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c906108c SS |
1 | /* Target dependent code for the Motorola 68000 series. |
2 | Copyright (C) 1990, 1992 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #include "defs.h" | |
21 | #include "frame.h" | |
22 | #include "symtab.h" | |
23 | #include "gdbcore.h" | |
24 | #include "value.h" | |
25 | #include "gdb_string.h" | |
26 | ||
27 | \f | |
28 | /* Push an empty stack frame, to record the current PC, etc. */ | |
29 | ||
30 | void | |
31 | m68k_push_dummy_frame () | |
32 | { | |
33 | register CORE_ADDR sp = read_register (SP_REGNUM); | |
34 | register int regnum; | |
35 | char raw_buffer[12]; | |
36 | ||
37 | sp = push_word (sp, read_register (PC_REGNUM)); | |
38 | sp = push_word (sp, read_register (FP_REGNUM)); | |
39 | write_register (FP_REGNUM, sp); | |
40 | ||
41 | /* Always save the floating-point registers, whether they exist on | |
42 | this target or not. */ | |
43 | for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--) | |
44 | { | |
45 | read_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12); | |
46 | sp = push_bytes (sp, raw_buffer, 12); | |
47 | } | |
48 | ||
49 | for (regnum = FP_REGNUM - 1; regnum >= 0; regnum--) | |
50 | { | |
51 | sp = push_word (sp, read_register (regnum)); | |
52 | } | |
53 | sp = push_word (sp, read_register (PS_REGNUM)); | |
54 | write_register (SP_REGNUM, sp); | |
55 | } | |
56 | ||
57 | /* Discard from the stack the innermost frame, | |
58 | restoring all saved registers. */ | |
59 | ||
60 | void | |
61 | m68k_pop_frame () | |
62 | { | |
63 | register struct frame_info *frame = get_current_frame (); | |
64 | register CORE_ADDR fp; | |
65 | register int regnum; | |
66 | struct frame_saved_regs fsr; | |
67 | char raw_buffer[12]; | |
68 | ||
69 | fp = FRAME_FP (frame); | |
70 | get_frame_saved_regs (frame, &fsr); | |
71 | for (regnum = FP0_REGNUM + 7 ; regnum >= FP0_REGNUM ; regnum--) | |
72 | { | |
73 | if (fsr.regs[regnum]) | |
74 | { | |
75 | read_memory (fsr.regs[regnum], raw_buffer, 12); | |
76 | write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12); | |
77 | } | |
78 | } | |
79 | for (regnum = FP_REGNUM - 1 ; regnum >= 0 ; regnum--) | |
80 | { | |
81 | if (fsr.regs[regnum]) | |
82 | { | |
83 | write_register (regnum, read_memory_integer (fsr.regs[regnum], 4)); | |
84 | } | |
85 | } | |
86 | if (fsr.regs[PS_REGNUM]) | |
87 | { | |
88 | write_register (PS_REGNUM, read_memory_integer (fsr.regs[PS_REGNUM], 4)); | |
89 | } | |
90 | write_register (FP_REGNUM, read_memory_integer (fp, 4)); | |
91 | write_register (PC_REGNUM, read_memory_integer (fp + 4, 4)); | |
92 | write_register (SP_REGNUM, fp + 8); | |
93 | flush_cached_frames (); | |
94 | } | |
95 | ||
96 | \f | |
97 | /* Given an ip value corresponding to the start of a function, | |
98 | return the ip of the first instruction after the function | |
99 | prologue. This is the generic m68k support. Machines which | |
100 | require something different can override the SKIP_PROLOGUE | |
101 | macro to point elsewhere. | |
102 | ||
103 | Some instructions which typically may appear in a function | |
104 | prologue include: | |
105 | ||
106 | A link instruction, word form: | |
107 | ||
108 | link.w %a6,&0 4e56 XXXX | |
109 | ||
110 | A link instruction, long form: | |
111 | ||
112 | link.l %fp,&F%1 480e XXXX XXXX | |
113 | ||
114 | A movm instruction to preserve integer regs: | |
115 | ||
116 | movm.l &M%1,(4,%sp) 48ef XXXX XXXX | |
117 | ||
118 | A fmovm instruction to preserve float regs: | |
119 | ||
120 | fmovm &FPM%1,(FPO%1,%sp) f237 XXXX XXXX XXXX XXXX | |
121 | ||
122 | Some profiling setup code (FIXME, not recognized yet): | |
123 | ||
124 | lea.l (.L3,%pc),%a1 43fb XXXX XXXX XXXX | |
125 | bsr _mcount 61ff XXXX XXXX | |
126 | ||
127 | */ | |
128 | ||
129 | #define P_LINK_L 0x480e | |
130 | #define P_LINK_W 0x4e56 | |
131 | #define P_MOV_L 0x207c | |
132 | #define P_JSR 0x4eb9 | |
133 | #define P_BSR 0x61ff | |
134 | #define P_LEA_L 0x43fb | |
135 | #define P_MOVM_L 0x48ef | |
136 | #define P_FMOVM 0xf237 | |
137 | #define P_TRAP 0x4e40 | |
138 | ||
139 | CORE_ADDR | |
140 | m68k_skip_prologue (ip) | |
141 | CORE_ADDR ip; | |
142 | { | |
143 | register CORE_ADDR limit; | |
144 | struct symtab_and_line sal; | |
145 | register int op; | |
146 | ||
147 | /* Find out if there is a known limit for the extent of the prologue. | |
148 | If so, ensure we don't go past it. If not, assume "infinity". */ | |
149 | ||
150 | sal = find_pc_line (ip, 0); | |
151 | limit = (sal.end) ? sal.end : (CORE_ADDR) ~0; | |
152 | ||
153 | while (ip < limit) | |
154 | { | |
155 | op = read_memory_integer (ip, 2); | |
156 | op &= 0xFFFF; | |
157 | ||
158 | if (op == P_LINK_W) | |
159 | { | |
160 | ip += 4; /* Skip link.w */ | |
161 | } | |
162 | else if (op == 0x4856) | |
163 | ip += 2; /* Skip pea %fp */ | |
164 | else if (op == 0x2c4f) | |
165 | ip += 2; /* Skip move.l %sp, %fp */ | |
166 | else if (op == P_LINK_L) | |
167 | { | |
168 | ip += 6; /* Skip link.l */ | |
169 | } | |
170 | else if (op == P_MOVM_L) | |
171 | { | |
172 | ip += 6; /* Skip movm.l */ | |
173 | } | |
174 | else if (op == P_FMOVM) | |
175 | { | |
176 | ip += 10; /* Skip fmovm */ | |
177 | } | |
178 | else | |
179 | { | |
180 | break; /* Found unknown code, bail out. */ | |
181 | } | |
182 | } | |
183 | return (ip); | |
184 | } | |
185 | ||
186 | void | |
187 | m68k_find_saved_regs (frame_info, saved_regs) | |
188 | struct frame_info *frame_info; | |
189 | struct frame_saved_regs *saved_regs; | |
190 | { | |
191 | register int regnum; | |
192 | register int regmask; | |
193 | register CORE_ADDR next_addr; | |
194 | register CORE_ADDR pc; | |
195 | ||
196 | /* First possible address for a pc in a call dummy for this frame. */ | |
197 | CORE_ADDR possible_call_dummy_start = | |
198 | (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 4 - 8*12; | |
199 | ||
200 | int nextinsn; | |
201 | memset (saved_regs, 0, sizeof (*saved_regs)); | |
202 | if ((frame_info)->pc >= possible_call_dummy_start | |
203 | && (frame_info)->pc <= (frame_info)->frame) | |
204 | { | |
205 | ||
206 | /* It is a call dummy. We could just stop now, since we know | |
207 | what the call dummy saves and where. But this code proceeds | |
208 | to parse the "prologue" which is part of the call dummy. | |
209 | This is needlessly complex and confusing. FIXME. */ | |
210 | ||
211 | next_addr = (frame_info)->frame; | |
212 | pc = possible_call_dummy_start; | |
213 | } | |
214 | else | |
215 | { | |
216 | pc = get_pc_function_start ((frame_info)->pc); | |
217 | ||
218 | if (0x4856 == read_memory_integer (pc, 2) | |
219 | && 0x2c4f == read_memory_integer (pc + 2, 2)) | |
220 | { | |
221 | /* | |
222 | pea %fp | |
223 | move.l %sp, %fp */ | |
224 | ||
225 | pc += 4; | |
226 | next_addr = frame_info->frame; | |
227 | } | |
228 | else if (044016 == read_memory_integer (pc, 2)) | |
229 | /* link.l %fp */ | |
230 | /* Find the address above the saved | |
231 | regs using the amount of storage from the link instruction. */ | |
232 | next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 4), pc+=4; | |
233 | else if (047126 == read_memory_integer (pc, 2)) | |
234 | /* link.w %fp */ | |
235 | /* Find the address above the saved | |
236 | regs using the amount of storage from the link instruction. */ | |
237 | next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 2), pc+=2; | |
238 | else goto lose; | |
239 | ||
240 | /* If have an addal #-n, sp next, adjust next_addr. */ | |
241 | if ((0177777 & read_memory_integer (pc, 2)) == 0157774) | |
242 | next_addr += read_memory_integer (pc += 2, 4), pc += 4; | |
243 | } | |
244 | regmask = read_memory_integer (pc + 2, 2); | |
245 | ||
246 | /* Here can come an fmovem. Check for it. */ | |
247 | nextinsn = 0xffff & read_memory_integer (pc, 2); | |
248 | if (0xf227 == nextinsn | |
249 | && (regmask & 0xff00) == 0xe000) | |
250 | { pc += 4; /* Regmask's low bit is for register fp7, the first pushed */ | |
251 | for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1) | |
252 | if (regmask & 1) | |
253 | saved_regs->regs[regnum] = (next_addr -= 12); | |
254 | regmask = read_memory_integer (pc + 2, 2); } | |
255 | ||
256 | /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */ | |
257 | if (0044327 == read_memory_integer (pc, 2)) | |
258 | { pc += 4; /* Regmask's low bit is for register 0, the first written */ | |
259 | for (regnum = 0; regnum < 16; regnum++, regmask >>= 1) | |
260 | if (regmask & 1) | |
261 | saved_regs->regs[regnum] = (next_addr += 4) - 4; } | |
262 | else if (0044347 == read_memory_integer (pc, 2)) | |
263 | { | |
264 | pc += 4; /* Regmask's low bit is for register 15, the first pushed */ | |
265 | for (regnum = 15; regnum >= 0; regnum--, regmask >>= 1) | |
266 | if (regmask & 1) | |
267 | saved_regs->regs[regnum] = (next_addr -= 4); | |
268 | } | |
269 | else if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2))) | |
270 | { | |
271 | regnum = 0xf & read_memory_integer (pc, 2); pc += 2; | |
272 | saved_regs->regs[regnum] = (next_addr -= 4); | |
273 | /* gcc, at least, may use a pair of movel instructions when saving | |
274 | exactly 2 registers. */ | |
275 | if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2))) | |
276 | { | |
277 | regnum = 0xf & read_memory_integer (pc, 2); | |
278 | pc += 2; | |
279 | saved_regs->regs[regnum] = (next_addr -= 4); | |
280 | } | |
281 | } | |
282 | ||
283 | /* fmovemx to index of sp may follow. */ | |
284 | regmask = read_memory_integer (pc + 2, 2); | |
285 | nextinsn = 0xffff & read_memory_integer (pc, 2); | |
286 | if (0xf236 == nextinsn | |
287 | && (regmask & 0xff00) == 0xf000) | |
288 | { pc += 10; /* Regmask's low bit is for register fp0, the first written */ | |
289 | for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1) | |
290 | if (regmask & 1) | |
291 | saved_regs->regs[regnum] = (next_addr += 12) - 12; | |
292 | regmask = read_memory_integer (pc + 2, 2); } | |
293 | ||
294 | /* clrw -(sp); movw ccr,-(sp) may follow. */ | |
295 | if (0x426742e7 == read_memory_integer (pc, 4)) | |
296 | saved_regs->regs[PS_REGNUM] = (next_addr -= 4); | |
297 | lose: ; | |
298 | saved_regs->regs[SP_REGNUM] = (frame_info)->frame + 8; | |
299 | saved_regs->regs[FP_REGNUM] = (frame_info)->frame; | |
300 | saved_regs->regs[PC_REGNUM] = (frame_info)->frame + 4; | |
301 | #ifdef SIG_SP_FP_OFFSET | |
302 | /* Adjust saved SP_REGNUM for fake _sigtramp frames. */ | |
303 | if (frame_info->signal_handler_caller && frame_info->next) | |
304 | saved_regs->regs[SP_REGNUM] = frame_info->next->frame + SIG_SP_FP_OFFSET; | |
305 | #endif | |
306 | } | |
307 | ||
308 | ||
309 | #ifdef USE_PROC_FS /* Target dependent support for /proc */ | |
310 | ||
311 | #include <sys/procfs.h> | |
312 | ||
313 | /* The /proc interface divides the target machine's register set up into | |
314 | two different sets, the general register set (gregset) and the floating | |
315 | point register set (fpregset). For each set, there is an ioctl to get | |
316 | the current register set and another ioctl to set the current values. | |
317 | ||
318 | The actual structure passed through the ioctl interface is, of course, | |
319 | naturally machine dependent, and is different for each set of registers. | |
320 | For the m68k for example, the general register set is typically defined | |
321 | by: | |
322 | ||
323 | typedef int gregset_t[18]; | |
324 | ||
325 | #define R_D0 0 | |
326 | ... | |
327 | #define R_PS 17 | |
328 | ||
329 | and the floating point set by: | |
330 | ||
331 | typedef struct fpregset { | |
332 | int f_pcr; | |
333 | int f_psr; | |
334 | int f_fpiaddr; | |
335 | int f_fpregs[8][3]; (8 regs, 96 bits each) | |
336 | } fpregset_t; | |
337 | ||
338 | These routines provide the packing and unpacking of gregset_t and | |
339 | fpregset_t formatted data. | |
340 | ||
341 | */ | |
342 | ||
343 | /* Atari SVR4 has R_SR but not R_PS */ | |
344 | ||
345 | #if !defined (R_PS) && defined (R_SR) | |
346 | #define R_PS R_SR | |
347 | #endif | |
348 | ||
349 | /* Given a pointer to a general register set in /proc format (gregset_t *), | |
350 | unpack the register contents and supply them as gdb's idea of the current | |
351 | register values. */ | |
352 | ||
353 | void | |
354 | supply_gregset (gregsetp) | |
355 | gregset_t *gregsetp; | |
356 | { | |
357 | register int regi; | |
358 | register greg_t *regp = (greg_t *) gregsetp; | |
359 | ||
360 | for (regi = 0 ; regi < R_PC ; regi++) | |
361 | { | |
362 | supply_register (regi, (char *) (regp + regi)); | |
363 | } | |
364 | supply_register (PS_REGNUM, (char *) (regp + R_PS)); | |
365 | supply_register (PC_REGNUM, (char *) (regp + R_PC)); | |
366 | } | |
367 | ||
368 | void | |
369 | fill_gregset (gregsetp, regno) | |
370 | gregset_t *gregsetp; | |
371 | int regno; | |
372 | { | |
373 | register int regi; | |
374 | register greg_t *regp = (greg_t *) gregsetp; | |
375 | extern char registers[]; | |
376 | ||
377 | for (regi = 0 ; regi < R_PC ; regi++) | |
378 | { | |
379 | if ((regno == -1) || (regno == regi)) | |
380 | { | |
381 | *(regp + regi) = *(int *) ®isters[REGISTER_BYTE (regi)]; | |
382 | } | |
383 | } | |
384 | if ((regno == -1) || (regno == PS_REGNUM)) | |
385 | { | |
386 | *(regp + R_PS) = *(int *) ®isters[REGISTER_BYTE (PS_REGNUM)]; | |
387 | } | |
388 | if ((regno == -1) || (regno == PC_REGNUM)) | |
389 | { | |
390 | *(regp + R_PC) = *(int *) ®isters[REGISTER_BYTE (PC_REGNUM)]; | |
391 | } | |
392 | } | |
393 | ||
394 | #if defined (FP0_REGNUM) | |
395 | ||
396 | /* Given a pointer to a floating point register set in /proc format | |
397 | (fpregset_t *), unpack the register contents and supply them as gdb's | |
398 | idea of the current floating point register values. */ | |
399 | ||
400 | void | |
401 | supply_fpregset (fpregsetp) | |
402 | fpregset_t *fpregsetp; | |
403 | { | |
404 | register int regi; | |
405 | char *from; | |
406 | ||
407 | for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++) | |
408 | { | |
409 | from = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]); | |
410 | supply_register (regi, from); | |
411 | } | |
412 | supply_register (FPC_REGNUM, (char *) &(fpregsetp -> f_pcr)); | |
413 | supply_register (FPS_REGNUM, (char *) &(fpregsetp -> f_psr)); | |
414 | supply_register (FPI_REGNUM, (char *) &(fpregsetp -> f_fpiaddr)); | |
415 | } | |
416 | ||
417 | /* Given a pointer to a floating point register set in /proc format | |
418 | (fpregset_t *), update the register specified by REGNO from gdb's idea | |
419 | of the current floating point register set. If REGNO is -1, update | |
420 | them all. */ | |
421 | ||
422 | void | |
423 | fill_fpregset (fpregsetp, regno) | |
424 | fpregset_t *fpregsetp; | |
425 | int regno; | |
426 | { | |
427 | int regi; | |
428 | char *to; | |
429 | char *from; | |
430 | extern char registers[]; | |
431 | ||
432 | for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++) | |
433 | { | |
434 | if ((regno == -1) || (regno == regi)) | |
435 | { | |
436 | from = (char *) ®isters[REGISTER_BYTE (regi)]; | |
437 | to = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]); | |
438 | memcpy (to, from, REGISTER_RAW_SIZE (regi)); | |
439 | } | |
440 | } | |
441 | if ((regno == -1) || (regno == FPC_REGNUM)) | |
442 | { | |
443 | fpregsetp -> f_pcr = *(int *) ®isters[REGISTER_BYTE (FPC_REGNUM)]; | |
444 | } | |
445 | if ((regno == -1) || (regno == FPS_REGNUM)) | |
446 | { | |
447 | fpregsetp -> f_psr = *(int *) ®isters[REGISTER_BYTE (FPS_REGNUM)]; | |
448 | } | |
449 | if ((regno == -1) || (regno == FPI_REGNUM)) | |
450 | { | |
451 | fpregsetp -> f_fpiaddr = *(int *) ®isters[REGISTER_BYTE (FPI_REGNUM)]; | |
452 | } | |
453 | } | |
454 | ||
455 | #endif /* defined (FP0_REGNUM) */ | |
456 | ||
457 | #endif /* USE_PROC_FS */ | |
458 | ||
459 | #ifdef GET_LONGJMP_TARGET | |
460 | /* Figure out where the longjmp will land. Slurp the args out of the stack. | |
461 | We expect the first arg to be a pointer to the jmp_buf structure from which | |
462 | we extract the pc (JB_PC) that we will land at. The pc is copied into PC. | |
463 | This routine returns true on success. */ | |
464 | ||
465 | int | |
466 | get_longjmp_target(pc) | |
467 | CORE_ADDR *pc; | |
468 | { | |
469 | char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT]; | |
470 | CORE_ADDR sp, jb_addr; | |
471 | ||
472 | sp = read_register(SP_REGNUM); | |
473 | ||
474 | if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */ | |
475 | buf, | |
476 | TARGET_PTR_BIT / TARGET_CHAR_BIT)) | |
477 | return 0; | |
478 | ||
479 | jb_addr = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); | |
480 | ||
481 | if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf, | |
482 | TARGET_PTR_BIT / TARGET_CHAR_BIT)) | |
483 | return 0; | |
484 | ||
485 | *pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); | |
486 | ||
487 | return 1; | |
488 | } | |
489 | #endif /* GET_LONGJMP_TARGET */ | |
490 | ||
491 | /* Immediately after a function call, return the saved pc before the frame | |
492 | is setup. For sun3's, we check for the common case of being inside of a | |
493 | system call, and if so, we know that Sun pushes the call # on the stack | |
494 | prior to doing the trap. */ | |
495 | ||
496 | CORE_ADDR | |
497 | m68k_saved_pc_after_call(frame) | |
498 | struct frame_info *frame; | |
499 | { | |
500 | #ifdef SYSCALL_TRAP | |
501 | int op; | |
502 | ||
503 | op = read_memory_integer (frame->pc - SYSCALL_TRAP_OFFSET, 2); | |
504 | ||
505 | if (op == SYSCALL_TRAP) | |
506 | return read_memory_integer (read_register (SP_REGNUM) + 4, 4); | |
507 | else | |
508 | #endif /* SYSCALL_TRAP */ | |
509 | return read_memory_integer (read_register (SP_REGNUM), 4); | |
510 | } | |
511 | ||
512 | void | |
513 | _initialize_m68k_tdep () | |
514 | { | |
515 | tm_print_insn = print_insn_m68k; | |
516 | } |