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);
75 struct type *m68k_ps_type;
77 /* Construct types for ISA-specific registers. */
79 m68k_init_types (void)
83 type = init_flags_type ("builtin_type_m68k_ps", 4);
84 append_flags_type_flag (type, 0, "C");
85 append_flags_type_flag (type, 1, "V");
86 append_flags_type_flag (type, 2, "Z");
87 append_flags_type_flag (type, 3, "N");
88 append_flags_type_flag (type, 4, "X");
89 append_flags_type_flag (type, 8, "I0");
90 append_flags_type_flag (type, 9, "I1");
91 append_flags_type_flag (type, 10, "I2");
92 append_flags_type_flag (type, 12, "M");
93 append_flags_type_flag (type, 13, "S");
94 append_flags_type_flag (type, 14, "T0");
95 append_flags_type_flag (type, 15, "T1");
99 /* Return the GDB type object for the "standard" data type of data in
100 register N. This should be int for D0-D7, SR, FPCONTROL and
101 FPSTATUS, long double for FP0-FP7, and void pointer for all others
102 (A0-A7, PC, FPIADDR). Note, for registers which contain
103 addresses return pointer to void, not pointer to char, because we
104 don't want to attempt to print the string after printing the
108 m68k_register_type (struct gdbarch *gdbarch, int regnum)
110 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
112 if (tdep->fpregs_present)
114 if (regnum >= gdbarch_fp0_regnum (gdbarch)
115 && regnum <= gdbarch_fp0_regnum (gdbarch) + 7)
117 if (tdep->flavour == m68k_coldfire_flavour)
118 return builtin_type (gdbarch)->builtin_double;
120 return builtin_type_m68881_ext;
123 if (regnum == M68K_FPI_REGNUM)
124 return builtin_type (gdbarch)->builtin_func_ptr;
126 if (regnum == M68K_FPC_REGNUM || regnum == M68K_FPS_REGNUM)
127 return builtin_type_int32;
131 if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM)
132 return builtin_type_int0;
135 if (regnum == gdbarch_pc_regnum (gdbarch))
136 return builtin_type (gdbarch)->builtin_func_ptr;
138 if (regnum >= M68K_A0_REGNUM && regnum <= M68K_A0_REGNUM + 7)
139 return builtin_type (gdbarch)->builtin_data_ptr;
141 if (regnum == M68K_PS_REGNUM)
144 return builtin_type_int32;
147 static const char *m68k_register_names[] = {
148 "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7",
149 "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp",
151 "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7",
152 "fpcontrol", "fpstatus", "fpiaddr"
155 /* Function: m68k_register_name
156 Returns the name of the standard m68k register regnum. */
159 m68k_register_name (struct gdbarch *gdbarch, int regnum)
161 if (regnum < 0 || regnum >= ARRAY_SIZE (m68k_register_names))
162 internal_error (__FILE__, __LINE__,
163 _("m68k_register_name: illegal register number %d"), regnum);
165 return m68k_register_names[regnum];
168 /* Return nonzero if a value of type TYPE stored in register REGNUM
169 needs any special handling. */
172 m68k_convert_register_p (struct gdbarch *gdbarch, int regnum, struct type *type)
174 if (!gdbarch_tdep (gdbarch)->fpregs_present)
176 return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7
177 && type != builtin_type_m68881_ext);
180 /* Read a value of type TYPE from register REGNUM in frame FRAME, and
181 return its contents in TO. */
184 m68k_register_to_value (struct frame_info *frame, int regnum,
185 struct type *type, gdb_byte *to)
187 gdb_byte from[M68K_MAX_REGISTER_SIZE];
188 struct type *fpreg_type = register_type (get_frame_arch (frame),
191 /* We only support floating-point values. */
192 if (TYPE_CODE (type) != TYPE_CODE_FLT)
194 warning (_("Cannot convert floating-point register value "
195 "to non-floating-point type."));
199 /* Convert to TYPE. */
200 get_frame_register (frame, regnum, from);
201 convert_typed_floating (from, fpreg_type, to, type);
204 /* Write the contents FROM of a value of type TYPE into register
205 REGNUM in frame FRAME. */
208 m68k_value_to_register (struct frame_info *frame, int regnum,
209 struct type *type, const gdb_byte *from)
211 gdb_byte to[M68K_MAX_REGISTER_SIZE];
212 struct type *fpreg_type = register_type (get_frame_arch (frame),
215 /* We only support floating-point values. */
216 if (TYPE_CODE (type) != TYPE_CODE_FLT)
218 warning (_("Cannot convert non-floating-point type "
219 "to floating-point register value."));
223 /* Convert from TYPE. */
224 convert_typed_floating (from, type, to, fpreg_type);
225 put_frame_register (frame, regnum, to);
229 /* There is a fair number of calling conventions that are in somewhat
230 wide use. The 68000/08/10 don't support an FPU, not even as a
231 coprocessor. All function return values are stored in %d0/%d1.
232 Structures are returned in a static buffer, a pointer to which is
233 returned in %d0. This means that functions returning a structure
234 are not re-entrant. To avoid this problem some systems use a
235 convention where the caller passes a pointer to a buffer in %a1
236 where the return values is to be stored. This convention is the
237 default, and is implemented in the function m68k_return_value.
239 The 68020/030/040/060 do support an FPU, either as a coprocessor
240 (68881/2) or built-in (68040/68060). That's why System V release 4
241 (SVR4) instroduces a new calling convention specified by the SVR4
242 psABI. Integer values are returned in %d0/%d1, pointer return
243 values in %a0 and floating values in %fp0. When calling functions
244 returning a structure the caller should pass a pointer to a buffer
245 for the return value in %a0. This convention is implemented in the
246 function m68k_svr4_return_value, and by appropriately setting the
247 struct_value_regnum member of `struct gdbarch_tdep'.
249 GNU/Linux returns values in the same way as SVR4 does, but uses %a1
250 for passing the structure return value buffer.
252 GCC can also generate code where small structures are returned in
253 %d0/%d1 instead of in memory by using -freg-struct-return. This is
254 the default on NetBSD a.out, OpenBSD and GNU/Linux and several
255 embedded systems. This convention is implemented by setting the
256 struct_return member of `struct gdbarch_tdep' to reg_struct_return. */
258 /* Read a function return value of TYPE from REGCACHE, and copy that
262 m68k_extract_return_value (struct type *type, struct regcache *regcache,
265 int len = TYPE_LENGTH (type);
266 gdb_byte buf[M68K_MAX_REGISTER_SIZE];
270 regcache_raw_read (regcache, M68K_D0_REGNUM, buf);
271 memcpy (valbuf, buf + (4 - len), len);
275 regcache_raw_read (regcache, M68K_D0_REGNUM, buf);
276 memcpy (valbuf, buf + (8 - len), len - 4);
277 regcache_raw_read (regcache, M68K_D1_REGNUM, valbuf + (len - 4));
280 internal_error (__FILE__, __LINE__,
281 _("Cannot extract return value of %d bytes long."), len);
285 m68k_svr4_extract_return_value (struct type *type, struct regcache *regcache,
288 int len = TYPE_LENGTH (type);
289 gdb_byte buf[M68K_MAX_REGISTER_SIZE];
290 struct gdbarch *gdbarch = get_regcache_arch (regcache);
291 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
293 if (tdep->float_return && TYPE_CODE (type) == TYPE_CODE_FLT)
295 struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM);
296 regcache_raw_read (regcache, M68K_FP0_REGNUM, buf);
297 convert_typed_floating (buf, fpreg_type, valbuf, type);
299 else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)
300 regcache_raw_read (regcache, M68K_A0_REGNUM, valbuf);
302 m68k_extract_return_value (type, regcache, valbuf);
305 /* Write a function return value of TYPE from VALBUF into REGCACHE. */
308 m68k_store_return_value (struct type *type, struct regcache *regcache,
309 const gdb_byte *valbuf)
311 int len = TYPE_LENGTH (type);
314 regcache_raw_write_part (regcache, M68K_D0_REGNUM, 4 - len, len, valbuf);
317 regcache_raw_write_part (regcache, M68K_D0_REGNUM, 8 - len,
319 regcache_raw_write (regcache, M68K_D1_REGNUM, valbuf + (len - 4));
322 internal_error (__FILE__, __LINE__,
323 _("Cannot store return value of %d bytes long."), len);
327 m68k_svr4_store_return_value (struct type *type, struct regcache *regcache,
328 const gdb_byte *valbuf)
330 int len = TYPE_LENGTH (type);
331 struct gdbarch *gdbarch = get_regcache_arch (regcache);
332 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
334 if (tdep->float_return && TYPE_CODE (type) == TYPE_CODE_FLT)
336 struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM);
337 gdb_byte buf[M68K_MAX_REGISTER_SIZE];
338 convert_typed_floating (valbuf, type, buf, fpreg_type);
339 regcache_raw_write (regcache, M68K_FP0_REGNUM, buf);
341 else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)
343 regcache_raw_write (regcache, M68K_A0_REGNUM, valbuf);
344 regcache_raw_write (regcache, M68K_D0_REGNUM, valbuf);
347 m68k_store_return_value (type, regcache, valbuf);
350 /* Return non-zero if TYPE, which is assumed to be a structure or
351 union type, should be returned in registers for architecture
355 m68k_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type)
357 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
358 enum type_code code = TYPE_CODE (type);
359 int len = TYPE_LENGTH (type);
361 gdb_assert (code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION);
363 if (tdep->struct_return == pcc_struct_return)
366 return (len == 1 || len == 2 || len == 4 || len == 8);
369 /* Determine, for architecture GDBARCH, how a return value of TYPE
370 should be returned. If it is supposed to be returned in registers,
371 and READBUF is non-zero, read the appropriate value from REGCACHE,
372 and copy it into READBUF. If WRITEBUF is non-zero, write the value
373 from WRITEBUF into REGCACHE. */
375 static enum return_value_convention
376 m68k_return_value (struct gdbarch *gdbarch, struct type *func_type,
377 struct type *type, struct regcache *regcache,
378 gdb_byte *readbuf, const gdb_byte *writebuf)
380 enum type_code code = TYPE_CODE (type);
382 /* GCC returns a `long double' in memory too. */
383 if (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)
384 && !m68k_reg_struct_return_p (gdbarch, type))
385 || (code == TYPE_CODE_FLT && TYPE_LENGTH (type) == 12))
387 /* The default on m68k is to return structures in static memory.
388 Consequently a function must return the address where we can
389 find the return value. */
395 regcache_raw_read_unsigned (regcache, M68K_D0_REGNUM, &addr);
396 read_memory (addr, readbuf, TYPE_LENGTH (type));
399 return RETURN_VALUE_ABI_RETURNS_ADDRESS;
403 m68k_extract_return_value (type, regcache, readbuf);
405 m68k_store_return_value (type, regcache, writebuf);
407 return RETURN_VALUE_REGISTER_CONVENTION;
410 static enum return_value_convention
411 m68k_svr4_return_value (struct gdbarch *gdbarch, struct type *func_type,
412 struct type *type, struct regcache *regcache,
413 gdb_byte *readbuf, const gdb_byte *writebuf)
415 enum type_code code = TYPE_CODE (type);
417 if ((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)
418 && !m68k_reg_struct_return_p (gdbarch, type))
420 /* The System V ABI says that:
422 "A function returning a structure or union also sets %a0 to
423 the value it finds in %a0. Thus when the caller receives
424 control again, the address of the returned object resides in
427 So the ABI guarantees that we can always find the return
428 value just after the function has returned. */
434 regcache_raw_read_unsigned (regcache, M68K_A0_REGNUM, &addr);
435 read_memory (addr, readbuf, TYPE_LENGTH (type));
438 return RETURN_VALUE_ABI_RETURNS_ADDRESS;
441 /* This special case is for structures consisting of a single
442 `float' or `double' member. These structures are returned in
443 %fp0. For these structures, we call ourselves recursively,
444 changing TYPE into the type of the first member of the structure.
445 Since that should work for all structures that have only one
446 member, we don't bother to check the member's type here. */
447 if (code == TYPE_CODE_STRUCT && TYPE_NFIELDS (type) == 1)
449 type = check_typedef (TYPE_FIELD_TYPE (type, 0));
450 return m68k_svr4_return_value (gdbarch, func_type, type, regcache,
455 m68k_svr4_extract_return_value (type, regcache, readbuf);
457 m68k_svr4_store_return_value (type, regcache, writebuf);
459 return RETURN_VALUE_REGISTER_CONVENTION;
463 /* Always align the frame to a 4-byte boundary. This is required on
464 coldfire and harmless on the rest. */
467 m68k_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
469 /* Align the stack to four bytes. */
474 m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
475 struct regcache *regcache, CORE_ADDR bp_addr, int nargs,
476 struct value **args, CORE_ADDR sp, int struct_return,
477 CORE_ADDR struct_addr)
479 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
483 /* Push arguments in reverse order. */
484 for (i = nargs - 1; i >= 0; i--)
486 struct type *value_type = value_enclosing_type (args[i]);
487 int len = TYPE_LENGTH (value_type);
488 int container_len = (len + 3) & ~3;
491 /* Non-scalars bigger than 4 bytes are left aligned, others are
493 if ((TYPE_CODE (value_type) == TYPE_CODE_STRUCT
494 || TYPE_CODE (value_type) == TYPE_CODE_UNION
495 || TYPE_CODE (value_type) == TYPE_CODE_ARRAY)
499 offset = container_len - len;
501 write_memory (sp + offset, value_contents_all (args[i]), len);
504 /* Store struct value address. */
507 store_unsigned_integer (buf, 4, struct_addr);
508 regcache_cooked_write (regcache, tdep->struct_value_regnum, buf);
511 /* Store return address. */
513 store_unsigned_integer (buf, 4, bp_addr);
514 write_memory (sp, buf, 4);
516 /* Finally, update the stack pointer... */
517 store_unsigned_integer (buf, 4, sp);
518 regcache_cooked_write (regcache, M68K_SP_REGNUM, buf);
520 /* ...and fake a frame pointer. */
521 regcache_cooked_write (regcache, M68K_FP_REGNUM, buf);
523 /* DWARF2/GCC uses the stack address *before* the function call as a
528 /* Convert a dwarf or dwarf2 regnumber to a GDB regnum. */
531 m68k_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int num)
535 return (num - 0) + M68K_D0_REGNUM;
538 return (num - 8) + M68K_A0_REGNUM;
539 else if (num < 24 && gdbarch_tdep (gdbarch)->fpregs_present)
541 return (num - 16) + M68K_FP0_REGNUM;
544 return M68K_PC_REGNUM;
546 return gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
550 struct m68k_frame_cache
557 /* Saved registers. */
558 CORE_ADDR saved_regs[M68K_NUM_REGS];
561 /* Stack space reserved for local variables. */
565 /* Allocate and initialize a frame cache. */
567 static struct m68k_frame_cache *
568 m68k_alloc_frame_cache (void)
570 struct m68k_frame_cache *cache;
573 cache = FRAME_OBSTACK_ZALLOC (struct m68k_frame_cache);
577 cache->sp_offset = -4;
580 /* Saved registers. We initialize these to -1 since zero is a valid
581 offset (that's where %fp is supposed to be stored). */
582 for (i = 0; i < M68K_NUM_REGS; i++)
583 cache->saved_regs[i] = -1;
585 /* Frameless until proven otherwise. */
591 /* Check whether PC points at a code that sets up a new stack frame.
592 If so, it updates CACHE and returns the address of the first
593 instruction after the sequence that sets removes the "hidden"
594 argument from the stack or CURRENT_PC, whichever is smaller.
595 Otherwise, return PC. */
598 m68k_analyze_frame_setup (CORE_ADDR pc, CORE_ADDR current_pc,
599 struct m68k_frame_cache *cache)
603 if (pc >= current_pc)
606 op = read_memory_unsigned_integer (pc, 2);
608 if (op == P_LINKW_FP || op == P_LINKL_FP || op == P_PEA_FP)
610 cache->saved_regs[M68K_FP_REGNUM] = 0;
611 cache->sp_offset += 4;
612 if (op == P_LINKW_FP)
614 /* link.w %fp, #-N */
615 /* link.w %fp, #0; adda.l #-N, %sp */
616 cache->locals = -read_memory_integer (pc + 2, 2);
618 if (pc + 4 < current_pc && cache->locals == 0)
620 op = read_memory_unsigned_integer (pc + 4, 2);
621 if (op == P_ADDAL_SP)
623 cache->locals = read_memory_integer (pc + 6, 4);
630 else if (op == P_LINKL_FP)
632 /* link.l %fp, #-N */
633 cache->locals = -read_memory_integer (pc + 2, 4);
638 /* pea (%fp); movea.l %sp, %fp */
641 if (pc + 2 < current_pc)
643 op = read_memory_unsigned_integer (pc + 2, 2);
645 if (op == P_MOVEAL_SP_FP)
647 /* move.l %sp, %fp */
655 else if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP)
657 /* subq.[wl] #N,%sp */
658 /* subq.[wl] #8,%sp; subq.[wl] #N,%sp */
659 cache->locals = (op & 07000) == 0 ? 8 : (op & 07000) >> 9;
660 if (pc + 2 < current_pc)
662 op = read_memory_unsigned_integer (pc + 2, 2);
663 if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP)
665 cache->locals += (op & 07000) == 0 ? 8 : (op & 07000) >> 9;
671 else if (op == P_ADDAW_SP || op == P_LEA_SP_SP)
674 /* lea (-N,%sp),%sp */
675 cache->locals = -read_memory_integer (pc + 2, 2);
678 else if (op == P_ADDAL_SP)
681 cache->locals = -read_memory_integer (pc + 2, 4);
688 /* Check whether PC points at code that saves registers on the stack.
689 If so, it updates CACHE and returns the address of the first
690 instruction after the register saves or CURRENT_PC, whichever is
691 smaller. Otherwise, return PC. */
694 m68k_analyze_register_saves (struct gdbarch *gdbarch, CORE_ADDR pc,
695 CORE_ADDR current_pc,
696 struct m68k_frame_cache *cache)
698 if (cache->locals >= 0)
704 offset = -4 - cache->locals;
705 while (pc < current_pc)
707 op = read_memory_unsigned_integer (pc, 2);
708 if (op == P_FMOVEMX_SP
709 && gdbarch_tdep (gdbarch)->fpregs_present)
711 /* fmovem.x REGS,-(%sp) */
712 op = read_memory_unsigned_integer (pc + 2, 2);
713 if ((op & 0xff00) == 0xe000)
716 for (i = 0; i < 16; i++, mask >>= 1)
720 cache->saved_regs[i + M68K_FP0_REGNUM] = offset;
729 else if ((op & 0177760) == P_MOVEL_SP)
731 /* move.l %R,-(%sp) */
733 cache->saved_regs[regno] = offset;
737 else if (op == P_MOVEML_SP)
739 /* movem.l REGS,-(%sp) */
740 mask = read_memory_unsigned_integer (pc + 2, 2);
741 for (i = 0; i < 16; i++, mask >>= 1)
745 cache->saved_regs[15 - i] = offset;
760 /* Do a full analysis of the prologue at PC and update CACHE
761 accordingly. Bail out early if CURRENT_PC is reached. Return the
762 address where the analysis stopped.
764 We handle all cases that can be generated by gcc.
766 For allocating a stack frame:
770 pea (%fp); move.l %sp,%fp
771 link.w %a6,#0; add.l #-N,%sp
774 subq.w #8,%sp; subq.w #N-8,%sp
779 For saving registers:
783 move.l R1,-(%sp); move.l R2,-(%sp)
786 For setting up the PIC register:
793 m68k_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR pc,
794 CORE_ADDR current_pc, struct m68k_frame_cache *cache)
798 pc = m68k_analyze_frame_setup (pc, current_pc, cache);
799 pc = m68k_analyze_register_saves (gdbarch, pc, current_pc, cache);
800 if (pc >= current_pc)
803 /* Check for GOT setup. */
804 op = read_memory_unsigned_integer (pc, 4);
805 if (op == P_LEA_PC_A5)
807 /* lea (%pc,N),%a5 */
814 /* Return PC of first real instruction. */
817 m68k_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
819 struct m68k_frame_cache cache;
824 pc = m68k_analyze_prologue (gdbarch, start_pc, (CORE_ADDR) -1, &cache);
825 if (cache.locals < 0)
831 m68k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
835 frame_unwind_register (next_frame, gdbarch_pc_regnum (gdbarch), buf);
836 return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
841 static struct m68k_frame_cache *
842 m68k_frame_cache (struct frame_info *this_frame, void **this_cache)
844 struct m68k_frame_cache *cache;
851 cache = m68k_alloc_frame_cache ();
854 /* In principle, for normal frames, %fp holds the frame pointer,
855 which holds the base address for the current stack frame.
856 However, for functions that don't need it, the frame pointer is
857 optional. For these "frameless" functions the frame pointer is
858 actually the frame pointer of the calling frame. Signal
859 trampolines are just a special case of a "frameless" function.
860 They (usually) share their frame pointer with the frame that was
861 in progress when the signal occurred. */
863 get_frame_register (this_frame, M68K_FP_REGNUM, buf);
864 cache->base = extract_unsigned_integer (buf, 4);
865 if (cache->base == 0)
868 /* For normal frames, %pc is stored at 4(%fp). */
869 cache->saved_regs[M68K_PC_REGNUM] = 4;
871 cache->pc = get_frame_func (this_frame);
873 m68k_analyze_prologue (get_frame_arch (this_frame), cache->pc,
874 get_frame_pc (this_frame), cache);
876 if (cache->locals < 0)
878 /* We didn't find a valid frame, which means that CACHE->base
879 currently holds the frame pointer for our calling frame. If
880 we're at the start of a function, or somewhere half-way its
881 prologue, the function's frame probably hasn't been fully
882 setup yet. Try to reconstruct the base address for the stack
883 frame by looking at the stack pointer. For truly "frameless"
884 functions this might work too. */
886 get_frame_register (this_frame, M68K_SP_REGNUM, buf);
887 cache->base = extract_unsigned_integer (buf, 4) + cache->sp_offset;
890 /* Now that we have the base address for the stack frame we can
891 calculate the value of %sp in the calling frame. */
892 cache->saved_sp = cache->base + 8;
894 /* Adjust all the saved registers such that they contain addresses
895 instead of offsets. */
896 for (i = 0; i < M68K_NUM_REGS; i++)
897 if (cache->saved_regs[i] != -1)
898 cache->saved_regs[i] += cache->base;
904 m68k_frame_this_id (struct frame_info *this_frame, void **this_cache,
905 struct frame_id *this_id)
907 struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache);
909 /* This marks the outermost frame. */
910 if (cache->base == 0)
913 /* See the end of m68k_push_dummy_call. */
914 *this_id = frame_id_build (cache->base + 8, cache->pc);
917 static struct value *
918 m68k_frame_prev_register (struct frame_info *this_frame, void **this_cache,
921 struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache);
923 gdb_assert (regnum >= 0);
925 if (regnum == M68K_SP_REGNUM && cache->saved_sp)
926 return frame_unwind_got_constant (this_frame, regnum, cache->saved_sp);
928 if (regnum < M68K_NUM_REGS && cache->saved_regs[regnum] != -1)
929 return frame_unwind_got_memory (this_frame, regnum,
930 cache->saved_regs[regnum]);
932 return frame_unwind_got_register (this_frame, regnum, regnum);
935 static const struct frame_unwind m68k_frame_unwind =
939 m68k_frame_prev_register,
941 default_frame_sniffer
945 m68k_frame_base_address (struct frame_info *this_frame, void **this_cache)
947 struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache);
952 static const struct frame_base m68k_frame_base =
955 m68k_frame_base_address,
956 m68k_frame_base_address,
957 m68k_frame_base_address
960 static struct frame_id
961 m68k_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
965 fp = get_frame_register_unsigned (this_frame, M68K_FP_REGNUM);
967 /* See the end of m68k_push_dummy_call. */
968 return frame_id_build (fp + 8, get_frame_pc (this_frame));
972 /* Figure out where the longjmp will land. Slurp the args out of the stack.
973 We expect the first arg to be a pointer to the jmp_buf structure from which
974 we extract the pc (JB_PC) that we will land at. The pc is copied into PC.
975 This routine returns true on success. */
978 m68k_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
981 CORE_ADDR sp, jb_addr;
982 struct gdbarch *gdbarch = get_frame_arch (frame);
983 struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (frame));
987 internal_error (__FILE__, __LINE__,
988 _("m68k_get_longjmp_target: not implemented"));
992 buf = alloca (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT);
993 sp = get_frame_register_unsigned (frame, gdbarch_sp_regnum (gdbarch));
995 if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */
996 buf, gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT))
999 jb_addr = extract_unsigned_integer (buf, gdbarch_ptr_bit (gdbarch)
1002 if (target_read_memory (jb_addr + tdep->jb_pc * tdep->jb_elt_size, buf,
1003 gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT))
1006 *pc = extract_unsigned_integer (buf, gdbarch_ptr_bit (gdbarch)
1012 /* System V Release 4 (SVR4). */
1015 m68k_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
1017 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
1019 /* SVR4 uses a different calling convention. */
1020 set_gdbarch_return_value (gdbarch, m68k_svr4_return_value);
1022 /* SVR4 uses %a0 instead of %a1. */
1023 tdep->struct_value_regnum = M68K_A0_REGNUM;
1027 /* Function: m68k_gdbarch_init
1028 Initializer function for the m68k gdbarch vector.
1029 Called by gdbarch. Sets up the gdbarch vector(s) for this target. */
1031 static struct gdbarch *
1032 m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
1034 struct gdbarch_tdep *tdep = NULL;
1035 struct gdbarch *gdbarch;
1036 struct gdbarch_list *best_arch;
1037 struct tdesc_arch_data *tdesc_data = NULL;
1039 enum m68k_flavour flavour = m68k_no_flavour;
1041 const struct floatformat **long_double_format = floatformats_m68881_ext;
1043 /* Check any target description for validity. */
1044 if (tdesc_has_registers (info.target_desc))
1046 const struct tdesc_feature *feature;
1049 feature = tdesc_find_feature (info.target_desc,
1050 "org.gnu.gdb.m68k.core");
1051 if (feature != NULL)
1055 if (feature == NULL)
1057 feature = tdesc_find_feature (info.target_desc,
1058 "org.gnu.gdb.coldfire.core");
1059 if (feature != NULL)
1060 flavour = m68k_coldfire_flavour;
1063 if (feature == NULL)
1065 feature = tdesc_find_feature (info.target_desc,
1066 "org.gnu.gdb.fido.core");
1067 if (feature != NULL)
1068 flavour = m68k_fido_flavour;
1071 if (feature == NULL)
1074 tdesc_data = tdesc_data_alloc ();
1077 for (i = 0; i <= M68K_PC_REGNUM; i++)
1078 valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
1079 m68k_register_names[i]);
1083 tdesc_data_cleanup (tdesc_data);
1087 feature = tdesc_find_feature (info.target_desc,
1088 "org.gnu.gdb.coldfire.fp");
1089 if (feature != NULL)
1092 for (i = M68K_FP0_REGNUM; i <= M68K_FPI_REGNUM; i++)
1093 valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
1094 m68k_register_names[i]);
1097 tdesc_data_cleanup (tdesc_data);
1105 /* The mechanism for returning floating values from function
1106 and the type of long double depend on whether we're
1107 on ColdFire or standard m68k. */
1109 if (info.bfd_arch_info && info.bfd_arch_info->mach != 0)
1111 const bfd_arch_info_type *coldfire_arch =
1112 bfd_lookup_arch (bfd_arch_m68k, bfd_mach_mcf_isa_a_nodiv);
1115 && ((*info.bfd_arch_info->compatible)
1116 (info.bfd_arch_info, coldfire_arch)))
1117 flavour = m68k_coldfire_flavour;
1120 /* If there is already a candidate, use it. */
1121 for (best_arch = gdbarch_list_lookup_by_info (arches, &info);
1123 best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
1125 if (flavour != gdbarch_tdep (best_arch->gdbarch)->flavour)
1128 if (has_fp != gdbarch_tdep (best_arch->gdbarch)->fpregs_present)
1134 tdep = xmalloc (sizeof (struct gdbarch_tdep));
1135 gdbarch = gdbarch_alloc (&info, tdep);
1136 tdep->fpregs_present = has_fp;
1137 tdep->flavour = flavour;
1139 if (flavour == m68k_coldfire_flavour || flavour == m68k_fido_flavour)
1140 long_double_format = floatformats_ieee_double;
1141 set_gdbarch_long_double_format (gdbarch, long_double_format);
1142 set_gdbarch_long_double_bit (gdbarch, long_double_format[0]->totalsize);
1144 set_gdbarch_skip_prologue (gdbarch, m68k_skip_prologue);
1145 set_gdbarch_breakpoint_from_pc (gdbarch, m68k_local_breakpoint_from_pc);
1147 /* Stack grows down. */
1148 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
1149 set_gdbarch_frame_align (gdbarch, m68k_frame_align);
1151 set_gdbarch_believe_pcc_promotion (gdbarch, 1);
1152 if (flavour == m68k_coldfire_flavour || flavour == m68k_fido_flavour)
1153 set_gdbarch_decr_pc_after_break (gdbarch, 2);
1155 set_gdbarch_frame_args_skip (gdbarch, 8);
1156 set_gdbarch_dwarf2_reg_to_regnum (gdbarch, m68k_dwarf_reg_to_regnum);
1158 set_gdbarch_register_type (gdbarch, m68k_register_type);
1159 set_gdbarch_register_name (gdbarch, m68k_register_name);
1160 set_gdbarch_num_regs (gdbarch, M68K_NUM_REGS);
1161 set_gdbarch_sp_regnum (gdbarch, M68K_SP_REGNUM);
1162 set_gdbarch_pc_regnum (gdbarch, M68K_PC_REGNUM);
1163 set_gdbarch_ps_regnum (gdbarch, M68K_PS_REGNUM);
1164 set_gdbarch_fp0_regnum (gdbarch, M68K_FP0_REGNUM);
1165 set_gdbarch_convert_register_p (gdbarch, m68k_convert_register_p);
1166 set_gdbarch_register_to_value (gdbarch, m68k_register_to_value);
1167 set_gdbarch_value_to_register (gdbarch, m68k_value_to_register);
1170 set_gdbarch_fp0_regnum (gdbarch, M68K_FP0_REGNUM);
1172 /* Try to figure out if the arch uses floating registers to return
1173 floating point values from functions. */
1176 /* On ColdFire, floating point values are returned in D0. */
1177 if (flavour == m68k_coldfire_flavour)
1178 tdep->float_return = 0;
1180 tdep->float_return = 1;
1184 /* No floating registers, so can't use them for returning values. */
1185 tdep->float_return = 0;
1188 /* Function call & return */
1189 set_gdbarch_push_dummy_call (gdbarch, m68k_push_dummy_call);
1190 set_gdbarch_return_value (gdbarch, m68k_return_value);
1194 set_gdbarch_print_insn (gdbarch, print_insn_m68k);
1196 #if defined JB_PC && defined JB_ELEMENT_SIZE
1197 tdep->jb_pc = JB_PC;
1198 tdep->jb_elt_size = JB_ELEMENT_SIZE;
1202 tdep->struct_value_regnum = M68K_A1_REGNUM;
1203 tdep->struct_return = reg_struct_return;
1205 /* Frame unwinder. */
1206 set_gdbarch_dummy_id (gdbarch, m68k_dummy_id);
1207 set_gdbarch_unwind_pc (gdbarch, m68k_unwind_pc);
1209 /* Hook in the DWARF CFI frame unwinder. */
1210 dwarf2_append_unwinders (gdbarch);
1212 frame_base_set_default (gdbarch, &m68k_frame_base);
1214 /* Hook in ABI-specific overrides, if they have been registered. */
1215 gdbarch_init_osabi (info, gdbarch);
1217 /* Now we have tuned the configuration, set a few final things,
1218 based on what the OS ABI has told us. */
1220 if (tdep->jb_pc >= 0)
1221 set_gdbarch_get_longjmp_target (gdbarch, m68k_get_longjmp_target);
1223 frame_unwind_append_unwinder (gdbarch, &m68k_frame_unwind);
1226 tdesc_use_registers (gdbarch, info.target_desc, tdesc_data);
1233 m68k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
1235 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
1241 extern initialize_file_ftype _initialize_m68k_tdep; /* -Wmissing-prototypes */
1244 _initialize_m68k_tdep (void)
1246 gdbarch_register (bfd_arch_m68k, m68k_gdbarch_init, m68k_dump_tdep);
1248 /* Initialize the m68k-specific register types. */