void
68 lm32_add_reggroups (struct gdbarch *gdbarch)
69 {
70 reggroup_add (gdbarch, general_reggroup);
71 reggroup_add (gdbarch, all_reggroup);
72 reggroup_add (gdbarch, system_reggroup);
73 }
74
75 /* Return whether a given register is in a given group. */
76
77 static int
78 lm32_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
79 struct reggroup *group)
80 {
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);
88 }
89
90 /* Return a name that corresponds to the given register number. */
91
92 static const char *
93 lm32_register_name (struct gdbarch *gdbarch, int reg_nr)
94 {
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"
101 };
102
103 if ((reg_nr < 0) || (reg_nr >= ARRAY_SIZE (register_names)))
104 return NULL;
105 else
106 return register_names[reg_nr];
107 }
108
109 /* Return type of register. */
110
111 static struct type *
112 lm32_register_type (struct gdbarch *gdbarch, int reg_nr)
113 {
114 return builtin_type (gdbarch)->builtin_int32;
115 }
116
117 /* Return non-zero if a register can't be written. */
118
119 static int
120 lm32_cannot_store_register (struct gdbarch *gdbarch, int regno)
121 {
122 return (regno == SIM_LM32_R0_REGNUM) || (regno == SIM_LM32_EID_REGNUM);
123 }
124
125 /* Analyze a function's prologue. */
126
127 static CORE_ADDR
128 lm32_analyze_prologue (struct gdbarch *gdbarch,
129 CORE_ADDR pc, CORE_ADDR limit,
130 struct lm32_frame_cache *info)
131 {
132 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
133 unsigned long instruction;
134
135 /* Keep reading though instructions, until we come across an instruction
136 that isn't likely to be part of the prologue. */
137 info->size = 0;
138 for (; pc < limit; pc += 4)
139 {
140
141 /* Read an instruction. */
142 instruction = read_memory_integer (pc, 4, byte_order);
143
144 if ((LM32_OPCODE (instruction) == OP_SW)
145 && (LM32_REG0 (instruction) == SIM_LM32_SP_REGNUM))
146 {
147 /* Any stack displaced store is likely part of the prologue.
148 Record that the register is being saved, and the offset
149 into the stack. */
150 info->saved_regs[LM32_REG1 (instruction)].addr =
151 LM32_IMM16 (instruction);
152 }
153 else if ((LM32_OPCODE (instruction) == OP_ADDI)
154 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
155 {
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);
159 }
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))
165 /* mv fp,imm */
166 || ((LM32_OPCODE (instruction) == OP_ADDI)
167 && (LM32_REG1 (instruction) == SIM_LM32_FP_REGNUM)
168 && (LM32_REG0 (instruction) == SIM_LM32_R0_REGNUM)))
169 {
170 /* Likely to be in the prologue for functions that require
171 a frame pointer. */
172 }
173 else
174 {
175 /* Any other instruction is likely not to be part of the
176 prologue. */
177 break;
178 }
179 }
180
181 return pc;
182 }
183
184 /* Return PC of first non prologue instruction, for the function at the
185 specified address. */
186
187 static CORE_ADDR
188 lm32_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
189 {
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];
193
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
196 is greater. */
197 if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
198 {
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);
203 }
204
205 /* Can't determine prologue from the symbol table, need to examine
206 instructions. */
207
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);
212 if (limit_pc == 0)
213 limit_pc = pc + 100; /* Magic. */
214
215 frame_info.saved_regs = saved_regs;
216 return lm32_analyze_prologue (gdbarch, pc, limit_pc, &frame_info);
217 }
218
219 /* Create a breakpoint instruction. */
220
221 static const gdb_byte *
222 lm32_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr,
223 int *lenptr)
224 {
225 static const gdb_byte breakpoint[4] = { OP_RAISE << 2, 0, 0, 2 };
226
227 *lenptr = sizeof (breakpoint);
228 return breakpoint;
229 }
230
231 /* Setup registers and stack for faking a call to a function in the
232 inferior. */
233
234 static CORE_ADDR
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)
239 {
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;
243 int i;
244
245 /* Set the return address. */
246 regcache_cooked_write_signed (regcache, SIM_LM32_RA_REGNUM, bp_addr);
247
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. */
250 if (struct_return)
251 {
252 regcache_cooked_write_unsigned (regcache, first_arg_reg, struct_addr);
253 first_arg_reg++;
254 num_arg_regs--;
255 sp -= 4;
256 }
257
258 /* Setup parameters. */
259 for (i = 0; i < nargs; i++)
260 {
261 struct value *arg = args[i];
262 struct type *arg_type = check_typedef (value_type (arg));
263 gdb_byte *contents;
264 ULONGEST val;
265
266 /* Promote small integer types to int. */
267 switch (TYPE_CODE (arg_type))
268 {
269 case TYPE_CODE_INT:
270 case TYPE_CODE_BOOL:
271 case TYPE_CODE_CHAR:
272 case TYPE_CODE_RANGE:
273 case TYPE_CODE_ENUM:
274 if (TYPE_LENGTH (arg_type) < 4)
275 {
276 arg_type = builtin_type (gdbarch)->builtin_int32;
277 arg = value_cast (arg_type, arg);
278 }
279 break;
280 }
281
282 /* FIXME: Handle structures. */
283
284 contents = (gdb_byte *) value_contents (arg);
285 val = extract_unsigned_integer (contents, TYPE_LENGTH (arg_type),
286 byte_order);
287
288 /* First num_arg_regs parameters are passed by registers,
289 and the rest are passed on the stack. */
290 if (i < num_arg_regs)
291 regcache_cooked_write_unsigned (regcache, first_arg_reg + i, val);
292 else
293 {
294 write_memory (sp, (void *) &val, TYPE_LENGTH (arg_type));
295 sp -= 4;
296 }
297 }
298
299 /* Update stack pointer. */
300 regcache_cooked_write_signed (regcache, SIM_LM32_SP_REGNUM, sp);
301
302 /* Return adjusted stack pointer. */
303 return sp;
304 }
305
306 /* Extract return value after calling a function in the inferior. */
307
308 static void
309 lm32_extract_return_value (struct type *type, struct regcache *regcache,
310 gdb_byte *valbuf)
311 {
312 struct gdbarch *gdbarch = get_regcache_arch (regcache);
313 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
314 ULONGEST l;
315 CORE_ADDR return_buffer;
316
317 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
318 && TYPE_CODE (type) != TYPE_CODE_UNION
319 && TYPE_CODE (type) != TYPE_CODE_ARRAY && TYPE_LENGTH (type) <= 4)
320 {
321 /* Return value is returned in a single register. */
322 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
323 store_unsigned_integer (valbuf, TYPE_LENGTH (type), byte_order, l);
324 }
325 else if ((TYPE_CODE (type) == TYPE_CODE_INT) && (TYPE_LENGTH (type) == 8))
326 {
327 /* 64-bit values are returned in a register pair. */
328 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
329 memcpy (valbuf, &l, 4);
330 regcache_cooked_read_unsigned (regcache, SIM_LM32_R2_REGNUM, &l);
331 memcpy (valbuf + 4, &l, 4);
332 }
333 else
334 {
335 /* Aggregate types greater than a single register are returned
336 in memory. FIXME: Unless they are only 2 regs?. */
337 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
338 return_buffer = l;
339 read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
340 }
341 }
342
343 /* Write into appropriate registers a function return value of type
344 TYPE, given in virtual format. */
345 static void
346 lm32_store_return_value (struct type *type, struct regcache *regcache,
347 const gdb_byte *valbuf)
348 {
349 struct gdbarch *gdbarch = get_regcache_arch (regcache);
350 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
351 ULONGEST val;
352 int len = TYPE_LENGTH (type);
353
354 if (len <= 4)
355 {
356 val = extract_unsigned_integer (valbuf, len, byte_order);
357 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
358 }
359 else if (len <= 8)
360 {
361 val = extract_unsigned_integer (valbuf, 4, byte_order);
362 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
363 val = extract_unsigned_integer (valbuf + 4, len - 4, byte_order);
364 regcache_cooked_write_unsigned (regcache, SIM_LM32_R2_REGNUM, val);
365 }
366 else
367 error (_("lm32_store_return_value: type length too large."));
368 }
369
370 /* Determine whether a functions return value is in a register or memory. */
371 static enum return_value_convention
372 lm32_return_value (struct gdbarch *gdbarch, struct value *function,
373 struct type *valtype, struct regcache *regcache,
374 gdb_byte *readbuf, const gdb_byte *writebuf)
375 {
376 enum type_code code = TYPE_CODE (valtype);
377
378 if (code == TYPE_CODE_STRUCT
379 || code == TYPE_CODE_UNION
380 || code == TYPE_CODE_ARRAY || TYPE_LENGTH (valtype) > 8)
381 return RETURN_VALUE_STRUCT_CONVENTION;
382
383 if (readbuf)
384 lm32_extract_return_value (valtype, regcache, readbuf);
385 if (writebuf)
386 lm32_store_return_value (valtype, regcache, writebuf);
387
388 return RETURN_VALUE_REGISTER_CONVENTION;
389 }
390
391 static CORE_ADDR
392 lm32_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
393 {
394 return frame_unwind_register_unsigned (next_frame, SIM_LM32_PC_REGNUM);
395 }
396
397 static CORE_ADDR
398 lm32_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
399 {
400 return frame_unwind_register_unsigned (next_frame, SIM_LM32_SP_REGNUM);
401 }
402
403 static struct frame_id
404 lm32_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
405 {
406 CORE_ADDR sp = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
407
408 return frame_id_build (sp, get_frame_pc (this_frame));
409 }
410
411 /* Put here the code to store, into fi->saved_regs, the addresses of
412 the saved registers of frame described by FRAME_INFO. This
413 includes special registers such as pc and fp saved in special ways
414 in the stack frame. sp is even more special: the address we return
415 for it IS the sp for the next frame. */
416
417 static struct lm32_frame_cache *
418 lm32_frame_cache (struct frame_info *this_frame, void **this_prologue_cache)
419 {
420 CORE_ADDR current_pc;
421 ULONGEST prev_sp;
422 ULONGEST this_base;
423 struct lm32_frame_cache *info;
424 int i;
425
426 if ((*this_prologue_cache))
427 return (*this_prologue_cache);
428
429 info = FRAME_OBSTACK_ZALLOC (struct lm32_frame_cache);
430 (*this_prologue_cache) = info;
431 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
432
433 info->pc = get_frame_func (this_frame);
434 current_pc = get_frame_pc (this_frame);
435 lm32_analyze_prologue (get_frame_arch (this_frame),
436 info->pc, current_pc, info);
437
438 /* Compute the frame's base, and the previous frame's SP. */
439 this_base = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
440 prev_sp = this_base + info->size;
441 info->base = this_base;
442
443 /* Convert callee save offsets into addresses. */
444 for (i = 0; i < gdbarch_num_regs (get_frame_arch (this_frame)) - 1; i++)
445 {
446 if (trad_frame_addr_p (info->saved_regs, i))
447 info->saved_regs[i].addr = this_base + info->saved_regs[i].addr;
448 }
449
450 /* The call instruction moves the caller's PC in the callee's RA register.
451 Since this is an unwind, do the reverse. Copy the location of RA register
452 into PC (the address / regnum) so that a request for PC will be
453 converted into a request for the RA register. */
454 info->saved_regs[SIM_LM32_PC_REGNUM] = info->saved_regs[SIM_LM32_RA_REGNUM];
455
456 /* The previous frame's SP needed to be computed. Save the computed
457 value. */
458 trad_frame_set_value (info->saved_regs, SIM_LM32_SP_REGNUM, prev_sp);
459
460 return info;
461 }
462
463 static void
464 lm32_frame_this_id (struct frame_info *this_frame, void **this_cache,
465 struct frame_id *this_id)
466 {
467 struct lm32_frame_cache *cache = lm32_frame_cache (this_frame, this_cache);
468
469 /* This marks the outermost frame. */
470 if (cache->base == 0)
471 return;
472
473 (*this_id) = frame_id_build (cache->base, cache->pc);
474 }
475
476 static struct value *
477 lm32_frame_prev_register (struct frame_info *this_frame,
478 void **this_prologue_cache, int regnum)
479 {
480 struct lm32_frame_cache *info;
481
482 info = lm32_frame_cache (this_frame, this_prologue_cache);
483 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
484 }
485
486 static const struct frame_unwind lm32_frame_unwind = {
487 NORMAL_FRAME,
488 default_frame_unwind_stop_reason,
489 lm32_frame_this_id,
490 lm32_frame_prev_register,
491 NULL,
492 default_frame_sniffer
493 };
494
495 static CORE_ADDR
496 lm32_frame_base_address (struct frame_info *this_frame, void **this_cache)
497 {
498 struct lm32_frame_cache *info = lm32_frame_cache (this_frame, this_cache);
499
500 return info->base;
501 }
502
503 static const struct frame_base lm32_frame_base = {
504 &lm32_frame_unwind,
505 lm32_frame_base_address,
506 lm32_frame_base_address,
507 lm32_frame_base_address
508 };
509
510 static CORE_ADDR
511 lm32_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
512 {
513 /* Align to the size of an instruction (so that they can safely be
514 pushed onto the stack. */
515 return sp & ~3;
516 }
517
518 static struct gdbarch *
519 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
520 {
521 struct gdbarch *gdbarch;
522 struct gdbarch_tdep *tdep;
523
524 /* If there is already a candidate, use it. */
525 arches = gdbarch_list_lookup_by_info (arches, &info);
526 if (arches != NULL)
527 return arches->gdbarch;
528
529 /* None found, create a new architecture from the information provided. */
530 tdep = XMALLOC (struct gdbarch_tdep);
531 gdbarch = gdbarch_alloc (&info, tdep);
532
533 /* Type sizes. */
534 set_gdbarch_short_bit (gdbarch, 16);
535 set_gdbarch_int_bit (gdbarch, 32);
536 set_gdbarch_long_bit (gdbarch, 32);
537 set_gdbarch_long_long_bit (gdbarch, 64);
538 set_gdbarch_float_bit (gdbarch, 32);
539 set_gdbarch_double_bit (gdbarch, 64);
540 set_gdbarch_long_double_bit (gdbarch, 64);
541 set_gdbarch_ptr_bit (gdbarch, 32);
542
543 /* Register info. */
544 set_gdbarch_num_regs (gdbarch, SIM_LM32_NUM_REGS);
545 set_gdbarch_sp_regnum (gdbarch, SIM_LM32_SP_REGNUM);
546 set_gdbarch_pc_regnum (gdbarch, SIM_LM32_PC_REGNUM);
547 set_gdbarch_register_name (gdbarch, lm32_register_name);
548 set_gdbarch_register_type (gdbarch, lm32_register_type);
549 set_gdbarch_cannot_store_register (gdbarch, lm32_cannot_store_register);
550
551 /* Frame info. */
552 set_gdbarch_skip_prologue (gdbarch, lm32_skip_prologue);
553 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
554 set_gdbarch_decr_pc_after_break (gdbarch, 0);
555 set_gdbarch_frame_args_skip (gdbarch, 0);
556
557 /* Frame unwinding. */
558 set_gdbarch_frame_align (gdbarch, lm32_frame_align);
559 frame_base_set_default (gdbarch, &lm32_frame_base);
560 set_gdbarch_unwind_pc (gdbarch, lm32_unwind_pc);
561 set_gdbarch_unwind_sp (gdbarch, lm32_unwind_sp);
562 set_gdbarch_dummy_id (gdbarch, lm32_dummy_id);
563 frame_unwind_append_unwinder (gdbarch, &lm32_frame_unwind);
564
565 /* Breakpoints. */
566 set_gdbarch_breakpoint_from_pc (gdbarch, lm32_breakpoint_from_pc);
567 set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
568
569 /* Calling functions in the inferior. */
570 set_gdbarch_push_dummy_call (gdbarch, lm32_push_dummy_call);
571 set_gdbarch_return_value (gdbarch, lm32_return_value);
572
573 /* Instruction disassembler. */
574 set_gdbarch_print_insn (gdbarch, print_insn_lm32);
575
576 lm32_add_reggroups (gdbarch);
577 set_gdbarch_register_reggroup_p (gdbarch, lm32_register_reggroup_p);
578
579 return gdbarch;
580 }
581
582 /* -Wmissing-prototypes */
583 extern initialize_file_ftype _initialize_lm32_tdep;
584
585 void
586 _initialize_lm32_tdep (void)
587 {
588 register_gdbarch_init (bfd_arch_lm32, lm32_gdbarch_init);
589 }
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