| 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 | } |