1/* Target-dependent code for the Motorola 68000 series. 2 3 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1999, 2000, 4 2001, 2002, 2003, 2004 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 2 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, write to the Free Software 20 Foundation, Inc., 59 Temple Place - Suite 330, 21 Boston, MA 02111-1307, USA. */ 22 23#include "defs.h" 24#include "dwarf2-frame.h" 25#include "frame.h" 26#include "frame-base.h" 27#include "frame-unwind.h" 28#include "floatformat.h" 29#include "symtab.h" 30#include "gdbcore.h" 31#include "value.h" 32#include "gdb_string.h" 33#include "gdb_assert.h" 34#include "inferior.h" 35#include "regcache.h" 36#include "arch-utils.h" 37#include "osabi.h" 38#include "dis-asm.h" 39 40#include "m68k-tdep.h" 41 42 43#define P_LINKL_FP 0x480e 44#define P_LINKW_FP 0x4e56 45#define P_PEA_FP 0x4856 46#define P_MOVEAL_SP_FP 0x2c4f 47#define P_ADDAW_SP 0xdefc 48#define P_ADDAL_SP 0xdffc 49#define P_SUBQW_SP 0x514f 50#define P_SUBQL_SP 0x518f 51#define P_LEA_SP_SP 0x4fef 52#define P_LEA_PC_A5 0x4bfb0170 53#define P_FMOVEMX_SP 0xf227 54#define P_MOVEL_SP 0x2f00 55#define P_MOVEML_SP 0x48e7 56 57 58#define REGISTER_BYTES_FP (16*4 + 8 + 8*12 + 3*4) 59#define REGISTER_BYTES_NOFP (16*4 + 8) 60 61/* Offset from SP to first arg on stack at first instruction of a function */ 62#define SP_ARG0 (1 * 4) 63 64#if !defined (BPT_VECTOR) 65#define BPT_VECTOR 0xf 66#endif 67 68static const unsigned char * 69m68k_local_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr) 70{ 71 static unsigned char break_insn[] = {0x4e, (0x40 | BPT_VECTOR)}; 72 *lenptr = sizeof (break_insn); 73 return break_insn; 74} 75 76 77static int 78m68k_register_bytes_ok (long numbytes) 79{ 80 return ((numbytes == REGISTER_BYTES_FP) 81 || (numbytes == REGISTER_BYTES_NOFP)); 82} 83 84/* Return the GDB type object for the "standard" data type of data in 85 register N. This should be int for D0-D7, SR, FPCONTROL and 86 FPSTATUS, long double for FP0-FP7, and void pointer for all others 87 (A0-A7, PC, FPIADDR). Note, for registers which contain 88 addresses return pointer to void, not pointer to char, because we 89 don't want to attempt to print the string after printing the 90 address. */ 91 92static struct type * 93m68k_register_type (struct gdbarch *gdbarch, int regnum) 94{ 95 if (regnum >= FP0_REGNUM && regnum <= FP0_REGNUM + 7) 96 return builtin_type_m68881_ext; 97 98 if (regnum == M68K_FPI_REGNUM || regnum == PC_REGNUM) 99 return builtin_type_void_func_ptr; 100 101 if (regnum == M68K_FPC_REGNUM || regnum == M68K_FPS_REGNUM 102 || regnum == PS_REGNUM) 103 return builtin_type_int32; 104 105 if (regnum >= M68K_A0_REGNUM && regnum <= M68K_A0_REGNUM + 7) 106 return builtin_type_void_data_ptr; 107 108 return builtin_type_int32; 109} 110 111/* Function: m68k_register_name 112 Returns the name of the standard m68k register regnum. */ 113 114static const char * 115m68k_register_name (int regnum) 116{ 117 static char *register_names[] = { 118 "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", 119 "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp", 120 "ps", "pc", 121 "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7", 122 "fpcontrol", "fpstatus", "fpiaddr", "fpcode", "fpflags" 123 }; 124 125 if (regnum < 0 || 126 regnum >= sizeof (register_names) / sizeof (register_names[0])) 127 internal_error (__FILE__, __LINE__, 128 "m68k_register_name: illegal register number %d", regnum); 129 else 130 return register_names[regnum]; 131} 132 133/* Return nonzero if a value of type TYPE stored in register REGNUM 134 needs any special handling. */ 135 136static int 137m68k_convert_register_p (int regnum, struct type *type) 138{ 139 return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7); 140} 141 142/* Read a value of type TYPE from register REGNUM in frame FRAME, and 143 return its contents in TO. */ 144 145static void 146m68k_register_to_value (struct frame_info *frame, int regnum, 147 struct type *type, void *to) 148{ 149 char from[M68K_MAX_REGISTER_SIZE]; 150 151 /* We only support floating-point values. */ 152 if (TYPE_CODE (type) != TYPE_CODE_FLT) 153 { 154 warning ("Cannot convert floating-point register value " 155 "to non-floating-point type."); 156 return; 157 } 158 159 /* Convert to TYPE. This should be a no-op if TYPE is equivalent to 160 the extended floating-point format used by the FPU. */ 161 get_frame_register (frame, regnum, from); 162 convert_typed_floating (from, builtin_type_m68881_ext, to, type); 163} 164 165/* Write the contents FROM of a value of type TYPE into register 166 REGNUM in frame FRAME. */ 167 168static void 169m68k_value_to_register (struct frame_info *frame, int regnum, 170 struct type *type, const void *from) 171{ 172 char to[M68K_MAX_REGISTER_SIZE]; 173 174 /* We only support floating-point values. */ 175 if (TYPE_CODE (type) != TYPE_CODE_FLT) 176 { 177 warning ("Cannot convert non-floating-point type " 178 "to floating-point register value."); 179 return; 180 } 181 182 /* Convert from TYPE. This should be a no-op if TYPE is equivalent 183 to the extended floating-point format used by the FPU. */ 184 convert_typed_floating (from, type, to, builtin_type_m68881_ext); 185 put_frame_register (frame, regnum, to); 186} 187 188 189/* There is a fair number of calling conventions that are in somewhat 190 wide use. The 68000/08/10 don't support an FPU, not even as a 191 coprocessor. All function return values are stored in %d0/%d1. 192 Structures are returned in a static buffer, a pointer to which is 193 returned in %d0. This means that functions returning a structure 194 are not re-entrant. To avoid this problem some systems use a 195 convention where the caller passes a pointer to a buffer in %a1 196 where the return values is to be stored. This convention is the 197 default, and is implemented in the function m68k_return_value. 198 199 The 68020/030/040/060 do support an FPU, either as a coprocessor 200 (68881/2) or built-in (68040/68060). That's why System V release 4 201 (SVR4) instroduces a new calling convention specified by the SVR4 202 psABI. Integer values are returned in %d0/%d1, pointer return 203 values in %a0 and floating values in %fp0. When calling functions 204 returning a structure the caller should pass a pointer to a buffer 205 for the return value in %a0. This convention is implemented in the 206 function m68k_svr4_return_value, and by appropriately setting the 207 struct_value_regnum member of `struct gdbarch_tdep'. 208 209 GNU/Linux returns values in the same way as SVR4 does, but uses %a1 210 for passing the structure return value buffer. 211 212 GCC can also generate code where small structures are returned in 213 %d0/%d1 instead of in memory by using -freg-struct-return. This is 214 the default on NetBSD a.out, OpenBSD and GNU/Linux and several 215 embedded systems. This convention is implemented by setting the 216 struct_return member of `struct gdbarch_tdep' to reg_struct_return. */ 217 218/* Read a function return value of TYPE from REGCACHE, and copy that 219 into VALBUF. */ 220 221static void 222m68k_extract_return_value (struct type *type, struct regcache *regcache, 223 void *valbuf) 224{ 225 int len = TYPE_LENGTH (type); 226 char buf[M68K_MAX_REGISTER_SIZE]; 227 228 if (len <= 4) 229 { 230 regcache_raw_read (regcache, M68K_D0_REGNUM, buf); 231 memcpy (valbuf, buf + (4 - len), len); 232 } 233 else if (len <= 8) 234 { 235 regcache_raw_read (regcache, M68K_D0_REGNUM, buf); 236 memcpy (valbuf, buf + (8 - len), len - 4); 237 regcache_raw_read (regcache, M68K_D1_REGNUM, 238 (char *) valbuf + (len - 4)); 239 } 240 else 241 internal_error (__FILE__, __LINE__, 242 "Cannot extract return value of %d bytes long.", len); 243} 244 245static void 246m68k_svr4_extract_return_value (struct type *type, struct regcache *regcache, 247 void *valbuf) 248{ 249 int len = TYPE_LENGTH (type); 250 char buf[M68K_MAX_REGISTER_SIZE]; 251 252 if (TYPE_CODE (type) == TYPE_CODE_FLT) 253 { 254 regcache_raw_read (regcache, M68K_FP0_REGNUM, buf); 255 convert_typed_floating (buf, builtin_type_m68881_ext, valbuf, type); 256 } 257 else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4) 258 regcache_raw_read (regcache, M68K_A0_REGNUM, valbuf); 259 else 260 m68k_extract_return_value (type, regcache, valbuf); 261} 262 263/* Write a function return value of TYPE from VALBUF into REGCACHE. */ 264 265static void 266m68k_store_return_value (struct type *type, struct regcache *regcache, 267 const void *valbuf) 268{ 269 int len = TYPE_LENGTH (type); 270 271 if (len <= 4) 272 regcache_raw_write_part (regcache, M68K_D0_REGNUM, 4 - len, len, valbuf); 273 else if (len <= 8) 274 { 275 regcache_raw_write_part (regcache, M68K_D0_REGNUM, 8 - len, 276 len - 4, valbuf); 277 regcache_raw_write (regcache, M68K_D1_REGNUM, 278 (char *) valbuf + (len - 4)); 279 } 280 else 281 internal_error (__FILE__, __LINE__, 282 "Cannot store return value of %d bytes long.", len); 283} 284 285static void 286m68k_svr4_store_return_value (struct type *type, struct regcache *regcache, 287 const void *valbuf) 288{ 289 int len = TYPE_LENGTH (type); 290 291 if (TYPE_CODE (type) == TYPE_CODE_FLT) 292 { 293 char buf[M68K_MAX_REGISTER_SIZE]; 294 convert_typed_floating (valbuf, type, buf, builtin_type_m68881_ext); 295 regcache_raw_write (regcache, M68K_FP0_REGNUM, buf); 296 } 297 else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4) 298 { 299 regcache_raw_write (regcache, M68K_A0_REGNUM, valbuf); 300 regcache_raw_write (regcache, M68K_D0_REGNUM, valbuf); 301 } 302 else 303 m68k_store_return_value (type, regcache, valbuf); 304} 305 306/* Return non-zero if TYPE, which is assumed to be a structure or 307 union type, should be returned in registers for architecture 308 GDBARCH. */ 309 310static int 311m68k_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type) 312{ 313 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 314 enum type_code code = TYPE_CODE (type); 315 int len = TYPE_LENGTH (type); 316 317 gdb_assert (code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION); 318 319 if (tdep->struct_return == pcc_struct_return) 320 return 0; 321 322 return (len == 1 || len == 2 || len == 4 || len == 8); 323} 324 325/* Determine, for architecture GDBARCH, how a return value of TYPE 326 should be returned. If it is supposed to be returned in registers, 327 and READBUF is non-zero, read the appropriate value from REGCACHE, 328 and copy it into READBUF. If WRITEBUF is non-zero, write the value 329 from WRITEBUF into REGCACHE. */ 330 331static enum return_value_convention 332m68k_return_value (struct gdbarch *gdbarch, struct type *type, 333 struct regcache *regcache, void *readbuf, 334 const void *writebuf) 335{ 336 enum type_code code = TYPE_CODE (type); 337 338 if ((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION) 339 && !m68k_reg_struct_return_p (gdbarch, type)) 340 return RETURN_VALUE_STRUCT_CONVENTION; 341 342 /* GCC returns a `long double' in memory. */ 343 if (code == TYPE_CODE_FLT && TYPE_LENGTH (type) == 12) 344 return RETURN_VALUE_STRUCT_CONVENTION; 345 346 if (readbuf) 347 m68k_extract_return_value (type, regcache, readbuf); 348 if (writebuf) 349 m68k_store_return_value (type, regcache, writebuf); 350 351 return RETURN_VALUE_REGISTER_CONVENTION; 352} 353 354static enum return_value_convention 355m68k_svr4_return_value (struct gdbarch *gdbarch, struct type *type, 356 struct regcache *regcache, void *readbuf, 357 const void *writebuf) 358{ 359 enum type_code code = TYPE_CODE (type); 360 361 if ((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION) 362 && !m68k_reg_struct_return_p (gdbarch, type)) 363 { 364 /* The System V ABI says that: 365 366 "A function returning a structure or union also sets %a0 to 367 the value it finds in %a0. Thus when the caller receives 368 control again, the address of the returned object resides in 369 register %a0." 370 371 So the ABI guarantees that we can always find the return 372 value just after the function has returned. */ 373 374 if (readbuf) 375 { 376 ULONGEST addr; 377 378 regcache_raw_read_unsigned (regcache, M68K_A0_REGNUM, &addr); 379 read_memory (addr, readbuf, TYPE_LENGTH (type)); 380 } 381 382 return RETURN_VALUE_ABI_RETURNS_ADDRESS; 383 } 384 385 /* This special case is for structures consisting of a single 386 `float' or `double' member. These structures are returned in 387 %fp0. For these structures, we call ourselves recursively, 388 changing TYPE into the type of the first member of the structure. 389 Since that should work for all structures that have only one 390 member, we don't bother to check the member's type here. */ 391 if (code == TYPE_CODE_STRUCT && TYPE_NFIELDS (type) == 1) 392 { 393 type = check_typedef (TYPE_FIELD_TYPE (type, 0)); 394 return m68k_svr4_return_value (gdbarch, type, regcache, 395 readbuf, writebuf); 396 } 397 398 if (readbuf) 399 m68k_svr4_extract_return_value (type, regcache, readbuf); 400 if (writebuf) 401 m68k_svr4_store_return_value (type, regcache, writebuf); 402 403 return RETURN_VALUE_REGISTER_CONVENTION; 404} 405 406 407static CORE_ADDR 408m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function, 409 struct regcache *regcache, CORE_ADDR bp_addr, int nargs, 410 struct value **args, CORE_ADDR sp, int struct_return, 411 CORE_ADDR struct_addr) 412{ 413 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 414 char buf[4]; 415 int i; 416 417 /* Push arguments in reverse order. */ 418 for (i = nargs - 1; i >= 0; i--) 419 { 420 struct type *value_type = VALUE_ENCLOSING_TYPE (args[i]); 421 int len = TYPE_LENGTH (value_type); 422 int container_len = (len + 3) & ~3; 423 int offset; 424 425 /* Non-scalars bigger than 4 bytes are left aligned, others are 426 right aligned. */ 427 if ((TYPE_CODE (value_type) == TYPE_CODE_STRUCT 428 || TYPE_CODE (value_type) == TYPE_CODE_UNION 429 || TYPE_CODE (value_type) == TYPE_CODE_ARRAY) 430 && len > 4) 431 offset = 0; 432 else 433 offset = container_len - len; 434 sp -= container_len; 435 write_memory (sp + offset, VALUE_CONTENTS_ALL (args[i]), len); 436 } 437 438 /* Store struct value address. */ 439 if (struct_return) 440 { 441 store_unsigned_integer (buf, 4, struct_addr); 442 regcache_cooked_write (regcache, tdep->struct_value_regnum, buf); 443 } 444 445 /* Store return address. */ 446 sp -= 4; 447 store_unsigned_integer (buf, 4, bp_addr); 448 write_memory (sp, buf, 4); 449 450 /* Finally, update the stack pointer... */ 451 store_unsigned_integer (buf, 4, sp); 452 regcache_cooked_write (regcache, M68K_SP_REGNUM, buf); 453 454 /* ...and fake a frame pointer. */ 455 regcache_cooked_write (regcache, M68K_FP_REGNUM, buf); 456 457 /* DWARF2/GCC uses the stack address *before* the function call as a 458 frame's CFA. */ 459 return sp + 8; 460} 461 462struct m68k_frame_cache 463{ 464 /* Base address. */ 465 CORE_ADDR base; 466 CORE_ADDR sp_offset; 467 CORE_ADDR pc; 468 469 /* Saved registers. */ 470 CORE_ADDR saved_regs[M68K_NUM_REGS]; 471 CORE_ADDR saved_sp; 472 473 /* Stack space reserved for local variables. */ 474 long locals; 475}; 476 477/* Allocate and initialize a frame cache. */ 478 479static struct m68k_frame_cache * 480m68k_alloc_frame_cache (void) 481{ 482 struct m68k_frame_cache *cache; 483 int i; 484 485 cache = FRAME_OBSTACK_ZALLOC (struct m68k_frame_cache); 486 487 /* Base address. */ 488 cache->base = 0; 489 cache->sp_offset = -4; 490 cache->pc = 0; 491 492 /* Saved registers. We initialize these to -1 since zero is a valid 493 offset (that's where %fp is supposed to be stored). */ 494 for (i = 0; i < M68K_NUM_REGS; i++) 495 cache->saved_regs[i] = -1; 496 497 /* Frameless until proven otherwise. */ 498 cache->locals = -1; 499 500 return cache; 501} 502 503/* Check whether PC points at a code that sets up a new stack frame. 504 If so, it updates CACHE and returns the address of the first 505 instruction after the sequence that sets removes the "hidden" 506 argument from the stack or CURRENT_PC, whichever is smaller. 507 Otherwise, return PC. */ 508 509static CORE_ADDR 510m68k_analyze_frame_setup (CORE_ADDR pc, CORE_ADDR current_pc, 511 struct m68k_frame_cache *cache) 512{ 513 int op; 514 515 if (pc >= current_pc) 516 return current_pc; 517 518 op = read_memory_unsigned_integer (pc, 2); 519 520 if (op == P_LINKW_FP || op == P_LINKL_FP || op == P_PEA_FP) 521 { 522 cache->saved_regs[M68K_FP_REGNUM] = 0; 523 cache->sp_offset += 4; 524 if (op == P_LINKW_FP) 525 { 526 /* link.w %fp, #-N */ 527 /* link.w %fp, #0; adda.l #-N, %sp */ 528 cache->locals = -read_memory_integer (pc + 2, 2); 529 530 if (pc + 4 < current_pc && cache->locals == 0) 531 { 532 op = read_memory_unsigned_integer (pc + 4, 2); 533 if (op == P_ADDAL_SP) 534 { 535 cache->locals = read_memory_integer (pc + 6, 4); 536 return pc + 10; 537 } 538 } 539 540 return pc + 4; 541 } 542 else if (op == P_LINKL_FP) 543 { 544 /* link.l %fp, #-N */ 545 cache->locals = -read_memory_integer (pc + 2, 4); 546 return pc + 6; 547 } 548 else 549 { 550 /* pea (%fp); movea.l %sp, %fp */ 551 cache->locals = 0; 552 553 if (pc + 2 < current_pc) 554 { 555 op = read_memory_unsigned_integer (pc + 2, 2); 556 557 if (op == P_MOVEAL_SP_FP) 558 { 559 /* move.l %sp, %fp */ 560 return pc + 4; 561 } 562 } 563 564 return pc + 2; 565 } 566 } 567 else if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP) 568 { 569 /* subq.[wl] #N,%sp */ 570 /* subq.[wl] #8,%sp; subq.[wl] #N,%sp */ 571 cache->locals = (op & 07000) == 0 ? 8 : (op & 07000) >> 9; 572 if (pc + 2 < current_pc) 573 { 574 op = read_memory_unsigned_integer (pc + 2, 2); 575 if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP) 576 { 577 cache->locals += (op & 07000) == 0 ? 8 : (op & 07000) >> 9; 578 return pc + 4; 579 } 580 } 581 return pc + 2; 582 } 583 else if (op == P_ADDAW_SP || op == P_LEA_SP_SP) 584 { 585 /* adda.w #-N,%sp */ 586 /* lea (-N,%sp),%sp */ 587 cache->locals = -read_memory_integer (pc + 2, 2); 588 return pc + 4; 589 } 590 else if (op == P_ADDAL_SP) 591 { 592 /* adda.l #-N,%sp */ 593 cache->locals = -read_memory_integer (pc + 2, 4); 594 return pc + 6; 595 } 596 597 return pc; 598} 599 600/* Check whether PC points at code that saves registers on the stack. 601 If so, it updates CACHE and returns the address of the first 602 instruction after the register saves or CURRENT_PC, whichever is 603 smaller. Otherwise, return PC. */ 604 605static CORE_ADDR 606m68k_analyze_register_saves (CORE_ADDR pc, CORE_ADDR current_pc, 607 struct m68k_frame_cache *cache) 608{ 609 if (cache->locals >= 0) 610 { 611 CORE_ADDR offset; 612 int op; 613 int i, mask, regno; 614 615 offset = -4 - cache->locals; 616 while (pc < current_pc) 617 { 618 op = read_memory_unsigned_integer (pc, 2); 619 if (op == P_FMOVEMX_SP) 620 { 621 /* fmovem.x REGS,-(%sp) */ 622 op = read_memory_unsigned_integer (pc + 2, 2); 623 if ((op & 0xff00) == 0xe000) 624 { 625 mask = op & 0xff; 626 for (i = 0; i < 16; i++, mask >>= 1) 627 { 628 if (mask & 1) 629 { 630 cache->saved_regs[i + M68K_FP0_REGNUM] = offset; 631 offset -= 12; 632 } 633 } 634 pc += 4; 635 } 636 else 637 break; 638 } 639 else if ((op & 0170677) == P_MOVEL_SP) 640 { 641 /* move.l %R,-(%sp) */ 642 regno = ((op & 07000) >> 9) | ((op & 0100) >> 3); 643 cache->saved_regs[regno] = offset; 644 offset -= 4; 645 pc += 2; 646 } 647 else if (op == P_MOVEML_SP) 648 { 649 /* movem.l REGS,-(%sp) */ 650 mask = read_memory_unsigned_integer (pc + 2, 2); 651 for (i = 0; i < 16; i++, mask >>= 1) 652 { 653 if (mask & 1) 654 { 655 cache->saved_regs[15 - i] = offset; 656 offset -= 4; 657 } 658 } 659 pc += 4; 660 } 661 else 662 break; 663 } 664 } 665 666 return pc; 667} 668 669 670/* Do a full analysis of the prologue at PC and update CACHE 671 accordingly. Bail out early if CURRENT_PC is reached. Return the 672 address where the analysis stopped. 673 674 We handle all cases that can be generated by gcc. 675 676 For allocating a stack frame: 677 678 link.w %a6,#-N 679 link.l %a6,#-N 680 pea (%fp); move.l %sp,%fp 681 link.w %a6,#0; add.l #-N,%sp 682 subq.l #N,%sp 683 subq.w #N,%sp 684 subq.w #8,%sp; subq.w #N-8,%sp 685 add.w #-N,%sp 686 lea (-N,%sp),%sp 687 add.l #-N,%sp 688 689 For saving registers: 690 691 fmovem.x REGS,-(%sp) 692 move.l R1,-(%sp) 693 move.l R1,-(%sp); move.l R2,-(%sp) 694 movem.l REGS,-(%sp) 695 696 For setting up the PIC register: 697 698 lea (%pc,N),%a5 699 700 */ 701 702static CORE_ADDR 703m68k_analyze_prologue (CORE_ADDR pc, CORE_ADDR current_pc, 704 struct m68k_frame_cache *cache) 705{ 706 unsigned int op; 707 708 pc = m68k_analyze_frame_setup (pc, current_pc, cache); 709 pc = m68k_analyze_register_saves (pc, current_pc, cache); 710 if (pc >= current_pc) 711 return current_pc; 712 713 /* Check for GOT setup. */ 714 op = read_memory_unsigned_integer (pc, 4); 715 if (op == P_LEA_PC_A5) 716 { 717 /* lea (%pc,N),%a5 */ 718 return pc + 6; 719 } 720 721 return pc; 722} 723 724/* Return PC of first real instruction. */ 725 726static CORE_ADDR 727m68k_skip_prologue (CORE_ADDR start_pc) 728{ 729 struct m68k_frame_cache cache; 730 CORE_ADDR pc; 731 int op; 732 733 cache.locals = -1; 734 pc = m68k_analyze_prologue (start_pc, (CORE_ADDR) -1, &cache); 735 if (cache.locals < 0) 736 return start_pc; 737 return pc; 738} 739 740static CORE_ADDR 741m68k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) 742{ 743 char buf[8]; 744 745 frame_unwind_register (next_frame, PC_REGNUM, buf); 746 return extract_typed_address (buf, builtin_type_void_func_ptr); 747} 748 749/* Normal frames. */ 750 751static struct m68k_frame_cache * 752m68k_frame_cache (struct frame_info *next_frame, void **this_cache) 753{ 754 struct m68k_frame_cache *cache; 755 char buf[4]; 756 int i; 757 758 if (*this_cache) 759 return *this_cache; 760 761 cache = m68k_alloc_frame_cache (); 762 *this_cache = cache; 763 764 /* In principle, for normal frames, %fp holds the frame pointer, 765 which holds the base address for the current stack frame. 766 However, for functions that don't need it, the frame pointer is 767 optional. For these "frameless" functions the frame pointer is 768 actually the frame pointer of the calling frame. Signal 769 trampolines are just a special case of a "frameless" function. 770 They (usually) share their frame pointer with the frame that was 771 in progress when the signal occurred. */ 772 773 frame_unwind_register (next_frame, M68K_FP_REGNUM, buf); 774 cache->base = extract_unsigned_integer (buf, 4); 775 if (cache->base == 0) 776 return cache; 777 778 /* For normal frames, %pc is stored at 4(%fp). */ 779 cache->saved_regs[M68K_PC_REGNUM] = 4; 780 781 cache->pc = frame_func_unwind (next_frame); 782 if (cache->pc != 0) 783 m68k_analyze_prologue (cache->pc, frame_pc_unwind (next_frame), cache); 784 785 if (cache->locals < 0) 786 { 787 /* We didn't find a valid frame, which means that CACHE->base 788 currently holds the frame pointer for our calling frame. If 789 we're at the start of a function, or somewhere half-way its 790 prologue, the function's frame probably hasn't been fully 791 setup yet. Try to reconstruct the base address for the stack 792 frame by looking at the stack pointer. For truly "frameless" 793 functions this might work too. */ 794 795 frame_unwind_register (next_frame, M68K_SP_REGNUM, buf); 796 cache->base = extract_unsigned_integer (buf, 4) + cache->sp_offset; 797 } 798 799 /* Now that we have the base address for the stack frame we can 800 calculate the value of %sp in the calling frame. */ 801 cache->saved_sp = cache->base + 8; 802 803 /* Adjust all the saved registers such that they contain addresses 804 instead of offsets. */ 805 for (i = 0; i < M68K_NUM_REGS; i++) 806 if (cache->saved_regs[i] != -1) 807 cache->saved_regs[i] += cache->base; 808 809 return cache; 810} 811 812static void 813m68k_frame_this_id (struct frame_info *next_frame, void **this_cache, 814 struct frame_id *this_id) 815{ 816 struct m68k_frame_cache *cache = m68k_frame_cache (next_frame, this_cache); 817 818 /* This marks the outermost frame. */ 819 if (cache->base == 0) 820 return; 821 822 /* See the end of m68k_push_dummy_call. */ 823 *this_id = frame_id_build (cache->base + 8, cache->pc); 824} 825 826static void 827m68k_frame_prev_register (struct frame_info *next_frame, void **this_cache, 828 int regnum, int *optimizedp, 829 enum lval_type *lvalp, CORE_ADDR *addrp, 830 int *realnump, void *valuep) 831{ 832 struct m68k_frame_cache *cache = m68k_frame_cache (next_frame, this_cache); 833 834 gdb_assert (regnum >= 0); 835 836 if (regnum == M68K_SP_REGNUM && cache->saved_sp) 837 { 838 *optimizedp = 0; 839 *lvalp = not_lval; 840 *addrp = 0; 841 *realnump = -1; 842 if (valuep) 843 { 844 /* Store the value. */ 845 store_unsigned_integer (valuep, 4, cache->saved_sp); 846 } 847 return; 848 } 849 850 if (regnum < M68K_NUM_REGS && cache->saved_regs[regnum] != -1) 851 { 852 *optimizedp = 0; 853 *lvalp = lval_memory; 854 *addrp = cache->saved_regs[regnum]; 855 *realnump = -1; 856 if (valuep) 857 { 858 /* Read the value in from memory. */ 859 read_memory (*addrp, valuep, 860 register_size (current_gdbarch, regnum)); 861 } 862 return; 863 } 864 865 frame_register_unwind (next_frame, regnum, 866 optimizedp, lvalp, addrp, realnump, valuep); 867} 868 869static const struct frame_unwind m68k_frame_unwind = 870{ 871 NORMAL_FRAME, 872 m68k_frame_this_id, 873 m68k_frame_prev_register 874}; 875 876static const struct frame_unwind * 877m68k_frame_sniffer (struct frame_info *next_frame) 878{ 879 return &m68k_frame_unwind; 880} 881 882static CORE_ADDR 883m68k_frame_base_address (struct frame_info *next_frame, void **this_cache) 884{ 885 struct m68k_frame_cache *cache = m68k_frame_cache (next_frame, this_cache); 886 887 return cache->base; 888} 889 890static const struct frame_base m68k_frame_base = 891{ 892 &m68k_frame_unwind, 893 m68k_frame_base_address, 894 m68k_frame_base_address, 895 m68k_frame_base_address 896}; 897 898static struct frame_id 899m68k_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame) 900{ 901 char buf[4]; 902 CORE_ADDR fp; 903 904 frame_unwind_register (next_frame, M68K_FP_REGNUM, buf); 905 fp = extract_unsigned_integer (buf, 4); 906 907 /* See the end of m68k_push_dummy_call. */ 908 return frame_id_build (fp + 8, frame_pc_unwind (next_frame)); 909} 910 911#ifdef USE_PROC_FS /* Target dependent support for /proc */ 912 913#include <sys/procfs.h> 914 915/* Prototypes for supply_gregset etc. */ 916#include "gregset.h" 917 918/* The /proc interface divides the target machine's register set up into 919 two different sets, the general register set (gregset) and the floating 920 point register set (fpregset). For each set, there is an ioctl to get 921 the current register set and another ioctl to set the current values. 922 923 The actual structure passed through the ioctl interface is, of course, 924 naturally machine dependent, and is different for each set of registers. 925 For the m68k for example, the general register set is typically defined 926 by: 927 928 typedef int gregset_t[18]; 929 930 #define R_D0 0 931 ... 932 #define R_PS 17 933 934 and the floating point set by: 935 936 typedef struct fpregset { 937 int f_pcr; 938 int f_psr; 939 int f_fpiaddr; 940 int f_fpregs[8][3]; (8 regs, 96 bits each) 941 } fpregset_t; 942 943 These routines provide the packing and unpacking of gregset_t and 944 fpregset_t formatted data. 945 946 */ 947 948/* Atari SVR4 has R_SR but not R_PS */ 949 950#if !defined (R_PS) && defined (R_SR) 951#define R_PS R_SR 952#endif 953 954/* Given a pointer to a general register set in /proc format (gregset_t *), 955 unpack the register contents and supply them as gdb's idea of the current 956 register values. */ 957 958void 959supply_gregset (gregset_t *gregsetp) 960{ 961 int regi; 962 greg_t *regp = (greg_t *) gregsetp; 963 964 for (regi = 0; regi < R_PC; regi++) 965 { 966 regcache_raw_supply (current_regcache, regi, (char *) (regp + regi)); 967 } 968 regcache_raw_supply (current_regcache, PS_REGNUM, (char *) (regp + R_PS)); 969 regcache_raw_supply (current_regcache, PC_REGNUM, (char *) (regp + R_PC)); 970} 971 972void 973fill_gregset (gregset_t *gregsetp, int regno) 974{ 975 int regi; 976 greg_t *regp = (greg_t *) gregsetp; 977 978 for (regi = 0; regi < R_PC; regi++) 979 { 980 if (regno == -1 || regno == regi) 981 regcache_raw_collect (current_regcache, regi, regp + regi); 982 } 983 if (regno == -1 || regno == PS_REGNUM) 984 regcache_raw_collect (current_regcache, PS_REGNUM, regp + R_PS); 985 if (regno == -1 || regno == PC_REGNUM) 986 regcache_raw_collect (current_regcache, PC_REGNUM, regp + R_PC); 987} 988 989#if defined (FP0_REGNUM) 990 991/* Given a pointer to a floating point register set in /proc format 992 (fpregset_t *), unpack the register contents and supply them as gdb's 993 idea of the current floating point register values. */ 994 995void 996supply_fpregset (fpregset_t *fpregsetp) 997{ 998 int regi; 999 char *from; 1000 1001 for (regi = FP0_REGNUM; regi < M68K_FPC_REGNUM; regi++) 1002 { 1003 from = (char *) &(fpregsetp->f_fpregs[regi - FP0_REGNUM][0]); 1004 regcache_raw_supply (current_regcache, regi, from); 1005 } 1006 regcache_raw_supply (current_regcache, M68K_FPC_REGNUM, 1007 (char *) &(fpregsetp->f_pcr)); 1008 regcache_raw_supply (current_regcache, M68K_FPS_REGNUM, 1009 (char *) &(fpregsetp->f_psr)); 1010 regcache_raw_supply (current_regcache, M68K_FPI_REGNUM, 1011 (char *) &(fpregsetp->f_fpiaddr)); 1012} 1013 1014/* Given a pointer to a floating point register set in /proc format 1015 (fpregset_t *), update the register specified by REGNO from gdb's idea 1016 of the current floating point register set. If REGNO is -1, update 1017 them all. */ 1018 1019void 1020fill_fpregset (fpregset_t *fpregsetp, int regno) 1021{ 1022 int regi; 1023 1024 for (regi = FP0_REGNUM; regi < M68K_FPC_REGNUM; regi++) 1025 { 1026 if (regno == -1 || regno == regi) 1027 regcache_raw_collect (current_regcache, regi, 1028 &fpregsetp->f_fpregs[regi - FP0_REGNUM][0]); 1029 } 1030 if (regno == -1 || regno == M68K_FPC_REGNUM) 1031 regcache_raw_collect (current_regcache, M68K_FPC_REGNUM, 1032 &fpregsetp->f_pcr); 1033 if (regno == -1 || regno == M68K_FPS_REGNUM) 1034 regcache_raw_collect (current_regcache, M68K_FPS_REGNUM, 1035 &fpregsetp->f_psr); 1036 if (regno == -1 || regno == M68K_FPI_REGNUM) 1037 regcache_raw_collect (current_regcache, M68K_FPI_REGNUM, 1038 &fpregsetp->f_fpiaddr); 1039} 1040 1041#endif /* defined (FP0_REGNUM) */ 1042 1043#endif /* USE_PROC_FS */ 1044 1045/* Figure out where the longjmp will land. Slurp the args out of the stack. 1046 We expect the first arg to be a pointer to the jmp_buf structure from which 1047 we extract the pc (JB_PC) that we will land at. The pc is copied into PC. 1048 This routine returns true on success. */ 1049 1050static int 1051m68k_get_longjmp_target (CORE_ADDR *pc) 1052{ 1053 char *buf; 1054 CORE_ADDR sp, jb_addr; 1055 struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); 1056 1057 if (tdep->jb_pc < 0) 1058 { 1059 internal_error (__FILE__, __LINE__, 1060 "m68k_get_longjmp_target: not implemented"); 1061 return 0; 1062 } 1063 1064 buf = alloca (TARGET_PTR_BIT / TARGET_CHAR_BIT); 1065 sp = read_register (SP_REGNUM); 1066 1067 if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */ 1068 buf, TARGET_PTR_BIT / TARGET_CHAR_BIT)) 1069 return 0; 1070 1071 jb_addr = extract_unsigned_integer (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); 1072 1073 if (target_read_memory (jb_addr + tdep->jb_pc * tdep->jb_elt_size, buf, 1074 TARGET_PTR_BIT / TARGET_CHAR_BIT)) 1075 return 0; 1076 1077 *pc = extract_unsigned_integer (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); 1078 return 1; 1079} 1080 1081 1082/* System V Release 4 (SVR4). */ 1083 1084void 1085m68k_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 1086{ 1087 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 1088 1089 /* SVR4 uses a different calling convention. */ 1090 set_gdbarch_return_value (gdbarch, m68k_svr4_return_value); 1091 1092 /* SVR4 uses %a0 instead of %a1. */ 1093 tdep->struct_value_regnum = M68K_A0_REGNUM; 1094} 1095 1096 1097/* Function: m68k_gdbarch_init 1098 Initializer function for the m68k gdbarch vector. 1099 Called by gdbarch. Sets up the gdbarch vector(s) for this target. */ 1100 1101static struct gdbarch * 1102m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) 1103{ 1104 struct gdbarch_tdep *tdep = NULL; 1105 struct gdbarch *gdbarch; 1106 1107 /* find a candidate among the list of pre-declared architectures. */ 1108 arches = gdbarch_list_lookup_by_info (arches, &info); 1109 if (arches != NULL) 1110 return (arches->gdbarch); 1111 1112 tdep = xmalloc (sizeof (struct gdbarch_tdep)); 1113 gdbarch = gdbarch_alloc (&info, tdep); 1114 1115 set_gdbarch_long_double_format (gdbarch, &floatformat_m68881_ext); 1116 set_gdbarch_long_double_bit (gdbarch, 96); 1117 1118 set_gdbarch_skip_prologue (gdbarch, m68k_skip_prologue); 1119 set_gdbarch_breakpoint_from_pc (gdbarch, m68k_local_breakpoint_from_pc); 1120 1121 /* Stack grows down. */ 1122 set_gdbarch_inner_than (gdbarch, core_addr_lessthan); 1123 1124 set_gdbarch_believe_pcc_promotion (gdbarch, 1); 1125 set_gdbarch_decr_pc_after_break (gdbarch, 2); 1126 1127 set_gdbarch_frame_args_skip (gdbarch, 8); 1128 1129 set_gdbarch_register_type (gdbarch, m68k_register_type); 1130 set_gdbarch_register_name (gdbarch, m68k_register_name); 1131 set_gdbarch_num_regs (gdbarch, 29); 1132 set_gdbarch_register_bytes_ok (gdbarch, m68k_register_bytes_ok); 1133 set_gdbarch_sp_regnum (gdbarch, M68K_SP_REGNUM); 1134 set_gdbarch_pc_regnum (gdbarch, M68K_PC_REGNUM); 1135 set_gdbarch_ps_regnum (gdbarch, M68K_PS_REGNUM); 1136 set_gdbarch_fp0_regnum (gdbarch, M68K_FP0_REGNUM); 1137 set_gdbarch_convert_register_p (gdbarch, m68k_convert_register_p); 1138 set_gdbarch_register_to_value (gdbarch, m68k_register_to_value); 1139 set_gdbarch_value_to_register (gdbarch, m68k_value_to_register); 1140 1141 set_gdbarch_push_dummy_call (gdbarch, m68k_push_dummy_call); 1142 set_gdbarch_return_value (gdbarch, m68k_return_value); 1143 1144 /* Disassembler. */ 1145 set_gdbarch_print_insn (gdbarch, print_insn_m68k); 1146 1147#if defined JB_PC && defined JB_ELEMENT_SIZE 1148 tdep->jb_pc = JB_PC; 1149 tdep->jb_elt_size = JB_ELEMENT_SIZE; 1150#else 1151 tdep->jb_pc = -1; 1152#endif 1153 tdep->struct_value_regnum = M68K_A1_REGNUM; 1154 tdep->struct_return = reg_struct_return; 1155 1156 /* Frame unwinder. */ 1157 set_gdbarch_unwind_dummy_id (gdbarch, m68k_unwind_dummy_id); 1158 set_gdbarch_unwind_pc (gdbarch, m68k_unwind_pc); 1159 1160 /* Hook in the DWARF CFI frame unwinder. */ 1161 frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer); 1162 1163 frame_base_set_default (gdbarch, &m68k_frame_base); 1164 1165 /* Hook in ABI-specific overrides, if they have been registered. */ 1166 gdbarch_init_osabi (info, gdbarch); 1167 1168 /* Now we have tuned the configuration, set a few final things, 1169 based on what the OS ABI has told us. */ 1170 1171 if (tdep->jb_pc >= 0) 1172 set_gdbarch_get_longjmp_target (gdbarch, m68k_get_longjmp_target); 1173 1174 frame_unwind_append_sniffer (gdbarch, m68k_frame_sniffer); 1175 1176 return gdbarch; 1177} 1178 1179 1180static void 1181m68k_dump_tdep (struct gdbarch *current_gdbarch, struct ui_file *file) 1182{ 1183 struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); 1184 1185 if (tdep == NULL) 1186 return; 1187} 1188 1189extern initialize_file_ftype _initialize_m68k_tdep; /* -Wmissing-prototypes */ 1190 1191void 1192_initialize_m68k_tdep (void) 1193{ 1194 gdbarch_register (bfd_arch_m68k, m68k_gdbarch_init, m68k_dump_tdep); 1195} 1196