1 /* Target-dependent code for the Motorola 68000 series.
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1999, 2000, 2001,
4 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
5 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "dwarf2-frame.h"
25 #include "frame-base.h"
26 #include "frame-unwind.h"
31 #include "gdb_string.h"
32 #include "gdb_assert.h"
35 #include "arch-utils.h"
38 #include "target-descriptions.h"
40 #include "m68k-tdep.h"
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
57 /* Offset from SP to first arg on stack at first instruction of a function */
58 #define SP_ARG0 (1 * 4)
60 #if !defined (BPT_VECTOR)
61 #define BPT_VECTOR 0xf
64 static const gdb_byte *
65 m68k_local_breakpoint_from_pc (struct gdbarch *gdbarch,
66 CORE_ADDR *pcptr, int *lenptr)
68 static gdb_byte break_insn[] = {0x4e, (0x40 | BPT_VECTOR)};
69 *lenptr = sizeof (break_insn);
74 /* Construct types for ISA-specific registers. */
76 m68k_ps_type (struct gdbarch *gdbarch)
78 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
80 if (!tdep->m68k_ps_type)
84 type = arch_flags_type (gdbarch, "builtin_type_m68k_ps", 4);
85 append_flags_type_flag (type, 0, "C");
86 append_flags_type_flag (type, 1, "V");
87 append_flags_type_flag (type, 2, "Z");
88 append_flags_type_flag (type, 3, "N");
89 append_flags_type_flag (type, 4, "X");
90 append_flags_type_flag (type, 8, "I0");
91 append_flags_type_flag (type, 9, "I1");
92 append_flags_type_flag (type, 10, "I2");
93 append_flags_type_flag (type, 12, "M");
94 append_flags_type_flag (type, 13, "S");
95 append_flags_type_flag (type, 14, "T0");
96 append_flags_type_flag (type, 15, "T1");
98 tdep->m68k_ps_type = type;
101 return tdep->m68k_ps_type;
105 m68881_ext_type (struct gdbarch *gdbarch)
107 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
109 if (!tdep->m68881_ext_type)
110 tdep->m68881_ext_type
111 = arch_float_type (gdbarch, -1, "builtin_type_m68881_ext",
112 floatformats_m68881_ext);
114 return tdep->m68881_ext_type;
117 /* Return the GDB type object for the "standard" data type of data in
118 register N. This should be int for D0-D7, SR, FPCONTROL and
119 FPSTATUS, long double for FP0-FP7, and void pointer for all others
120 (A0-A7, PC, FPIADDR). Note, for registers which contain
121 addresses return pointer to void, not pointer to char, because we
122 don't want to attempt to print the string after printing the
126 m68k_register_type (struct gdbarch *gdbarch, int regnum)
128 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
130 if (tdep->fpregs_present)
132 if (regnum >= gdbarch_fp0_regnum (gdbarch)
133 && regnum <= gdbarch_fp0_regnum (gdbarch) + 7)
135 if (tdep->flavour == m68k_coldfire_flavour)
136 return builtin_type (gdbarch)->builtin_double;
138 return m68881_ext_type (gdbarch);
141 if (regnum == M68K_FPI_REGNUM)
142 return builtin_type (gdbarch)->builtin_func_ptr;
144 if (regnum == M68K_FPC_REGNUM || regnum == M68K_FPS_REGNUM)
145 return builtin_type (gdbarch)->builtin_int32;
149 if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM)
150 return builtin_type (gdbarch)->builtin_int0;
153 if (regnum == gdbarch_pc_regnum (gdbarch))
154 return builtin_type (gdbarch)->builtin_func_ptr;
156 if (regnum >= M68K_A0_REGNUM && regnum <= M68K_A0_REGNUM + 7)
157 return builtin_type (gdbarch)->builtin_data_ptr;
159 if (regnum == M68K_PS_REGNUM)
160 return m68k_ps_type (gdbarch);
162 return builtin_type (gdbarch)->builtin_int32;
165 static const char *m68k_register_names[] = {
166 "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7",
167 "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp",
169 "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7",
170 "fpcontrol", "fpstatus", "fpiaddr"
173 /* Function: m68k_register_name
174 Returns the name of the standard m68k register regnum. */
177 m68k_register_name (struct gdbarch *gdbarch, int regnum)
179 if (regnum < 0 || regnum >= ARRAY_SIZE (m68k_register_names))
180 internal_error (__FILE__, __LINE__,
181 _("m68k_register_name: illegal register number %d"), regnum);
183 return m68k_register_names[regnum];
186 /* Return nonzero if a value of type TYPE stored in register REGNUM
187 needs any special handling. */
190 m68k_convert_register_p (struct gdbarch *gdbarch, int regnum, struct type *type)
192 if (!gdbarch_tdep (gdbarch)->fpregs_present)
194 return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7
195 && type != m68881_ext_type (gdbarch)
196 && type != register_type (gdbarch, M68K_FP0_REGNUM));
199 /* Read a value of type TYPE from register REGNUM in frame FRAME, and
200 return its contents in TO. */
203 m68k_register_to_value (struct frame_info *frame, int regnum,
204 struct type *type, gdb_byte *to)
206 gdb_byte from[M68K_MAX_REGISTER_SIZE];
207 struct type *fpreg_type = register_type (get_frame_arch (frame),
210 /* We only support floating-point values. */
211 if (TYPE_CODE (type) != TYPE_CODE_FLT)
213 warning (_("Cannot convert floating-point register value "
214 "to non-floating-point type."));
218 /* Convert to TYPE. */
219 get_frame_register (frame, regnum, from);
220 convert_typed_floating (from, fpreg_type, to, type);
223 /* Write the contents FROM of a value of type TYPE into register
224 REGNUM in frame FRAME. */
227 m68k_value_to_register (struct frame_info *frame, int regnum,
228 struct type *type, const gdb_byte *from)
230 gdb_byte to[M68K_MAX_REGISTER_SIZE];
231 struct type *fpreg_type = register_type (get_frame_arch (frame),
234 /* We only support floating-point values. */
235 if (TYPE_CODE (type) != TYPE_CODE_FLT)
237 warning (_("Cannot convert non-floating-point type "
238 "to floating-point register value."));
242 /* Convert from TYPE. */
243 convert_typed_floating (from, type, to, fpreg_type);
244 put_frame_register (frame, regnum, to);
248 /* There is a fair number of calling conventions that are in somewhat
249 wide use. The 68000/08/10 don't support an FPU, not even as a
250 coprocessor. All function return values are stored in %d0/%d1.
251 Structures are returned in a static buffer, a pointer to which is
252 returned in %d0. This means that functions returning a structure
253 are not re-entrant. To avoid this problem some systems use a
254 convention where the caller passes a pointer to a buffer in %a1
255 where the return values is to be stored. This convention is the
256 default, and is implemented in the function m68k_return_value.
258 The 68020/030/040/060 do support an FPU, either as a coprocessor
259 (68881/2) or built-in (68040/68060). That's why System V release 4
260 (SVR4) instroduces a new calling convention specified by the SVR4
261 psABI. Integer values are returned in %d0/%d1, pointer return
262 values in %a0 and floating values in %fp0. When calling functions
263 returning a structure the caller should pass a pointer to a buffer
264 for the return value in %a0. This convention is implemented in the
265 function m68k_svr4_return_value, and by appropriately setting the
266 struct_value_regnum member of `struct gdbarch_tdep'.
268 GNU/Linux returns values in the same way as SVR4 does, but uses %a1
269 for passing the structure return value buffer.
271 GCC can also generate code where small structures are returned in
272 %d0/%d1 instead of in memory by using -freg-struct-return. This is
273 the default on NetBSD a.out, OpenBSD and GNU/Linux and several
274 embedded systems. This convention is implemented by setting the
275 struct_return member of `struct gdbarch_tdep' to reg_struct_return. */
277 /* Read a function return value of TYPE from REGCACHE, and copy that
281 m68k_extract_return_value (struct type *type, struct regcache *regcache,
284 int len = TYPE_LENGTH (type);
285 gdb_byte buf[M68K_MAX_REGISTER_SIZE];
289 regcache_raw_read (regcache, M68K_D0_REGNUM, buf);
290 memcpy (valbuf, buf + (4 - len), len);
294 regcache_raw_read (regcache, M68K_D0_REGNUM, buf);
295 memcpy (valbuf, buf + (8 - len), len - 4);
296 regcache_raw_read (regcache, M68K_D1_REGNUM, valbuf + (len - 4));
299 internal_error (__FILE__, __LINE__,
300 _("Cannot extract return value of %d bytes long."), len);
304 m68k_svr4_extract_return_value (struct type *type, struct regcache *regcache,
307 int len = TYPE_LENGTH (type);
308 gdb_byte buf[M68K_MAX_REGISTER_SIZE];
309 struct gdbarch *gdbarch = get_regcache_arch (regcache);
310 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
312 if (tdep->float_return && TYPE_CODE (type) == TYPE_CODE_FLT)
314 struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM);
315 regcache_raw_read (regcache, M68K_FP0_REGNUM, buf);
316 convert_typed_floating (buf, fpreg_type, valbuf, type);
318 else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)
319 regcache_raw_read (regcache, M68K_A0_REGNUM, valbuf);
321 m68k_extract_return_value (type, regcache, valbuf);
324 /* Write a function return value of TYPE from VALBUF into REGCACHE. */
327 m68k_store_return_value (struct type *type, struct regcache *regcache,
328 const gdb_byte *valbuf)
330 int len = TYPE_LENGTH (type);
333 regcache_raw_write_part (regcache, M68K_D0_REGNUM, 4 - len, len, valbuf);
336 regcache_raw_write_part (regcache, M68K_D0_REGNUM, 8 - len,
338 regcache_raw_write (regcache, M68K_D1_REGNUM, valbuf + (len - 4));
341 internal_error (__FILE__, __LINE__,
342 _("Cannot store return value of %d bytes long."), len);
346 m68k_svr4_store_return_value (struct type *type, struct regcache *regcache,
347 const gdb_byte *valbuf)
349 int len = TYPE_LENGTH (type);
350 struct gdbarch *gdbarch = get_regcache_arch (regcache);
351 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
353 if (tdep->float_return && TYPE_CODE (type) == TYPE_CODE_FLT)
355 struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM);
356 gdb_byte buf[M68K_MAX_REGISTER_SIZE];
357 convert_typed_floating (valbuf, type, buf, fpreg_type);
358 regcache_raw_write (regcache, M68K_FP0_REGNUM, buf);
360 else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)
362 regcache_raw_write (regcache, M68K_A0_REGNUM, valbuf);
363 regcache_raw_write (regcache, M68K_D0_REGNUM, valbuf);
366 m68k_store_return_value (type, regcache, valbuf);
369 /* Return non-zero if TYPE, which is assumed to be a structure or
370 union type, should be returned in registers for architecture
374 m68k_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type)
376 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
377 enum type_code code = TYPE_CODE (type);
378 int len = TYPE_LENGTH (type);
380 gdb_assert (code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION);
382 if (tdep->struct_return == pcc_struct_return)
385 return (len == 1 || len == 2 || len == 4 || len == 8);
388 /* Determine, for architecture GDBARCH, how a return value of TYPE
389 should be returned. If it is supposed to be returned in registers,
390 and READBUF is non-zero, read the appropriate value from REGCACHE,
391 and copy it into READBUF. If WRITEBUF is non-zero, write the value
392 from WRITEBUF into REGCACHE. */
394 static enum return_value_convention
395 m68k_return_value (struct gdbarch *gdbarch, struct type *func_type,
396 struct type *type, struct regcache *regcache,
397 gdb_byte *readbuf, const gdb_byte *writebuf)
399 enum type_code code = TYPE_CODE (type);
401 /* GCC returns a `long double' in memory too. */
402 if (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)
403 && !m68k_reg_struct_return_p (gdbarch, type))
404 || (code == TYPE_CODE_FLT && TYPE_LENGTH (type) == 12))
406 /* The default on m68k is to return structures in static memory.
407 Consequently a function must return the address where we can
408 find the return value. */
414 regcache_raw_read_unsigned (regcache, M68K_D0_REGNUM, &addr);
415 read_memory (addr, readbuf, TYPE_LENGTH (type));
418 return RETURN_VALUE_ABI_RETURNS_ADDRESS;
422 m68k_extract_return_value (type, regcache, readbuf);
424 m68k_store_return_value (type, regcache, writebuf);
426 return RETURN_VALUE_REGISTER_CONVENTION;
429 static enum return_value_convention
430 m68k_svr4_return_value (struct gdbarch *gdbarch, struct type *func_type,
431 struct type *type, struct regcache *regcache,
432 gdb_byte *readbuf, const gdb_byte *writebuf)
434 enum type_code code = TYPE_CODE (type);
436 if ((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)
437 && !m68k_reg_struct_return_p (gdbarch, type))
439 /* The System V ABI says that:
441 "A function returning a structure or union also sets %a0 to
442 the value it finds in %a0. Thus when the caller receives
443 control again, the address of the returned object resides in
446 So the ABI guarantees that we can always find the return
447 value just after the function has returned. */
453 regcache_raw_read_unsigned (regcache, M68K_A0_REGNUM, &addr);
454 read_memory (addr, readbuf, TYPE_LENGTH (type));
457 return RETURN_VALUE_ABI_RETURNS_ADDRESS;
460 /* This special case is for structures consisting of a single
461 `float' or `double' member. These structures are returned in
462 %fp0. For these structures, we call ourselves recursively,
463 changing TYPE into the type of the first member of the structure.
464 Since that should work for all structures that have only one
465 member, we don't bother to check the member's type here. */
466 if (code == TYPE_CODE_STRUCT && TYPE_NFIELDS (type) == 1)
468 type = check_typedef (TYPE_FIELD_TYPE (type, 0));
469 return m68k_svr4_return_value (gdbarch, func_type, type, regcache,
474 m68k_svr4_extract_return_value (type, regcache, readbuf);
476 m68k_svr4_store_return_value (type, regcache, writebuf);
478 return RETURN_VALUE_REGISTER_CONVENTION;
482 /* Always align the frame to a 4-byte boundary. This is required on
483 coldfire and harmless on the rest. */
486 m68k_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
488 /* Align the stack to four bytes. */
493 m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
494 struct regcache *regcache, CORE_ADDR bp_addr, int nargs,
495 struct value **args, CORE_ADDR sp, int struct_return,
496 CORE_ADDR struct_addr)
498 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
499 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
503 /* Push arguments in reverse order. */
504 for (i = nargs - 1; i >= 0; i--)
506 struct type *value_type = value_enclosing_type (args[i]);
507 int len = TYPE_LENGTH (value_type);
508 int container_len = (len + 3) & ~3;
511 /* Non-scalars bigger than 4 bytes are left aligned, others are
513 if ((TYPE_CODE (value_type) == TYPE_CODE_STRUCT
514 || TYPE_CODE (value_type) == TYPE_CODE_UNION
515 || TYPE_CODE (value_type) == TYPE_CODE_ARRAY)
519 offset = container_len - len;
521 write_memory (sp + offset, value_contents_all (args[i]), len);
524 /* Store struct value address. */
527 store_unsigned_integer (buf, 4, byte_order, struct_addr);
528 regcache_cooked_write (regcache, tdep->struct_value_regnum, buf);
531 /* Store return address. */
533 store_unsigned_integer (buf, 4, byte_order, bp_addr);
534 write_memory (sp, buf, 4);
536 /* Finally, update the stack pointer... */
537 store_unsigned_integer (buf, 4, byte_order, sp);
538 regcache_cooked_write (regcache, M68K_SP_REGNUM, buf);
540 /* ...and fake a frame pointer. */
541 regcache_cooked_write (regcache, M68K_FP_REGNUM, buf);
543 /* DWARF2/GCC uses the stack address *before* the function call as a
548 /* Convert a dwarf or dwarf2 regnumber to a GDB regnum. */
551 m68k_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int num)
555 return (num - 0) + M68K_D0_REGNUM;
558 return (num - 8) + M68K_A0_REGNUM;
559 else if (num < 24 && gdbarch_tdep (gdbarch)->fpregs_present)
561 return (num - 16) + M68K_FP0_REGNUM;
564 return M68K_PC_REGNUM;
566 return gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
570 struct m68k_frame_cache
577 /* Saved registers. */
578 CORE_ADDR saved_regs[M68K_NUM_REGS];
581 /* Stack space reserved for local variables. */
585 /* Allocate and initialize a frame cache. */
587 static struct m68k_frame_cache *
588 m68k_alloc_frame_cache (void)
590 struct m68k_frame_cache *cache;
593 cache = FRAME_OBSTACK_ZALLOC (struct m68k_frame_cache);
597 cache->sp_offset = -4;
600 /* Saved registers. We initialize these to -1 since zero is a valid
601 offset (that's where %fp is supposed to be stored). */
602 for (i = 0; i < M68K_NUM_REGS; i++)
603 cache->saved_regs[i] = -1;
605 /* Frameless until proven otherwise. */
611 /* Check whether PC points at a code that sets up a new stack frame.
612 If so, it updates CACHE and returns the address of the first
613 instruction after the sequence that sets removes the "hidden"
614 argument from the stack or CURRENT_PC, whichever is smaller.
615 Otherwise, return PC. */
618 m68k_analyze_frame_setup (struct gdbarch *gdbarch,
619 CORE_ADDR pc, CORE_ADDR current_pc,
620 struct m68k_frame_cache *cache)
622 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
625 if (pc >= current_pc)
628 op = read_memory_unsigned_integer (pc, 2, byte_order);
630 if (op == P_LINKW_FP || op == P_LINKL_FP || op == P_PEA_FP)
632 cache->saved_regs[M68K_FP_REGNUM] = 0;
633 cache->sp_offset += 4;
634 if (op == P_LINKW_FP)
636 /* link.w %fp, #-N */
637 /* link.w %fp, #0; adda.l #-N, %sp */
638 cache->locals = -read_memory_integer (pc + 2, 2, byte_order);
640 if (pc + 4 < current_pc && cache->locals == 0)
642 op = read_memory_unsigned_integer (pc + 4, 2, byte_order);
643 if (op == P_ADDAL_SP)
645 cache->locals = read_memory_integer (pc + 6, 4, byte_order);
652 else if (op == P_LINKL_FP)
654 /* link.l %fp, #-N */
655 cache->locals = -read_memory_integer (pc + 2, 4, byte_order);
660 /* pea (%fp); movea.l %sp, %fp */
663 if (pc + 2 < current_pc)
665 op = read_memory_unsigned_integer (pc + 2, 2, byte_order);
667 if (op == P_MOVEAL_SP_FP)
669 /* move.l %sp, %fp */
677 else if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP)
679 /* subq.[wl] #N,%sp */
680 /* subq.[wl] #8,%sp; subq.[wl] #N,%sp */
681 cache->locals = (op & 07000) == 0 ? 8 : (op & 07000) >> 9;
682 if (pc + 2 < current_pc)
684 op = read_memory_unsigned_integer (pc + 2, 2, byte_order);
685 if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP)
687 cache->locals += (op & 07000) == 0 ? 8 : (op & 07000) >> 9;
693 else if (op == P_ADDAW_SP || op == P_LEA_SP_SP)
696 /* lea (-N,%sp),%sp */
697 cache->locals = -read_memory_integer (pc + 2, 2, byte_order);
700 else if (op == P_ADDAL_SP)
703 cache->locals = -read_memory_integer (pc + 2, 4, byte_order);
710 /* Check whether PC points at code that saves registers on the stack.
711 If so, it updates CACHE and returns the address of the first
712 instruction after the register saves or CURRENT_PC, whichever is
713 smaller. Otherwise, return PC. */
716 m68k_analyze_register_saves (struct gdbarch *gdbarch, CORE_ADDR pc,
717 CORE_ADDR current_pc,
718 struct m68k_frame_cache *cache)
720 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
722 if (cache->locals >= 0)
728 offset = -4 - cache->locals;
729 while (pc < current_pc)
731 op = read_memory_unsigned_integer (pc, 2, byte_order);
732 if (op == P_FMOVEMX_SP
733 && gdbarch_tdep (gdbarch)->fpregs_present)
735 /* fmovem.x REGS,-(%sp) */
736 op = read_memory_unsigned_integer (pc + 2, 2, byte_order);
737 if ((op & 0xff00) == 0xe000)
740 for (i = 0; i < 16; i++, mask >>= 1)
744 cache->saved_regs[i + M68K_FP0_REGNUM] = offset;
753 else if ((op & 0177760) == P_MOVEL_SP)
755 /* move.l %R,-(%sp) */
757 cache->saved_regs[regno] = offset;
761 else if (op == P_MOVEML_SP)
763 /* movem.l REGS,-(%sp) */
764 mask = read_memory_unsigned_integer (pc + 2, 2, byte_order);
765 for (i = 0; i < 16; i++, mask >>= 1)
769 cache->saved_regs[15 - i] = offset;
784 /* Do a full analysis of the prologue at PC and update CACHE
785 accordingly. Bail out early if CURRENT_PC is reached. Return the
786 address where the analysis stopped.
788 We handle all cases that can be generated by gcc.
790 For allocating a stack frame:
794 pea (%fp); move.l %sp,%fp
795 link.w %a6,#0; add.l #-N,%sp
798 subq.w #8,%sp; subq.w #N-8,%sp
803 For saving registers:
807 move.l R1,-(%sp); move.l R2,-(%sp)
810 For setting up the PIC register:
817 m68k_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR pc,
818 CORE_ADDR current_pc, struct m68k_frame_cache *cache)
820 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
823 pc = m68k_analyze_frame_setup (gdbarch, pc, current_pc, cache);
824 pc = m68k_analyze_register_saves (gdbarch, pc, current_pc, cache);
825 if (pc >= current_pc)
828 /* Check for GOT setup. */
829 op = read_memory_unsigned_integer (pc, 4, byte_order);
830 if (op == P_LEA_PC_A5)
832 /* lea (%pc,N),%a5 */
839 /* Return PC of first real instruction. */
842 m68k_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
844 struct m68k_frame_cache cache;
849 pc = m68k_analyze_prologue (gdbarch, start_pc, (CORE_ADDR) -1, &cache);
850 if (cache.locals < 0)
856 m68k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
860 frame_unwind_register (next_frame, gdbarch_pc_regnum (gdbarch), buf);
861 return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
866 static struct m68k_frame_cache *
867 m68k_frame_cache (struct frame_info *this_frame, void **this_cache)
869 struct gdbarch *gdbarch = get_frame_arch (this_frame);
870 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
871 struct m68k_frame_cache *cache;
878 cache = m68k_alloc_frame_cache ();
881 /* In principle, for normal frames, %fp holds the frame pointer,
882 which holds the base address for the current stack frame.
883 However, for functions that don't need it, the frame pointer is
884 optional. For these "frameless" functions the frame pointer is
885 actually the frame pointer of the calling frame. Signal
886 trampolines are just a special case of a "frameless" function.
887 They (usually) share their frame pointer with the frame that was
888 in progress when the signal occurred. */
890 get_frame_register (this_frame, M68K_FP_REGNUM, buf);
891 cache->base = extract_unsigned_integer (buf, 4, byte_order);
892 if (cache->base == 0)
895 /* For normal frames, %pc is stored at 4(%fp). */
896 cache->saved_regs[M68K_PC_REGNUM] = 4;
898 cache->pc = get_frame_func (this_frame);
900 m68k_analyze_prologue (get_frame_arch (this_frame), cache->pc,
901 get_frame_pc (this_frame), cache);
903 if (cache->locals < 0)
905 /* We didn't find a valid frame, which means that CACHE->base
906 currently holds the frame pointer for our calling frame. If
907 we're at the start of a function, or somewhere half-way its
908 prologue, the function's frame probably hasn't been fully
909 setup yet. Try to reconstruct the base address for the stack
910 frame by looking at the stack pointer. For truly "frameless"
911 functions this might work too. */
913 get_frame_register (this_frame, M68K_SP_REGNUM, buf);
914 cache->base = extract_unsigned_integer (buf, 4, byte_order)
918 /* Now that we have the base address for the stack frame we can
919 calculate the value of %sp in the calling frame. */
920 cache->saved_sp = cache->base + 8;
922 /* Adjust all the saved registers such that they contain addresses
923 instead of offsets. */
924 for (i = 0; i < M68K_NUM_REGS; i++)
925 if (cache->saved_regs[i] != -1)
926 cache->saved_regs[i] += cache->base;
932 m68k_frame_this_id (struct frame_info *this_frame, void **this_cache,
933 struct frame_id *this_id)
935 struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache);
937 /* This marks the outermost frame. */
938 if (cache->base == 0)
941 /* See the end of m68k_push_dummy_call. */
942 *this_id = frame_id_build (cache->base + 8, cache->pc);
945 static struct value *
946 m68k_frame_prev_register (struct frame_info *this_frame, void **this_cache,
949 struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache);
951 gdb_assert (regnum >= 0);
953 if (regnum == M68K_SP_REGNUM && cache->saved_sp)
954 return frame_unwind_got_constant (this_frame, regnum, cache->saved_sp);
956 if (regnum < M68K_NUM_REGS && cache->saved_regs[regnum] != -1)
957 return frame_unwind_got_memory (this_frame, regnum,
958 cache->saved_regs[regnum]);
960 return frame_unwind_got_register (this_frame, regnum, regnum);
963 static const struct frame_unwind m68k_frame_unwind =
967 m68k_frame_prev_register,
969 default_frame_sniffer
973 m68k_frame_base_address (struct frame_info *this_frame, void **this_cache)
975 struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache);
980 static const struct frame_base m68k_frame_base =
983 m68k_frame_base_address,
984 m68k_frame_base_address,
985 m68k_frame_base_address
988 static struct frame_id
989 m68k_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
993 fp = get_frame_register_unsigned (this_frame, M68K_FP_REGNUM);
995 /* See the end of m68k_push_dummy_call. */
996 return frame_id_build (fp + 8, get_frame_pc (this_frame));
1000 /* Figure out where the longjmp will land. Slurp the args out of the stack.
1001 We expect the first arg to be a pointer to the jmp_buf structure from which
1002 we extract the pc (JB_PC) that we will land at. The pc is copied into PC.
1003 This routine returns true on success. */
1006 m68k_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
1009 CORE_ADDR sp, jb_addr;
1010 struct gdbarch *gdbarch = get_frame_arch (frame);
1011 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
1012 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1014 if (tdep->jb_pc < 0)
1016 internal_error (__FILE__, __LINE__,
1017 _("m68k_get_longjmp_target: not implemented"));
1021 buf = alloca (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT);
1022 sp = get_frame_register_unsigned (frame, gdbarch_sp_regnum (gdbarch));
1024 if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */
1025 buf, gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT))
1028 jb_addr = extract_unsigned_integer (buf, gdbarch_ptr_bit (gdbarch)
1029 / TARGET_CHAR_BIT, byte_order);
1031 if (target_read_memory (jb_addr + tdep->jb_pc * tdep->jb_elt_size, buf,
1032 gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT),
1036 *pc = extract_unsigned_integer (buf, gdbarch_ptr_bit (gdbarch)
1037 / TARGET_CHAR_BIT, byte_order);
1042 /* System V Release 4 (SVR4). */
1045 m68k_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
1047 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
1049 /* SVR4 uses a different calling convention. */
1050 set_gdbarch_return_value (gdbarch, m68k_svr4_return_value);
1052 /* SVR4 uses %a0 instead of %a1. */
1053 tdep->struct_value_regnum = M68K_A0_REGNUM;
1057 /* Function: m68k_gdbarch_init
1058 Initializer function for the m68k gdbarch vector.
1059 Called by gdbarch. Sets up the gdbarch vector(s) for this target. */
1061 static struct gdbarch *
1062 m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
1064 struct gdbarch_tdep *tdep = NULL;
1065 struct gdbarch *gdbarch;
1066 struct gdbarch_list *best_arch;
1067 struct tdesc_arch_data *tdesc_data = NULL;
1069 enum m68k_flavour flavour = m68k_no_flavour;
1071 const struct floatformat **long_double_format = floatformats_m68881_ext;
1073 /* Check any target description for validity. */
1074 if (tdesc_has_registers (info.target_desc))
1076 const struct tdesc_feature *feature;
1079 feature = tdesc_find_feature (info.target_desc,
1080 "org.gnu.gdb.m68k.core");
1081 if (feature != NULL)
1085 if (feature == NULL)
1087 feature = tdesc_find_feature (info.target_desc,
1088 "org.gnu.gdb.coldfire.core");
1089 if (feature != NULL)
1090 flavour = m68k_coldfire_flavour;
1093 if (feature == NULL)
1095 feature = tdesc_find_feature (info.target_desc,
1096 "org.gnu.gdb.fido.core");
1097 if (feature != NULL)
1098 flavour = m68k_fido_flavour;
1101 if (feature == NULL)
1104 tdesc_data = tdesc_data_alloc ();
1107 for (i = 0; i <= M68K_PC_REGNUM; i++)
1108 valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
1109 m68k_register_names[i]);
1113 tdesc_data_cleanup (tdesc_data);
1117 feature = tdesc_find_feature (info.target_desc,
1118 "org.gnu.gdb.coldfire.fp");
1119 if (feature != NULL)
1122 for (i = M68K_FP0_REGNUM; i <= M68K_FPI_REGNUM; i++)
1123 valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
1124 m68k_register_names[i]);
1127 tdesc_data_cleanup (tdesc_data);
1135 /* The mechanism for returning floating values from function
1136 and the type of long double depend on whether we're
1137 on ColdFire or standard m68k. */
1139 if (info.bfd_arch_info && info.bfd_arch_info->mach != 0)
1141 const bfd_arch_info_type *coldfire_arch =
1142 bfd_lookup_arch (bfd_arch_m68k, bfd_mach_mcf_isa_a_nodiv);
1145 && ((*info.bfd_arch_info->compatible)
1146 (info.bfd_arch_info, coldfire_arch)))
1147 flavour = m68k_coldfire_flavour;
1150 /* If there is already a candidate, use it. */
1151 for (best_arch = gdbarch_list_lookup_by_info (arches, &info);
1153 best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
1155 if (flavour != gdbarch_tdep (best_arch->gdbarch)->flavour)
1158 if (has_fp != gdbarch_tdep (best_arch->gdbarch)->fpregs_present)
1164 tdep = xzalloc (sizeof (struct gdbarch_tdep));
1165 gdbarch = gdbarch_alloc (&info, tdep);
1166 tdep->fpregs_present = has_fp;
1167 tdep->flavour = flavour;
1169 if (flavour == m68k_coldfire_flavour || flavour == m68k_fido_flavour)
1170 long_double_format = floatformats_ieee_double;
1171 set_gdbarch_long_double_format (gdbarch, long_double_format);
1172 set_gdbarch_long_double_bit (gdbarch, long_double_format[0]->totalsize);
1174 set_gdbarch_skip_prologue (gdbarch, m68k_skip_prologue);
1175 set_gdbarch_breakpoint_from_pc (gdbarch, m68k_local_breakpoint_from_pc);
1177 /* Stack grows down. */
1178 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
1179 set_gdbarch_frame_align (gdbarch, m68k_frame_align);
1181 set_gdbarch_believe_pcc_promotion (gdbarch, 1);
1182 if (flavour == m68k_coldfire_flavour || flavour == m68k_fido_flavour)
1183 set_gdbarch_decr_pc_after_break (gdbarch, 2);
1185 set_gdbarch_frame_args_skip (gdbarch, 8);
1186 set_gdbarch_dwarf2_reg_to_regnum (gdbarch, m68k_dwarf_reg_to_regnum);
1188 set_gdbarch_register_type (gdbarch, m68k_register_type);
1189 set_gdbarch_register_name (gdbarch, m68k_register_name);
1190 set_gdbarch_num_regs (gdbarch, M68K_NUM_REGS);
1191 set_gdbarch_sp_regnum (gdbarch, M68K_SP_REGNUM);
1192 set_gdbarch_pc_regnum (gdbarch, M68K_PC_REGNUM);
1193 set_gdbarch_ps_regnum (gdbarch, M68K_PS_REGNUM);
1194 set_gdbarch_fp0_regnum (gdbarch, M68K_FP0_REGNUM);
1195 set_gdbarch_convert_register_p (gdbarch, m68k_convert_register_p);
1196 set_gdbarch_register_to_value (gdbarch, m68k_register_to_value);
1197 set_gdbarch_value_to_register (gdbarch, m68k_value_to_register);
1200 set_gdbarch_fp0_regnum (gdbarch, M68K_FP0_REGNUM);
1202 /* Try to figure out if the arch uses floating registers to return
1203 floating point values from functions. */
1206 /* On ColdFire, floating point values are returned in D0. */
1207 if (flavour == m68k_coldfire_flavour)
1208 tdep->float_return = 0;
1210 tdep->float_return = 1;
1214 /* No floating registers, so can't use them for returning values. */
1215 tdep->float_return = 0;
1218 /* Function call & return */
1219 set_gdbarch_push_dummy_call (gdbarch, m68k_push_dummy_call);
1220 set_gdbarch_return_value (gdbarch, m68k_return_value);
1224 set_gdbarch_print_insn (gdbarch, print_insn_m68k);
1226 #if defined JB_PC && defined JB_ELEMENT_SIZE
1227 tdep->jb_pc = JB_PC;
1228 tdep->jb_elt_size = JB_ELEMENT_SIZE;
1232 tdep->struct_value_regnum = M68K_A1_REGNUM;
1233 tdep->struct_return = reg_struct_return;
1235 /* Frame unwinder. */
1236 set_gdbarch_dummy_id (gdbarch, m68k_dummy_id);
1237 set_gdbarch_unwind_pc (gdbarch, m68k_unwind_pc);
1239 /* Hook in the DWARF CFI frame unwinder. */
1240 dwarf2_append_unwinders (gdbarch);
1242 frame_base_set_default (gdbarch, &m68k_frame_base);
1244 /* Hook in ABI-specific overrides, if they have been registered. */
1245 gdbarch_init_osabi (info, gdbarch);
1247 /* Now we have tuned the configuration, set a few final things,
1248 based on what the OS ABI has told us. */
1250 if (tdep->jb_pc >= 0)
1251 set_gdbarch_get_longjmp_target (gdbarch, m68k_get_longjmp_target);
1253 frame_unwind_append_unwinder (gdbarch, &m68k_frame_unwind);
1256 tdesc_use_registers (gdbarch, info.target_desc, tdesc_data);
1263 m68k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
1265 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
1271 extern initialize_file_ftype _initialize_m68k_tdep; /* -Wmissing-prototypes */
1274 _initialize_m68k_tdep (void)
1276 gdbarch_register (bfd_arch_m68k, m68k_gdbarch_init, m68k_dump_tdep);