d3e8b944c60f23480f6ce047049c50257ade39b3
[deliverable/binutils-gdb.git] / gdb / arm-tdep.c
1 /* Common target dependent code for GDB on ARM systems.
2 Copyright 1988, 1989, 1991, 1992, 1993, 1995, 1996, 1998, 1999, 2000,
3 2001 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
21
22 #include "defs.h"
23 #include "frame.h"
24 #include "inferior.h"
25 #include "gdbcmd.h"
26 #include "gdbcore.h"
27 #include "symfile.h"
28 #include "gdb_string.h"
29 #include "coff/internal.h" /* Internal format of COFF symbols in BFD */
30 #include "dis-asm.h" /* For register flavors. */
31 #include <ctype.h> /* for isupper () */
32 #include "regcache.h"
33 #include "doublest.h"
34 #include "value.h"
35 #include "solib-svr4.h"
36
37 /* Each OS has a different mechanism for accessing the various
38 registers stored in the sigcontext structure.
39
40 SIGCONTEXT_REGISTER_ADDRESS should be defined to the name (or
41 function pointer) which may be used to determine the addresses
42 of the various saved registers in the sigcontext structure.
43
44 For the ARM target, there are three parameters to this function.
45 The first is the pc value of the frame under consideration, the
46 second the stack pointer of this frame, and the last is the
47 register number to fetch.
48
49 If the tm.h file does not define this macro, then it's assumed that
50 no mechanism is needed and we define SIGCONTEXT_REGISTER_ADDRESS to
51 be 0.
52
53 When it comes time to multi-arching this code, see the identically
54 named machinery in ia64-tdep.c for an example of how it could be
55 done. It should not be necessary to modify the code below where
56 this macro is used. */
57
58 #ifdef SIGCONTEXT_REGISTER_ADDRESS
59 #ifndef SIGCONTEXT_REGISTER_ADDRESS_P
60 #define SIGCONTEXT_REGISTER_ADDRESS_P() 1
61 #endif
62 #else
63 #define SIGCONTEXT_REGISTER_ADDRESS(SP,PC,REG) 0
64 #define SIGCONTEXT_REGISTER_ADDRESS_P() 0
65 #endif
66
67 extern void _initialize_arm_tdep (void);
68
69 /* Number of different reg name sets (options). */
70 static int num_flavor_options;
71
72 /* We have more registers than the disassembler as gdb can print the value
73 of special registers as well.
74 The general register names are overwritten by whatever is being used by
75 the disassembler at the moment. We also adjust the case of cpsr and fps. */
76
77 /* Initial value: Register names used in ARM's ISA documentation. */
78 static char * arm_register_name_strings[] =
79 {"r0", "r1", "r2", "r3", /* 0 1 2 3 */
80 "r4", "r5", "r6", "r7", /* 4 5 6 7 */
81 "r8", "r9", "r10", "r11", /* 8 9 10 11 */
82 "r12", "sp", "lr", "pc", /* 12 13 14 15 */
83 "f0", "f1", "f2", "f3", /* 16 17 18 19 */
84 "f4", "f5", "f6", "f7", /* 20 21 22 23 */
85 "fps", "cpsr" }; /* 24 25 */
86 char **arm_register_names = arm_register_name_strings;
87
88 /* Valid register name flavors. */
89 static const char **valid_flavors;
90
91 /* Disassembly flavor to use. Default to "std" register names. */
92 static const char *disassembly_flavor;
93 static int current_option; /* Index to that option in the opcodes table. */
94
95 /* This is used to keep the bfd arch_info in sync with the disassembly
96 flavor. */
97 static void set_disassembly_flavor_sfunc(char *, int,
98 struct cmd_list_element *);
99 static void set_disassembly_flavor (void);
100
101 static void convert_from_extended (void *ptr, void *dbl);
102
103 /* Define other aspects of the stack frame. We keep the offsets of
104 all saved registers, 'cause we need 'em a lot! We also keep the
105 current size of the stack frame, and the offset of the frame
106 pointer from the stack pointer (for frameless functions, and when
107 we're still in the prologue of a function with a frame) */
108
109 struct frame_extra_info
110 {
111 struct frame_saved_regs fsr;
112 int framesize;
113 int frameoffset;
114 int framereg;
115 };
116
117 /* Addresses for calling Thumb functions have the bit 0 set.
118 Here are some macros to test, set, or clear bit 0 of addresses. */
119 #define IS_THUMB_ADDR(addr) ((addr) & 1)
120 #define MAKE_THUMB_ADDR(addr) ((addr) | 1)
121 #define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
122
123 /* Will a function return an aggregate type in memory or in a
124 register? Return 0 if an aggregate type can be returned in a
125 register, 1 if it must be returned in memory. */
126
127 int
128 arm_use_struct_convention (int gcc_p, struct type *type)
129 {
130 int nRc;
131 register enum type_code code;
132
133 /* In the ARM ABI, "integer" like aggregate types are returned in
134 registers. For an aggregate type to be integer like, its size
135 must be less than or equal to REGISTER_SIZE and the offset of
136 each addressable subfield must be zero. Note that bit fields are
137 not addressable, and all addressable subfields of unions always
138 start at offset zero.
139
140 This function is based on the behaviour of GCC 2.95.1.
141 See: gcc/arm.c: arm_return_in_memory() for details.
142
143 Note: All versions of GCC before GCC 2.95.2 do not set up the
144 parameters correctly for a function returning the following
145 structure: struct { float f;}; This should be returned in memory,
146 not a register. Richard Earnshaw sent me a patch, but I do not
147 know of any way to detect if a function like the above has been
148 compiled with the correct calling convention. */
149
150 /* All aggregate types that won't fit in a register must be returned
151 in memory. */
152 if (TYPE_LENGTH (type) > REGISTER_SIZE)
153 {
154 return 1;
155 }
156
157 /* The only aggregate types that can be returned in a register are
158 structs and unions. Arrays must be returned in memory. */
159 code = TYPE_CODE (type);
160 if ((TYPE_CODE_STRUCT != code) && (TYPE_CODE_UNION != code))
161 {
162 return 1;
163 }
164
165 /* Assume all other aggregate types can be returned in a register.
166 Run a check for structures, unions and arrays. */
167 nRc = 0;
168
169 if ((TYPE_CODE_STRUCT == code) || (TYPE_CODE_UNION == code))
170 {
171 int i;
172 /* Need to check if this struct/union is "integer" like. For
173 this to be true, its size must be less than or equal to
174 REGISTER_SIZE and the offset of each addressable subfield
175 must be zero. Note that bit fields are not addressable, and
176 unions always start at offset zero. If any of the subfields
177 is a floating point type, the struct/union cannot be an
178 integer type. */
179
180 /* For each field in the object, check:
181 1) Is it FP? --> yes, nRc = 1;
182 2) Is it addressable (bitpos != 0) and
183 not packed (bitsize == 0)?
184 --> yes, nRc = 1
185 */
186
187 for (i = 0; i < TYPE_NFIELDS (type); i++)
188 {
189 enum type_code field_type_code;
190 field_type_code = TYPE_CODE (TYPE_FIELD_TYPE (type, i));
191
192 /* Is it a floating point type field? */
193 if (field_type_code == TYPE_CODE_FLT)
194 {
195 nRc = 1;
196 break;
197 }
198
199 /* If bitpos != 0, then we have to care about it. */
200 if (TYPE_FIELD_BITPOS (type, i) != 0)
201 {
202 /* Bitfields are not addressable. If the field bitsize is
203 zero, then the field is not packed. Hence it cannot be
204 a bitfield or any other packed type. */
205 if (TYPE_FIELD_BITSIZE (type, i) == 0)
206 {
207 nRc = 1;
208 break;
209 }
210 }
211 }
212 }
213
214 return nRc;
215 }
216
217 int
218 arm_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
219 {
220 return (chain != 0 && (FRAME_SAVED_PC (thisframe) >= LOWEST_PC));
221 }
222
223 /* Set to true if the 32-bit mode is in use. */
224
225 int arm_apcs_32 = 1;
226
227 /* Flag set by arm_fix_call_dummy that tells whether the target
228 function is a Thumb function. This flag is checked by
229 arm_push_arguments. FIXME: Change the PUSH_ARGUMENTS macro (and
230 its use in valops.c) to pass the function address as an additional
231 parameter. */
232
233 static int target_is_thumb;
234
235 /* Flag set by arm_fix_call_dummy that tells whether the calling
236 function is a Thumb function. This flag is checked by
237 arm_pc_is_thumb and arm_call_dummy_breakpoint_offset. */
238
239 static int caller_is_thumb;
240
241 /* Determine if the program counter specified in MEMADDR is in a Thumb
242 function. */
243
244 int
245 arm_pc_is_thumb (CORE_ADDR memaddr)
246 {
247 struct minimal_symbol *sym;
248
249 /* If bit 0 of the address is set, assume this is a Thumb address. */
250 if (IS_THUMB_ADDR (memaddr))
251 return 1;
252
253 /* Thumb functions have a "special" bit set in minimal symbols. */
254 sym = lookup_minimal_symbol_by_pc (memaddr);
255 if (sym)
256 {
257 return (MSYMBOL_IS_SPECIAL (sym));
258 }
259 else
260 {
261 return 0;
262 }
263 }
264
265 /* Determine if the program counter specified in MEMADDR is in a call
266 dummy being called from a Thumb function. */
267
268 int
269 arm_pc_is_thumb_dummy (CORE_ADDR memaddr)
270 {
271 CORE_ADDR sp = read_sp ();
272
273 /* FIXME: Until we switch for the new call dummy macros, this heuristic
274 is the best we can do. We are trying to determine if the pc is on
275 the stack, which (hopefully) will only happen in a call dummy.
276 We hope the current stack pointer is not so far alway from the dummy
277 frame location (true if we have not pushed large data structures or
278 gone too many levels deep) and that our 1024 is not enough to consider
279 code regions as part of the stack (true for most practical purposes) */
280 if (PC_IN_CALL_DUMMY (memaddr, sp, sp + 1024))
281 return caller_is_thumb;
282 else
283 return 0;
284 }
285
286 CORE_ADDR
287 arm_addr_bits_remove (CORE_ADDR val)
288 {
289 if (arm_pc_is_thumb (val))
290 return (val & (arm_apcs_32 ? 0xfffffffe : 0x03fffffe));
291 else
292 return (val & (arm_apcs_32 ? 0xfffffffc : 0x03fffffc));
293 }
294
295 CORE_ADDR
296 arm_saved_pc_after_call (struct frame_info *frame)
297 {
298 return ADDR_BITS_REMOVE (read_register (LR_REGNUM));
299 }
300
301 int
302 arm_frameless_function_invocation (struct frame_info *fi)
303 {
304 CORE_ADDR func_start, after_prologue;
305 int frameless;
306
307 func_start = (get_pc_function_start ((fi)->pc) + FUNCTION_START_OFFSET);
308 after_prologue = SKIP_PROLOGUE (func_start);
309
310 /* There are some frameless functions whose first two instructions
311 follow the standard APCS form, in which case after_prologue will
312 be func_start + 8. */
313
314 frameless = (after_prologue < func_start + 12);
315 return frameless;
316 }
317
318 /* A typical Thumb prologue looks like this:
319 push {r7, lr}
320 add sp, sp, #-28
321 add r7, sp, #12
322 Sometimes the latter instruction may be replaced by:
323 mov r7, sp
324
325 or like this:
326 push {r7, lr}
327 mov r7, sp
328 sub sp, #12
329
330 or, on tpcs, like this:
331 sub sp,#16
332 push {r7, lr}
333 (many instructions)
334 mov r7, sp
335 sub sp, #12
336
337 There is always one instruction of three classes:
338 1 - push
339 2 - setting of r7
340 3 - adjusting of sp
341
342 When we have found at least one of each class we are done with the prolog.
343 Note that the "sub sp, #NN" before the push does not count.
344 */
345
346 static CORE_ADDR
347 thumb_skip_prologue (CORE_ADDR pc, CORE_ADDR func_end)
348 {
349 CORE_ADDR current_pc;
350 int findmask = 0; /* findmask:
351 bit 0 - push { rlist }
352 bit 1 - mov r7, sp OR add r7, sp, #imm (setting of r7)
353 bit 2 - sub sp, #simm OR add sp, #simm (adjusting of sp)
354 */
355
356 for (current_pc = pc; current_pc + 2 < func_end && current_pc < pc + 40; current_pc += 2)
357 {
358 unsigned short insn = read_memory_unsigned_integer (current_pc, 2);
359
360 if ((insn & 0xfe00) == 0xb400) /* push { rlist } */
361 {
362 findmask |= 1; /* push found */
363 }
364 else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR sub sp, #simm */
365 {
366 if ((findmask & 1) == 0) /* before push ? */
367 continue;
368 else
369 findmask |= 4; /* add/sub sp found */
370 }
371 else if ((insn & 0xff00) == 0xaf00) /* add r7, sp, #imm */
372 {
373 findmask |= 2; /* setting of r7 found */
374 }
375 else if (insn == 0x466f) /* mov r7, sp */
376 {
377 findmask |= 2; /* setting of r7 found */
378 }
379 else
380 continue; /* something in the prolog that we don't care about or some
381 instruction from outside the prolog scheduled here for optimization */
382 }
383
384 return current_pc;
385 }
386
387 /* The APCS (ARM Procedure Call Standard) defines the following
388 prologue:
389
390 mov ip, sp
391 [stmfd sp!, {a1,a2,a3,a4}]
392 stmfd sp!, {...,fp,ip,lr,pc}
393 [stfe f7, [sp, #-12]!]
394 [stfe f6, [sp, #-12]!]
395 [stfe f5, [sp, #-12]!]
396 [stfe f4, [sp, #-12]!]
397 sub fp, ip, #nn @@ nn == 20 or 4 depending on second insn */
398
399 CORE_ADDR
400 arm_skip_prologue (CORE_ADDR pc)
401 {
402 unsigned long inst;
403 CORE_ADDR skip_pc;
404 CORE_ADDR func_addr, func_end;
405 char *func_name;
406 struct symtab_and_line sal;
407
408 /* See what the symbol table says. */
409
410 if (find_pc_partial_function (pc, &func_name, &func_addr, &func_end))
411 {
412 struct symbol *sym;
413
414 /* Found a function. */
415 sym = lookup_symbol (func_name, NULL, VAR_NAMESPACE, NULL, NULL);
416 if (sym && SYMBOL_LANGUAGE (sym) != language_asm)
417 {
418 /* Don't use this trick for assembly source files. */
419 sal = find_pc_line (func_addr, 0);
420 if ((sal.line != 0) && (sal.end < func_end))
421 return sal.end;
422 }
423 }
424
425 /* Check if this is Thumb code. */
426 if (arm_pc_is_thumb (pc))
427 return thumb_skip_prologue (pc, func_end);
428
429 /* Can't find the prologue end in the symbol table, try it the hard way
430 by disassembling the instructions. */
431 skip_pc = pc;
432 inst = read_memory_integer (skip_pc, 4);
433 if (inst != 0xe1a0c00d) /* mov ip, sp */
434 return pc;
435
436 skip_pc += 4;
437 inst = read_memory_integer (skip_pc, 4);
438 if ((inst & 0xfffffff0) == 0xe92d0000) /* stmfd sp!,{a1,a2,a3,a4} */
439 {
440 skip_pc += 4;
441 inst = read_memory_integer (skip_pc, 4);
442 }
443
444 if ((inst & 0xfffff800) != 0xe92dd800) /* stmfd sp!,{...,fp,ip,lr,pc} */
445 return pc;
446
447 skip_pc += 4;
448 inst = read_memory_integer (skip_pc, 4);
449
450 /* Any insns after this point may float into the code, if it makes
451 for better instruction scheduling, so we skip them only if we
452 find them, but still consdier the function to be frame-ful. */
453
454 /* We may have either one sfmfd instruction here, or several stfe
455 insns, depending on the version of floating point code we
456 support. */
457 if ((inst & 0xffbf0fff) == 0xec2d0200) /* sfmfd fn, <cnt>, [sp]! */
458 {
459 skip_pc += 4;
460 inst = read_memory_integer (skip_pc, 4);
461 }
462 else
463 {
464 while ((inst & 0xffff8fff) == 0xed6d0103) /* stfe fn, [sp, #-12]! */
465 {
466 skip_pc += 4;
467 inst = read_memory_integer (skip_pc, 4);
468 }
469 }
470
471 if ((inst & 0xfffff000) == 0xe24cb000) /* sub fp, ip, #nn */
472 skip_pc += 4;
473
474 return skip_pc;
475 }
476 /* *INDENT-OFF* */
477 /* Function: thumb_scan_prologue (helper function for arm_scan_prologue)
478 This function decodes a Thumb function prologue to determine:
479 1) the size of the stack frame
480 2) which registers are saved on it
481 3) the offsets of saved regs
482 4) the offset from the stack pointer to the frame pointer
483 This information is stored in the "extra" fields of the frame_info.
484
485 A typical Thumb function prologue would create this stack frame
486 (offsets relative to FP)
487 old SP -> 24 stack parameters
488 20 LR
489 16 R7
490 R7 -> 0 local variables (16 bytes)
491 SP -> -12 additional stack space (12 bytes)
492 The frame size would thus be 36 bytes, and the frame offset would be
493 12 bytes. The frame register is R7.
494
495 The comments for thumb_skip_prolog() describe the algorithm we use to detect
496 the end of the prolog */
497 /* *INDENT-ON* */
498
499 static void
500 thumb_scan_prologue (struct frame_info *fi)
501 {
502 CORE_ADDR prologue_start;
503 CORE_ADDR prologue_end;
504 CORE_ADDR current_pc;
505 int saved_reg[16]; /* which register has been copied to register n? */
506 int findmask = 0; /* findmask:
507 bit 0 - push { rlist }
508 bit 1 - mov r7, sp OR add r7, sp, #imm (setting of r7)
509 bit 2 - sub sp, #simm OR add sp, #simm (adjusting of sp)
510 */
511 int i;
512
513 if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end))
514 {
515 struct symtab_and_line sal = find_pc_line (prologue_start, 0);
516
517 if (sal.line == 0) /* no line info, use current PC */
518 prologue_end = fi->pc;
519 else if (sal.end < prologue_end) /* next line begins after fn end */
520 prologue_end = sal.end; /* (probably means no prologue) */
521 }
522 else
523 prologue_end = prologue_start + 40; /* We're in the boondocks: allow for */
524 /* 16 pushes, an add, and "mv fp,sp" */
525
526 prologue_end = min (prologue_end, fi->pc);
527
528 /* Initialize the saved register map. When register H is copied to
529 register L, we will put H in saved_reg[L]. */
530 for (i = 0; i < 16; i++)
531 saved_reg[i] = i;
532
533 /* Search the prologue looking for instructions that set up the
534 frame pointer, adjust the stack pointer, and save registers.
535 Do this until all basic prolog instructions are found. */
536
537 fi->framesize = 0;
538 for (current_pc = prologue_start;
539 (current_pc < prologue_end) && ((findmask & 7) != 7);
540 current_pc += 2)
541 {
542 unsigned short insn;
543 int regno;
544 int offset;
545
546 insn = read_memory_unsigned_integer (current_pc, 2);
547
548 if ((insn & 0xfe00) == 0xb400) /* push { rlist } */
549 {
550 int mask;
551 findmask |= 1; /* push found */
552 /* Bits 0-7 contain a mask for registers R0-R7. Bit 8 says
553 whether to save LR (R14). */
554 mask = (insn & 0xff) | ((insn & 0x100) << 6);
555
556 /* Calculate offsets of saved R0-R7 and LR. */
557 for (regno = LR_REGNUM; regno >= 0; regno--)
558 if (mask & (1 << regno))
559 {
560 fi->framesize += 4;
561 fi->fsr.regs[saved_reg[regno]] = -(fi->framesize);
562 saved_reg[regno] = regno; /* reset saved register map */
563 }
564 }
565 else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR sub sp, #simm */
566 {
567 if ((findmask & 1) == 0) /* before push ? */
568 continue;
569 else
570 findmask |= 4; /* add/sub sp found */
571
572 offset = (insn & 0x7f) << 2; /* get scaled offset */
573 if (insn & 0x80) /* is it signed? (==subtracting) */
574 {
575 fi->frameoffset += offset;
576 offset = -offset;
577 }
578 fi->framesize -= offset;
579 }
580 else if ((insn & 0xff00) == 0xaf00) /* add r7, sp, #imm */
581 {
582 findmask |= 2; /* setting of r7 found */
583 fi->framereg = THUMB_FP_REGNUM;
584 fi->frameoffset = (insn & 0xff) << 2; /* get scaled offset */
585 }
586 else if (insn == 0x466f) /* mov r7, sp */
587 {
588 findmask |= 2; /* setting of r7 found */
589 fi->framereg = THUMB_FP_REGNUM;
590 fi->frameoffset = 0;
591 saved_reg[THUMB_FP_REGNUM] = SP_REGNUM;
592 }
593 else if ((insn & 0xffc0) == 0x4640) /* mov r0-r7, r8-r15 */
594 {
595 int lo_reg = insn & 7; /* dest. register (r0-r7) */
596 int hi_reg = ((insn >> 3) & 7) + 8; /* source register (r8-15) */
597 saved_reg[lo_reg] = hi_reg; /* remember hi reg was saved */
598 }
599 else
600 continue; /* something in the prolog that we don't care about or some
601 instruction from outside the prolog scheduled here for optimization */
602 }
603 }
604
605 /* Check if prologue for this frame's PC has already been scanned. If
606 it has, copy the relevant information about that prologue and
607 return non-zero. Otherwise do not copy anything and return zero.
608
609 The information saved in the cache includes:
610 * the frame register number;
611 * the size of the stack frame;
612 * the offsets of saved regs (relative to the old SP); and
613 * the offset from the stack pointer to the frame pointer
614
615 The cache contains only one entry, since this is adequate for the
616 typical sequence of prologue scan requests we get. When performing
617 a backtrace, GDB will usually ask to scan the same function twice
618 in a row (once to get the frame chain, and once to fill in the
619 extra frame information). */
620
621 static struct frame_info prologue_cache;
622
623 static int
624 check_prologue_cache (struct frame_info *fi)
625 {
626 int i;
627
628 if (fi->pc == prologue_cache.pc)
629 {
630 fi->framereg = prologue_cache.framereg;
631 fi->framesize = prologue_cache.framesize;
632 fi->frameoffset = prologue_cache.frameoffset;
633 for (i = 0; i < NUM_REGS; i++)
634 fi->fsr.regs[i] = prologue_cache.fsr.regs[i];
635 return 1;
636 }
637 else
638 return 0;
639 }
640
641
642 /* Copy the prologue information from fi to the prologue cache. */
643
644 static void
645 save_prologue_cache (struct frame_info *fi)
646 {
647 int i;
648
649 prologue_cache.pc = fi->pc;
650 prologue_cache.framereg = fi->framereg;
651 prologue_cache.framesize = fi->framesize;
652 prologue_cache.frameoffset = fi->frameoffset;
653
654 for (i = 0; i < NUM_REGS; i++)
655 prologue_cache.fsr.regs[i] = fi->fsr.regs[i];
656 }
657
658
659 /* This function decodes an ARM function prologue to determine:
660 1) the size of the stack frame
661 2) which registers are saved on it
662 3) the offsets of saved regs
663 4) the offset from the stack pointer to the frame pointer
664 This information is stored in the "extra" fields of the frame_info.
665
666 There are two basic forms for the ARM prologue. The fixed argument
667 function call will look like:
668
669 mov ip, sp
670 stmfd sp!, {fp, ip, lr, pc}
671 sub fp, ip, #4
672 [sub sp, sp, #4]
673
674 Which would create this stack frame (offsets relative to FP):
675 IP -> 4 (caller's stack)
676 FP -> 0 PC (points to address of stmfd instruction + 8 in callee)
677 -4 LR (return address in caller)
678 -8 IP (copy of caller's SP)
679 -12 FP (caller's FP)
680 SP -> -28 Local variables
681
682 The frame size would thus be 32 bytes, and the frame offset would be
683 28 bytes. The stmfd call can also save any of the vN registers it
684 plans to use, which increases the frame size accordingly.
685
686 Note: The stored PC is 8 off of the STMFD instruction that stored it
687 because the ARM Store instructions always store PC + 8 when you read
688 the PC register.
689
690 A variable argument function call will look like:
691
692 mov ip, sp
693 stmfd sp!, {a1, a2, a3, a4}
694 stmfd sp!, {fp, ip, lr, pc}
695 sub fp, ip, #20
696
697 Which would create this stack frame (offsets relative to FP):
698 IP -> 20 (caller's stack)
699 16 A4
700 12 A3
701 8 A2
702 4 A1
703 FP -> 0 PC (points to address of stmfd instruction + 8 in callee)
704 -4 LR (return address in caller)
705 -8 IP (copy of caller's SP)
706 -12 FP (caller's FP)
707 SP -> -28 Local variables
708
709 The frame size would thus be 48 bytes, and the frame offset would be
710 28 bytes.
711
712 There is another potential complication, which is that the optimizer
713 will try to separate the store of fp in the "stmfd" instruction from
714 the "sub fp, ip, #NN" instruction. Almost anything can be there, so
715 we just key on the stmfd, and then scan for the "sub fp, ip, #NN"...
716
717 Also, note, the original version of the ARM toolchain claimed that there
718 should be an
719
720 instruction at the end of the prologue. I have never seen GCC produce
721 this, and the ARM docs don't mention it. We still test for it below in
722 case it happens...
723
724 */
725
726 static void
727 arm_scan_prologue (struct frame_info *fi)
728 {
729 int regno, sp_offset, fp_offset;
730 LONGEST return_value;
731 CORE_ADDR prologue_start, prologue_end, current_pc;
732
733 /* Check if this function is already in the cache of frame information. */
734 if (check_prologue_cache (fi))
735 return;
736
737 /* Assume there is no frame until proven otherwise. */
738 fi->framereg = SP_REGNUM;
739 fi->framesize = 0;
740 fi->frameoffset = 0;
741
742 /* Check for Thumb prologue. */
743 if (arm_pc_is_thumb (fi->pc))
744 {
745 thumb_scan_prologue (fi);
746 save_prologue_cache (fi);
747 return;
748 }
749
750 /* Find the function prologue. If we can't find the function in
751 the symbol table, peek in the stack frame to find the PC. */
752 if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end))
753 {
754 /* One way to find the end of the prologue (which works well
755 for unoptimized code) is to do the following:
756
757 struct symtab_and_line sal = find_pc_line (prologue_start, 0);
758
759 if (sal.line == 0)
760 prologue_end = fi->pc;
761 else if (sal.end < prologue_end)
762 prologue_end = sal.end;
763
764 This mechanism is very accurate so long as the optimizer
765 doesn't move any instructions from the function body into the
766 prologue. If this happens, sal.end will be the last
767 instruction in the first hunk of prologue code just before
768 the first instruction that the scheduler has moved from
769 the body to the prologue.
770
771 In order to make sure that we scan all of the prologue
772 instructions, we use a slightly less accurate mechanism which
773 may scan more than necessary. To help compensate for this
774 lack of accuracy, the prologue scanning loop below contains
775 several clauses which'll cause the loop to terminate early if
776 an implausible prologue instruction is encountered.
777
778 The expression
779
780 prologue_start + 64
781
782 is a suitable endpoint since it accounts for the largest
783 possible prologue plus up to five instructions inserted by
784 the scheduler. */
785
786 if (prologue_end > prologue_start + 64)
787 {
788 prologue_end = prologue_start + 64; /* See above. */
789 }
790 }
791 else
792 {
793 /* Get address of the stmfd in the prologue of the callee; the saved
794 PC is the address of the stmfd + 8. */
795 if (!safe_read_memory_integer (fi->frame, 4, &return_value))
796 return;
797 else
798 {
799 prologue_start = ADDR_BITS_REMOVE (return_value) - 8;
800 prologue_end = prologue_start + 64; /* See above. */
801 }
802 }
803
804 /* Now search the prologue looking for instructions that set up the
805 frame pointer, adjust the stack pointer, and save registers.
806
807 Be careful, however, and if it doesn't look like a prologue,
808 don't try to scan it. If, for instance, a frameless function
809 begins with stmfd sp!, then we will tell ourselves there is
810 a frame, which will confuse stack traceback, as well ad"finish"
811 and other operations that rely on a knowledge of the stack
812 traceback.
813
814 In the APCS, the prologue should start with "mov ip, sp" so
815 if we don't see this as the first insn, we will stop. */
816
817 sp_offset = fp_offset = 0;
818
819 if (read_memory_unsigned_integer (prologue_start, 4)
820 == 0xe1a0c00d) /* mov ip, sp */
821 {
822 for (current_pc = prologue_start + 4; current_pc < prologue_end;
823 current_pc += 4)
824 {
825 unsigned int insn = read_memory_unsigned_integer (current_pc, 4);
826
827 if ((insn & 0xffff0000) == 0xe92d0000)
828 /* stmfd sp!, {..., fp, ip, lr, pc}
829 or
830 stmfd sp!, {a1, a2, a3, a4} */
831 {
832 int mask = insn & 0xffff;
833
834 /* Calculate offsets of saved registers. */
835 for (regno = PC_REGNUM; regno >= 0; regno--)
836 if (mask & (1 << regno))
837 {
838 sp_offset -= 4;
839 fi->fsr.regs[regno] = sp_offset;
840 }
841 }
842 else if ((insn & 0xfffff000) == 0xe24cb000) /* sub fp, ip #n */
843 {
844 unsigned imm = insn & 0xff; /* immediate value */
845 unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
846 imm = (imm >> rot) | (imm << (32 - rot));
847 fp_offset = -imm;
848 fi->framereg = FP_REGNUM;
849 }
850 else if ((insn & 0xfffff000) == 0xe24dd000) /* sub sp, sp #n */
851 {
852 unsigned imm = insn & 0xff; /* immediate value */
853 unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
854 imm = (imm >> rot) | (imm << (32 - rot));
855 sp_offset -= imm;
856 }
857 else if ((insn & 0xffff7fff) == 0xed6d0103) /* stfe f?, [sp, -#c]! */
858 {
859 sp_offset -= 12;
860 regno = F0_REGNUM + ((insn >> 12) & 0x07);
861 fi->fsr.regs[regno] = sp_offset;
862 }
863 else if ((insn & 0xffbf0fff) == 0xec2d0200) /* sfmfd f0, 4, [sp!] */
864 {
865 int n_saved_fp_regs;
866 unsigned int fp_start_reg, fp_bound_reg;
867
868 if ((insn & 0x800) == 0x800) /* N0 is set */
869 {
870 if ((insn & 0x40000) == 0x40000) /* N1 is set */
871 n_saved_fp_regs = 3;
872 else
873 n_saved_fp_regs = 1;
874 }
875 else
876 {
877 if ((insn & 0x40000) == 0x40000) /* N1 is set */
878 n_saved_fp_regs = 2;
879 else
880 n_saved_fp_regs = 4;
881 }
882
883 fp_start_reg = F0_REGNUM + ((insn >> 12) & 0x7);
884 fp_bound_reg = fp_start_reg + n_saved_fp_regs;
885 for (; fp_start_reg < fp_bound_reg; fp_start_reg++)
886 {
887 sp_offset -= 12;
888 fi->fsr.regs[fp_start_reg++] = sp_offset;
889 }
890 }
891 else if ((insn & 0xf0000000) != 0xe0000000)
892 break; /* Condition not true, exit early */
893 else if ((insn & 0xfe200000) == 0xe8200000) /* ldm? */
894 break; /* Don't scan past a block load */
895 else
896 /* The optimizer might shove anything into the prologue,
897 so we just skip what we don't recognize. */
898 continue;
899 }
900 }
901
902 /* The frame size is just the negative of the offset (from the original SP)
903 of the last thing thing we pushed on the stack. The frame offset is
904 [new FP] - [new SP]. */
905 fi->framesize = -sp_offset;
906 fi->frameoffset = fp_offset - sp_offset;
907
908 save_prologue_cache (fi);
909 }
910
911 /* Find REGNUM on the stack. Otherwise, it's in an active register.
912 One thing we might want to do here is to check REGNUM against the
913 clobber mask, and somehow flag it as invalid if it isn't saved on
914 the stack somewhere. This would provide a graceful failure mode
915 when trying to get the value of caller-saves registers for an inner
916 frame. */
917
918 static CORE_ADDR
919 arm_find_callers_reg (struct frame_info *fi, int regnum)
920 {
921 for (; fi; fi = fi->next)
922
923 #if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
924 if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
925 return generic_read_register_dummy (fi->pc, fi->frame, regnum);
926 else
927 #endif
928 if (fi->fsr.regs[regnum] != 0)
929 return read_memory_integer (fi->fsr.regs[regnum],
930 REGISTER_RAW_SIZE (regnum));
931 return read_register (regnum);
932 }
933 /* *INDENT-OFF* */
934 /* Function: frame_chain
935 Given a GDB frame, determine the address of the calling function's frame.
936 This will be used to create a new GDB frame struct, and then
937 INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
938 For ARM, we save the frame size when we initialize the frame_info.
939
940 The original definition of this function was a macro in tm-arm.h:
941 { In the case of the ARM, the frame's nominal address is the FP value,
942 and 12 bytes before comes the saved previous FP value as a 4-byte word. }
943
944 #define FRAME_CHAIN(thisframe) \
945 ((thisframe)->pc >= LOWEST_PC ? \
946 read_memory_integer ((thisframe)->frame - 12, 4) :\
947 0)
948 */
949 /* *INDENT-ON* */
950
951 CORE_ADDR
952 arm_frame_chain (struct frame_info *fi)
953 {
954 #if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
955 CORE_ADDR fn_start, callers_pc, fp;
956
957 /* is this a dummy frame? */
958 if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
959 return fi->frame; /* dummy frame same as caller's frame */
960
961 /* is caller-of-this a dummy frame? */
962 callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */
963 fp = arm_find_callers_reg (fi, FP_REGNUM);
964 if (PC_IN_CALL_DUMMY (callers_pc, fp, fp))
965 return fp; /* dummy frame's frame may bear no relation to ours */
966
967 if (find_pc_partial_function (fi->pc, 0, &fn_start, 0))
968 if (fn_start == entry_point_address ())
969 return 0; /* in _start fn, don't chain further */
970 #endif
971 CORE_ADDR caller_pc, fn_start;
972 struct frame_info caller_fi;
973 int framereg = fi->framereg;
974
975 if (fi->pc < LOWEST_PC)
976 return 0;
977
978 /* If the caller is the startup code, we're at the end of the chain. */
979 caller_pc = FRAME_SAVED_PC (fi);
980 if (find_pc_partial_function (caller_pc, 0, &fn_start, 0))
981 if (fn_start == entry_point_address ())
982 return 0;
983
984 /* If the caller is Thumb and the caller is ARM, or vice versa,
985 the frame register of the caller is different from ours.
986 So we must scan the prologue of the caller to determine its
987 frame register number. */
988 if (arm_pc_is_thumb (caller_pc) != arm_pc_is_thumb (fi->pc))
989 {
990 memset (&caller_fi, 0, sizeof (caller_fi));
991 caller_fi.pc = caller_pc;
992 arm_scan_prologue (&caller_fi);
993 framereg = caller_fi.framereg;
994 }
995
996 /* If the caller used a frame register, return its value.
997 Otherwise, return the caller's stack pointer. */
998 if (framereg == FP_REGNUM || framereg == THUMB_FP_REGNUM)
999 return arm_find_callers_reg (fi, framereg);
1000 else
1001 return fi->frame + fi->framesize;
1002 }
1003
1004 /* This function actually figures out the frame address for a given pc
1005 and sp. This is tricky because we sometimes don't use an explicit
1006 frame pointer, and the previous stack pointer isn't necessarily
1007 recorded on the stack. The only reliable way to get this info is
1008 to examine the prologue. FROMLEAF is a little confusing, it means
1009 this is the next frame up the chain AFTER a frameless function. If
1010 this is true, then the frame value for this frame is still in the
1011 fp register. */
1012
1013 void
1014 arm_init_extra_frame_info (int fromleaf, struct frame_info *fi)
1015 {
1016 int reg;
1017
1018 if (fi->next)
1019 fi->pc = FRAME_SAVED_PC (fi->next);
1020
1021 memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
1022
1023 #if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
1024 if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
1025 {
1026 /* We need to setup fi->frame here because run_stack_dummy gets it wrong
1027 by assuming it's always FP. */
1028 fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM);
1029 fi->framesize = 0;
1030 fi->frameoffset = 0;
1031 return;
1032 }
1033 else
1034 #endif
1035
1036 /* Determine whether or not we're in a sigtramp frame.
1037 Unfortunately, it isn't sufficient to test
1038 fi->signal_handler_caller because this value is sometimes set
1039 after invoking INIT_EXTRA_FRAME_INFO. So we test *both*
1040 fi->signal_handler_caller and IN_SIGTRAMP to determine if we need
1041 to use the sigcontext addresses for the saved registers.
1042
1043 Note: If an ARM IN_SIGTRAMP method ever needs to compare against
1044 the name of the function, the code below will have to be changed
1045 to first fetch the name of the function and then pass this name
1046 to IN_SIGTRAMP. */
1047
1048 if (SIGCONTEXT_REGISTER_ADDRESS_P ()
1049 && (fi->signal_handler_caller || IN_SIGTRAMP (fi->pc, 0)))
1050 {
1051 CORE_ADDR sp;
1052
1053 if (!fi->next)
1054 sp = read_sp();
1055 else
1056 sp = fi->next->frame - fi->next->frameoffset + fi->next->framesize;
1057
1058 for (reg = 0; reg < NUM_REGS; reg++)
1059 fi->fsr.regs[reg] = SIGCONTEXT_REGISTER_ADDRESS (sp, fi->pc, reg);
1060
1061 /* FIXME: What about thumb mode? */
1062 fi->framereg = SP_REGNUM;
1063 fi->frame = read_memory_integer (fi->fsr.regs[fi->framereg], 4);
1064 fi->framesize = 0;
1065 fi->frameoffset = 0;
1066
1067 }
1068 else
1069 {
1070 arm_scan_prologue (fi);
1071
1072 if (!fi->next)
1073 /* this is the innermost frame? */
1074 fi->frame = read_register (fi->framereg);
1075 else if (fi->framereg == FP_REGNUM || fi->framereg == THUMB_FP_REGNUM)
1076 {
1077 /* not the innermost frame */
1078 /* If we have an FP, the callee saved it. */
1079 if (fi->next->fsr.regs[fi->framereg] != 0)
1080 fi->frame =
1081 read_memory_integer (fi->next->fsr.regs[fi->framereg], 4);
1082 else if (fromleaf)
1083 /* If we were called by a frameless fn. then our frame is
1084 still in the frame pointer register on the board... */
1085 fi->frame = read_fp ();
1086 }
1087
1088 /* Calculate actual addresses of saved registers using offsets
1089 determined by arm_scan_prologue. */
1090 for (reg = 0; reg < NUM_REGS; reg++)
1091 if (fi->fsr.regs[reg] != 0)
1092 fi->fsr.regs[reg] += fi->frame + fi->framesize - fi->frameoffset;
1093 }
1094 }
1095
1096
1097 /* Find the caller of this frame. We do this by seeing if LR_REGNUM
1098 is saved in the stack anywhere, otherwise we get it from the
1099 registers.
1100
1101 The old definition of this function was a macro:
1102 #define FRAME_SAVED_PC(FRAME) \
1103 ADDR_BITS_REMOVE (read_memory_integer ((FRAME)->frame - 4, 4)) */
1104
1105 CORE_ADDR
1106 arm_frame_saved_pc (struct frame_info *fi)
1107 {
1108 #if 0 /* FIXME: enable this code if we convert to new call dummy scheme. */
1109 if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
1110 return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM);
1111 else
1112 #endif
1113 {
1114 CORE_ADDR pc = arm_find_callers_reg (fi, LR_REGNUM);
1115 return IS_THUMB_ADDR (pc) ? UNMAKE_THUMB_ADDR (pc) : pc;
1116 }
1117 }
1118
1119 /* Return the frame address. On ARM, it is R11; on Thumb it is R7.
1120 Examine the Program Status Register to decide which state we're in. */
1121
1122 CORE_ADDR
1123 arm_target_read_fp (void)
1124 {
1125 if (read_register (PS_REGNUM) & 0x20) /* Bit 5 is Thumb state bit */
1126 return read_register (THUMB_FP_REGNUM); /* R7 if Thumb */
1127 else
1128 return read_register (FP_REGNUM); /* R11 if ARM */
1129 }
1130
1131 /* Calculate the frame offsets of the saved registers (ARM version). */
1132
1133 void
1134 arm_frame_find_saved_regs (struct frame_info *fi,
1135 struct frame_saved_regs *regaddr)
1136 {
1137 memcpy (regaddr, &fi->fsr, sizeof (struct frame_saved_regs));
1138 }
1139
1140 void
1141 arm_push_dummy_frame (void)
1142 {
1143 CORE_ADDR old_sp = read_register (SP_REGNUM);
1144 CORE_ADDR sp = old_sp;
1145 CORE_ADDR fp, prologue_start;
1146 int regnum;
1147
1148 /* Push the two dummy prologue instructions in reverse order,
1149 so that they'll be in the correct low-to-high order in memory. */
1150 /* sub fp, ip, #4 */
1151 sp = push_word (sp, 0xe24cb004);
1152 /* stmdb sp!, {r0-r10, fp, ip, lr, pc} */
1153 prologue_start = sp = push_word (sp, 0xe92ddfff);
1154
1155 /* Push a pointer to the dummy prologue + 12, because when stm
1156 instruction stores the PC, it stores the address of the stm
1157 instruction itself plus 12. */
1158 fp = sp = push_word (sp, prologue_start + 12);
1159 sp = push_word (sp, read_register (PC_REGNUM)); /* FIXME: was PS_REGNUM */
1160 sp = push_word (sp, old_sp);
1161 sp = push_word (sp, read_register (FP_REGNUM));
1162
1163 for (regnum = 10; regnum >= 0; regnum--)
1164 sp = push_word (sp, read_register (regnum));
1165
1166 write_register (FP_REGNUM, fp);
1167 write_register (THUMB_FP_REGNUM, fp);
1168 write_register (SP_REGNUM, sp);
1169 }
1170
1171 /* Fix up the call dummy, based on whether the processor is currently
1172 in Thumb or ARM mode, and whether the target function is Thumb or
1173 ARM. There are three different situations requiring three
1174 different dummies:
1175
1176 * ARM calling ARM: uses the call dummy in tm-arm.h, which has already
1177 been copied into the dummy parameter to this function.
1178 * ARM calling Thumb: uses the call dummy in tm-arm.h, but with the
1179 "mov pc,r4" instruction patched to be a "bx r4" instead.
1180 * Thumb calling anything: uses the Thumb dummy defined below, which
1181 works for calling both ARM and Thumb functions.
1182
1183 All three call dummies expect to receive the target function
1184 address in R4, with the low bit set if it's a Thumb function. */
1185
1186 void
1187 arm_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs,
1188 struct value **args, struct type *type, int gcc_p)
1189 {
1190 static short thumb_dummy[4] =
1191 {
1192 0xf000, 0xf801, /* bl label */
1193 0xdf18, /* swi 24 */
1194 0x4720, /* label: bx r4 */
1195 };
1196 static unsigned long arm_bx_r4 = 0xe12fff14; /* bx r4 instruction */
1197
1198 /* Set flag indicating whether the current PC is in a Thumb function. */
1199 caller_is_thumb = arm_pc_is_thumb (read_pc ());
1200
1201 /* If the target function is Thumb, set the low bit of the function
1202 address. And if the CPU is currently in ARM mode, patch the
1203 second instruction of call dummy to use a BX instruction to
1204 switch to Thumb mode. */
1205 target_is_thumb = arm_pc_is_thumb (fun);
1206 if (target_is_thumb)
1207 {
1208 fun |= 1;
1209 if (!caller_is_thumb)
1210 store_unsigned_integer (dummy + 4, sizeof (arm_bx_r4), arm_bx_r4);
1211 }
1212
1213 /* If the CPU is currently in Thumb mode, use the Thumb call dummy
1214 instead of the ARM one that's already been copied. This will
1215 work for both Thumb and ARM target functions. */
1216 if (caller_is_thumb)
1217 {
1218 int i;
1219 char *p = dummy;
1220 int len = sizeof (thumb_dummy) / sizeof (thumb_dummy[0]);
1221
1222 for (i = 0; i < len; i++)
1223 {
1224 store_unsigned_integer (p, sizeof (thumb_dummy[0]), thumb_dummy[i]);
1225 p += sizeof (thumb_dummy[0]);
1226 }
1227 }
1228
1229 /* Put the target address in r4; the call dummy will copy this to
1230 the PC. */
1231 write_register (4, fun);
1232 }
1233
1234 /* Return the offset in the call dummy of the instruction that needs
1235 to have a breakpoint placed on it. This is the offset of the 'swi
1236 24' instruction, which is no longer actually used, but simply acts
1237 as a place-holder now.
1238
1239 This implements the CALL_DUMMY_BREAK_OFFSET macro. */
1240
1241 int
1242 arm_call_dummy_breakpoint_offset (void)
1243 {
1244 if (caller_is_thumb)
1245 return 4;
1246 else
1247 return 8;
1248 }
1249
1250 /* Note: ScottB
1251
1252 This function does not support passing parameters using the FPA
1253 variant of the APCS. It passes any floating point arguments in the
1254 general registers and/or on the stack. */
1255
1256 CORE_ADDR
1257 arm_push_arguments (int nargs, struct value **args, CORE_ADDR sp,
1258 int struct_return, CORE_ADDR struct_addr)
1259 {
1260 char *fp;
1261 int argnum, argreg, nstack_size;
1262
1263 /* Walk through the list of args and determine how large a temporary
1264 stack is required. Need to take care here as structs may be
1265 passed on the stack, and we have to to push them. */
1266 nstack_size = -4 * REGISTER_SIZE; /* Some arguments go into A1-A4. */
1267 if (struct_return) /* The struct address goes in A1. */
1268 nstack_size += REGISTER_SIZE;
1269
1270 /* Walk through the arguments and add their size to nstack_size. */
1271 for (argnum = 0; argnum < nargs; argnum++)
1272 {
1273 int len;
1274 struct type *arg_type;
1275
1276 arg_type = check_typedef (VALUE_TYPE (args[argnum]));
1277 len = TYPE_LENGTH (arg_type);
1278
1279 /* ANSI C code passes float arguments as integers, K&R code
1280 passes float arguments as doubles. Correct for this here. */
1281 if (TYPE_CODE_FLT == TYPE_CODE (arg_type) && REGISTER_SIZE == len)
1282 nstack_size += FP_REGISTER_VIRTUAL_SIZE;
1283 else
1284 nstack_size += len;
1285 }
1286
1287 /* Allocate room on the stack, and initialize our stack frame
1288 pointer. */
1289 fp = NULL;
1290 if (nstack_size > 0)
1291 {
1292 sp -= nstack_size;
1293 fp = (char *) sp;
1294 }
1295
1296 /* Initialize the integer argument register pointer. */
1297 argreg = A1_REGNUM;
1298
1299 /* The struct_return pointer occupies the first parameter passing
1300 register. */
1301 if (struct_return)
1302 write_register (argreg++, struct_addr);
1303
1304 /* Process arguments from left to right. Store as many as allowed
1305 in the parameter passing registers (A1-A4), and save the rest on
1306 the temporary stack. */
1307 for (argnum = 0; argnum < nargs; argnum++)
1308 {
1309 int len;
1310 char *val;
1311 CORE_ADDR regval;
1312 enum type_code typecode;
1313 struct type *arg_type, *target_type;
1314
1315 arg_type = check_typedef (VALUE_TYPE (args[argnum]));
1316 target_type = TYPE_TARGET_TYPE (arg_type);
1317 len = TYPE_LENGTH (arg_type);
1318 typecode = TYPE_CODE (arg_type);
1319 val = (char *) VALUE_CONTENTS (args[argnum]);
1320
1321 /* ANSI C code passes float arguments as integers, K&R code
1322 passes float arguments as doubles. The .stabs record for
1323 for ANSI prototype floating point arguments records the
1324 type as FP_INTEGER, while a K&R style (no prototype)
1325 .stabs records the type as FP_FLOAT. In this latter case
1326 the compiler converts the float arguments to double before
1327 calling the function. */
1328 if (TYPE_CODE_FLT == typecode && REGISTER_SIZE == len)
1329 {
1330 DOUBLEST dblval;
1331 dblval = extract_floating (val, len);
1332 len = TARGET_DOUBLE_BIT / TARGET_CHAR_BIT;
1333 val = alloca (len);
1334 store_floating (val, len, dblval);
1335 }
1336 #if 1
1337 /* I don't know why this code was disable. The only logical use
1338 for a function pointer is to call that function, so setting
1339 the mode bit is perfectly fine. FN */
1340 /* If the argument is a pointer to a function, and it is a Thumb
1341 function, set the low bit of the pointer. */
1342 if (TYPE_CODE_PTR == typecode
1343 && NULL != target_type
1344 && TYPE_CODE_FUNC == TYPE_CODE (target_type))
1345 {
1346 CORE_ADDR regval = extract_address (val, len);
1347 if (arm_pc_is_thumb (regval))
1348 store_address (val, len, MAKE_THUMB_ADDR (regval));
1349 }
1350 #endif
1351 /* Copy the argument to general registers or the stack in
1352 register-sized pieces. Large arguments are split between
1353 registers and stack. */
1354 while (len > 0)
1355 {
1356 int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE;
1357
1358 if (argreg <= ARM_LAST_ARG_REGNUM)
1359 {
1360 /* It's an argument being passed in a general register. */
1361 regval = extract_address (val, partial_len);
1362 write_register (argreg++, regval);
1363 }
1364 else
1365 {
1366 /* Push the arguments onto the stack. */
1367 write_memory ((CORE_ADDR) fp, val, REGISTER_SIZE);
1368 fp += REGISTER_SIZE;
1369 }
1370
1371 len -= partial_len;
1372 val += partial_len;
1373 }
1374 }
1375
1376 /* Return adjusted stack pointer. */
1377 return sp;
1378 }
1379
1380 void
1381 arm_pop_frame (void)
1382 {
1383 int regnum;
1384 struct frame_info *frame = get_current_frame ();
1385
1386 if (!PC_IN_CALL_DUMMY(frame->pc, frame->frame, read_fp()))
1387 {
1388 CORE_ADDR old_SP;
1389
1390 old_SP = read_register (frame->framereg);
1391 for (regnum = 0; regnum < NUM_REGS; regnum++)
1392 if (frame->fsr.regs[regnum] != 0)
1393 write_register (regnum,
1394 read_memory_integer (frame->fsr.regs[regnum], 4));
1395
1396 write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
1397 write_register (SP_REGNUM, old_SP);
1398 }
1399 else
1400 {
1401 CORE_ADDR sp;
1402
1403 sp = read_register (FP_REGNUM);
1404 sp -= sizeof(CORE_ADDR); /* we don't care about this first word */
1405
1406 write_register (PC_REGNUM, read_memory_integer (sp, 4));
1407 sp -= sizeof(CORE_ADDR);
1408 write_register (SP_REGNUM, read_memory_integer (sp, 4));
1409 sp -= sizeof(CORE_ADDR);
1410 write_register (FP_REGNUM, read_memory_integer (sp, 4));
1411 sp -= sizeof(CORE_ADDR);
1412
1413 for (regnum = 10; regnum >= 0; regnum--)
1414 {
1415 write_register (regnum, read_memory_integer (sp, 4));
1416 sp -= sizeof(CORE_ADDR);
1417 }
1418 }
1419
1420 flush_cached_frames ();
1421 }
1422
1423 static void
1424 print_fpu_flags (int flags)
1425 {
1426 if (flags & (1 << 0))
1427 fputs ("IVO ", stdout);
1428 if (flags & (1 << 1))
1429 fputs ("DVZ ", stdout);
1430 if (flags & (1 << 2))
1431 fputs ("OFL ", stdout);
1432 if (flags & (1 << 3))
1433 fputs ("UFL ", stdout);
1434 if (flags & (1 << 4))
1435 fputs ("INX ", stdout);
1436 putchar ('\n');
1437 }
1438
1439 void
1440 arm_float_info (void)
1441 {
1442 register unsigned long status = read_register (FPS_REGNUM);
1443 int type;
1444
1445 type = (status >> 24) & 127;
1446 printf ("%s FPU type %d\n",
1447 (status & (1 << 31)) ? "Hardware" : "Software",
1448 type);
1449 fputs ("mask: ", stdout);
1450 print_fpu_flags (status >> 16);
1451 fputs ("flags: ", stdout);
1452 print_fpu_flags (status);
1453 }
1454
1455 struct type *
1456 arm_register_type (int regnum)
1457 {
1458 if (regnum >= F0_REGNUM && regnum < F0_REGNUM + NUM_FREGS)
1459 {
1460 if (TARGET_BYTE_ORDER == BIG_ENDIAN)
1461 return builtin_type_arm_ext_big;
1462 else
1463 return builtin_type_arm_ext_littlebyte_bigword;
1464 }
1465 else
1466 return builtin_type_int32;
1467 }
1468
1469 /* NOTE: cagney/2001-08-20: Both convert_from_extended() and
1470 convert_to_extended() use floatformat_arm_ext_littlebyte_bigword.
1471 It is thought that this is is the floating-point register format on
1472 little-endian systems. */
1473
1474 static void
1475 convert_from_extended (void *ptr, void *dbl)
1476 {
1477 DOUBLEST d;
1478 if (TARGET_BYTE_ORDER == BIG_ENDIAN)
1479 floatformat_to_doublest (&floatformat_arm_ext_big, ptr, &d);
1480 else
1481 floatformat_to_doublest (&floatformat_arm_ext_littlebyte_bigword,
1482 ptr, &d);
1483 floatformat_from_doublest (TARGET_DOUBLE_FORMAT, &d, dbl);
1484 }
1485
1486 void
1487 convert_to_extended (void *dbl, void *ptr)
1488 {
1489 DOUBLEST d;
1490 floatformat_to_doublest (TARGET_DOUBLE_FORMAT, ptr, &d);
1491 if (TARGET_BYTE_ORDER == BIG_ENDIAN)
1492 floatformat_from_doublest (&floatformat_arm_ext_big, &d, dbl);
1493 else
1494 floatformat_from_doublest (&floatformat_arm_ext_littlebyte_bigword,
1495 &d, dbl);
1496 }
1497
1498 static int
1499 condition_true (unsigned long cond, unsigned long status_reg)
1500 {
1501 if (cond == INST_AL || cond == INST_NV)
1502 return 1;
1503
1504 switch (cond)
1505 {
1506 case INST_EQ:
1507 return ((status_reg & FLAG_Z) != 0);
1508 case INST_NE:
1509 return ((status_reg & FLAG_Z) == 0);
1510 case INST_CS:
1511 return ((status_reg & FLAG_C) != 0);
1512 case INST_CC:
1513 return ((status_reg & FLAG_C) == 0);
1514 case INST_MI:
1515 return ((status_reg & FLAG_N) != 0);
1516 case INST_PL:
1517 return ((status_reg & FLAG_N) == 0);
1518 case INST_VS:
1519 return ((status_reg & FLAG_V) != 0);
1520 case INST_VC:
1521 return ((status_reg & FLAG_V) == 0);
1522 case INST_HI:
1523 return ((status_reg & (FLAG_C | FLAG_Z)) == FLAG_C);
1524 case INST_LS:
1525 return ((status_reg & (FLAG_C | FLAG_Z)) != FLAG_C);
1526 case INST_GE:
1527 return (((status_reg & FLAG_N) == 0) == ((status_reg & FLAG_V) == 0));
1528 case INST_LT:
1529 return (((status_reg & FLAG_N) == 0) != ((status_reg & FLAG_V) == 0));
1530 case INST_GT:
1531 return (((status_reg & FLAG_Z) == 0) &&
1532 (((status_reg & FLAG_N) == 0) == ((status_reg & FLAG_V) == 0)));
1533 case INST_LE:
1534 return (((status_reg & FLAG_Z) != 0) ||
1535 (((status_reg & FLAG_N) == 0) != ((status_reg & FLAG_V) == 0)));
1536 }
1537 return 1;
1538 }
1539
1540 /* Support routines for single stepping. Calculate the next PC value. */
1541 #define submask(x) ((1L << ((x) + 1)) - 1)
1542 #define bit(obj,st) (((obj) >> (st)) & 1)
1543 #define bits(obj,st,fn) (((obj) >> (st)) & submask ((fn) - (st)))
1544 #define sbits(obj,st,fn) \
1545 ((long) (bits(obj,st,fn) | ((long) bit(obj,fn) * ~ submask (fn - st))))
1546 #define BranchDest(addr,instr) \
1547 ((CORE_ADDR) (((long) (addr)) + 8 + (sbits (instr, 0, 23) << 2)))
1548 #define ARM_PC_32 1
1549
1550 static unsigned long
1551 shifted_reg_val (unsigned long inst, int carry, unsigned long pc_val,
1552 unsigned long status_reg)
1553 {
1554 unsigned long res, shift;
1555 int rm = bits (inst, 0, 3);
1556 unsigned long shifttype = bits (inst, 5, 6);
1557
1558 if (bit (inst, 4))
1559 {
1560 int rs = bits (inst, 8, 11);
1561 shift = (rs == 15 ? pc_val + 8 : read_register (rs)) & 0xFF;
1562 }
1563 else
1564 shift = bits (inst, 7, 11);
1565
1566 res = (rm == 15
1567 ? ((pc_val | (ARM_PC_32 ? 0 : status_reg))
1568 + (bit (inst, 4) ? 12 : 8))
1569 : read_register (rm));
1570
1571 switch (shifttype)
1572 {
1573 case 0: /* LSL */
1574 res = shift >= 32 ? 0 : res << shift;
1575 break;
1576
1577 case 1: /* LSR */
1578 res = shift >= 32 ? 0 : res >> shift;
1579 break;
1580
1581 case 2: /* ASR */
1582 if (shift >= 32)
1583 shift = 31;
1584 res = ((res & 0x80000000L)
1585 ? ~((~res) >> shift) : res >> shift);
1586 break;
1587
1588 case 3: /* ROR/RRX */
1589 shift &= 31;
1590 if (shift == 0)
1591 res = (res >> 1) | (carry ? 0x80000000L : 0);
1592 else
1593 res = (res >> shift) | (res << (32 - shift));
1594 break;
1595 }
1596
1597 return res & 0xffffffff;
1598 }
1599
1600 /* Return number of 1-bits in VAL. */
1601
1602 static int
1603 bitcount (unsigned long val)
1604 {
1605 int nbits;
1606 for (nbits = 0; val != 0; nbits++)
1607 val &= val - 1; /* delete rightmost 1-bit in val */
1608 return nbits;
1609 }
1610
1611 static CORE_ADDR
1612 thumb_get_next_pc (CORE_ADDR pc)
1613 {
1614 unsigned long pc_val = ((unsigned long) pc) + 4; /* PC after prefetch */
1615 unsigned short inst1 = read_memory_integer (pc, 2);
1616 CORE_ADDR nextpc = pc + 2; /* default is next instruction */
1617 unsigned long offset;
1618
1619 if ((inst1 & 0xff00) == 0xbd00) /* pop {rlist, pc} */
1620 {
1621 CORE_ADDR sp;
1622
1623 /* Fetch the saved PC from the stack. It's stored above
1624 all of the other registers. */
1625 offset = bitcount (bits (inst1, 0, 7)) * REGISTER_SIZE;
1626 sp = read_register (SP_REGNUM);
1627 nextpc = (CORE_ADDR) read_memory_integer (sp + offset, 4);
1628 nextpc = ADDR_BITS_REMOVE (nextpc);
1629 if (nextpc == pc)
1630 error ("Infinite loop detected");
1631 }
1632 else if ((inst1 & 0xf000) == 0xd000) /* conditional branch */
1633 {
1634 unsigned long status = read_register (PS_REGNUM);
1635 unsigned long cond = bits (inst1, 8, 11);
1636 if (cond != 0x0f && condition_true (cond, status)) /* 0x0f = SWI */
1637 nextpc = pc_val + (sbits (inst1, 0, 7) << 1);
1638 }
1639 else if ((inst1 & 0xf800) == 0xe000) /* unconditional branch */
1640 {
1641 nextpc = pc_val + (sbits (inst1, 0, 10) << 1);
1642 }
1643 else if ((inst1 & 0xf800) == 0xf000) /* long branch with link */
1644 {
1645 unsigned short inst2 = read_memory_integer (pc + 2, 2);
1646 offset = (sbits (inst1, 0, 10) << 12) + (bits (inst2, 0, 10) << 1);
1647 nextpc = pc_val + offset;
1648 }
1649
1650 return nextpc;
1651 }
1652
1653 CORE_ADDR
1654 arm_get_next_pc (CORE_ADDR pc)
1655 {
1656 unsigned long pc_val;
1657 unsigned long this_instr;
1658 unsigned long status;
1659 CORE_ADDR nextpc;
1660
1661 if (arm_pc_is_thumb (pc))
1662 return thumb_get_next_pc (pc);
1663
1664 pc_val = (unsigned long) pc;
1665 this_instr = read_memory_integer (pc, 4);
1666 status = read_register (PS_REGNUM);
1667 nextpc = (CORE_ADDR) (pc_val + 4); /* Default case */
1668
1669 if (condition_true (bits (this_instr, 28, 31), status))
1670 {
1671 switch (bits (this_instr, 24, 27))
1672 {
1673 case 0x0:
1674 case 0x1: /* data processing */
1675 case 0x2:
1676 case 0x3:
1677 {
1678 unsigned long operand1, operand2, result = 0;
1679 unsigned long rn;
1680 int c;
1681
1682 if (bits (this_instr, 12, 15) != 15)
1683 break;
1684
1685 if (bits (this_instr, 22, 25) == 0
1686 && bits (this_instr, 4, 7) == 9) /* multiply */
1687 error ("Illegal update to pc in instruction");
1688
1689 /* Multiply into PC */
1690 c = (status & FLAG_C) ? 1 : 0;
1691 rn = bits (this_instr, 16, 19);
1692 operand1 = (rn == 15) ? pc_val + 8 : read_register (rn);
1693
1694 if (bit (this_instr, 25))
1695 {
1696 unsigned long immval = bits (this_instr, 0, 7);
1697 unsigned long rotate = 2 * bits (this_instr, 8, 11);
1698 operand2 = ((immval >> rotate) | (immval << (32 - rotate)))
1699 & 0xffffffff;
1700 }
1701 else /* operand 2 is a shifted register */
1702 operand2 = shifted_reg_val (this_instr, c, pc_val, status);
1703
1704 switch (bits (this_instr, 21, 24))
1705 {
1706 case 0x0: /*and */
1707 result = operand1 & operand2;
1708 break;
1709
1710 case 0x1: /*eor */
1711 result = operand1 ^ operand2;
1712 break;
1713
1714 case 0x2: /*sub */
1715 result = operand1 - operand2;
1716 break;
1717
1718 case 0x3: /*rsb */
1719 result = operand2 - operand1;
1720 break;
1721
1722 case 0x4: /*add */
1723 result = operand1 + operand2;
1724 break;
1725
1726 case 0x5: /*adc */
1727 result = operand1 + operand2 + c;
1728 break;
1729
1730 case 0x6: /*sbc */
1731 result = operand1 - operand2 + c;
1732 break;
1733
1734 case 0x7: /*rsc */
1735 result = operand2 - operand1 + c;
1736 break;
1737
1738 case 0x8:
1739 case 0x9:
1740 case 0xa:
1741 case 0xb: /* tst, teq, cmp, cmn */
1742 result = (unsigned long) nextpc;
1743 break;
1744
1745 case 0xc: /*orr */
1746 result = operand1 | operand2;
1747 break;
1748
1749 case 0xd: /*mov */
1750 /* Always step into a function. */
1751 result = operand2;
1752 break;
1753
1754 case 0xe: /*bic */
1755 result = operand1 & ~operand2;
1756 break;
1757
1758 case 0xf: /*mvn */
1759 result = ~operand2;
1760 break;
1761 }
1762 nextpc = (CORE_ADDR) ADDR_BITS_REMOVE (result);
1763
1764 if (nextpc == pc)
1765 error ("Infinite loop detected");
1766 break;
1767 }
1768
1769 case 0x4:
1770 case 0x5: /* data transfer */
1771 case 0x6:
1772 case 0x7:
1773 if (bit (this_instr, 20))
1774 {
1775 /* load */
1776 if (bits (this_instr, 12, 15) == 15)
1777 {
1778 /* rd == pc */
1779 unsigned long rn;
1780 unsigned long base;
1781
1782 if (bit (this_instr, 22))
1783 error ("Illegal update to pc in instruction");
1784
1785 /* byte write to PC */
1786 rn = bits (this_instr, 16, 19);
1787 base = (rn == 15) ? pc_val + 8 : read_register (rn);
1788 if (bit (this_instr, 24))
1789 {
1790 /* pre-indexed */
1791 int c = (status & FLAG_C) ? 1 : 0;
1792 unsigned long offset =
1793 (bit (this_instr, 25)
1794 ? shifted_reg_val (this_instr, c, pc_val, status)
1795 : bits (this_instr, 0, 11));
1796
1797 if (bit (this_instr, 23))
1798 base += offset;
1799 else
1800 base -= offset;
1801 }
1802 nextpc = (CORE_ADDR) read_memory_integer ((CORE_ADDR) base,
1803 4);
1804
1805 nextpc = ADDR_BITS_REMOVE (nextpc);
1806
1807 if (nextpc == pc)
1808 error ("Infinite loop detected");
1809 }
1810 }
1811 break;
1812
1813 case 0x8:
1814 case 0x9: /* block transfer */
1815 if (bit (this_instr, 20))
1816 {
1817 /* LDM */
1818 if (bit (this_instr, 15))
1819 {
1820 /* loading pc */
1821 int offset = 0;
1822
1823 if (bit (this_instr, 23))
1824 {
1825 /* up */
1826 unsigned long reglist = bits (this_instr, 0, 14);
1827 offset = bitcount (reglist) * 4;
1828 if (bit (this_instr, 24)) /* pre */
1829 offset += 4;
1830 }
1831 else if (bit (this_instr, 24))
1832 offset = -4;
1833
1834 {
1835 unsigned long rn_val =
1836 read_register (bits (this_instr, 16, 19));
1837 nextpc =
1838 (CORE_ADDR) read_memory_integer ((CORE_ADDR) (rn_val
1839 + offset),
1840 4);
1841 }
1842 nextpc = ADDR_BITS_REMOVE (nextpc);
1843 if (nextpc == pc)
1844 error ("Infinite loop detected");
1845 }
1846 }
1847 break;
1848
1849 case 0xb: /* branch & link */
1850 case 0xa: /* branch */
1851 {
1852 nextpc = BranchDest (pc, this_instr);
1853
1854 nextpc = ADDR_BITS_REMOVE (nextpc);
1855 if (nextpc == pc)
1856 error ("Infinite loop detected");
1857 break;
1858 }
1859
1860 case 0xc:
1861 case 0xd:
1862 case 0xe: /* coproc ops */
1863 case 0xf: /* SWI */
1864 break;
1865
1866 default:
1867 fprintf (stderr, "Bad bit-field extraction\n");
1868 return (pc);
1869 }
1870 }
1871
1872 return nextpc;
1873 }
1874
1875 /* single_step() is called just before we want to resume the inferior,
1876 if we want to single-step it but there is no hardware or kernel
1877 single-step support. We find the target of the coming instruction
1878 and breakpoint it.
1879
1880 single_step is also called just after the inferior stops. If we had
1881 set up a simulated single-step, we undo our damage. */
1882
1883 void
1884 arm_software_single_step (ignore, insert_bpt)
1885 int ignore; /* Signal, not needed */
1886 int insert_bpt;
1887 {
1888 static int next_pc; /* State between setting and unsetting. */
1889 static char break_mem[BREAKPOINT_MAX]; /* Temporary storage for mem@bpt */
1890
1891 if (insert_bpt)
1892 {
1893 next_pc = arm_get_next_pc (read_register (PC_REGNUM));
1894 target_insert_breakpoint (next_pc, break_mem);
1895 }
1896 else
1897 target_remove_breakpoint (next_pc, break_mem);
1898 }
1899
1900 #include "bfd-in2.h"
1901 #include "libcoff.h"
1902
1903 static int
1904 gdb_print_insn_arm (bfd_vma memaddr, disassemble_info *info)
1905 {
1906 if (arm_pc_is_thumb (memaddr))
1907 {
1908 static asymbol *asym;
1909 static combined_entry_type ce;
1910 static struct coff_symbol_struct csym;
1911 static struct _bfd fake_bfd;
1912 static bfd_target fake_target;
1913
1914 if (csym.native == NULL)
1915 {
1916 /* Create a fake symbol vector containing a Thumb symbol. This is
1917 solely so that the code in print_insn_little_arm() and
1918 print_insn_big_arm() in opcodes/arm-dis.c will detect the presence
1919 of a Thumb symbol and switch to decoding Thumb instructions. */
1920
1921 fake_target.flavour = bfd_target_coff_flavour;
1922 fake_bfd.xvec = &fake_target;
1923 ce.u.syment.n_sclass = C_THUMBEXTFUNC;
1924 csym.native = &ce;
1925 csym.symbol.the_bfd = &fake_bfd;
1926 csym.symbol.name = "fake";
1927 asym = (asymbol *) & csym;
1928 }
1929
1930 memaddr = UNMAKE_THUMB_ADDR (memaddr);
1931 info->symbols = &asym;
1932 }
1933 else
1934 info->symbols = NULL;
1935
1936 if (TARGET_BYTE_ORDER == BIG_ENDIAN)
1937 return print_insn_big_arm (memaddr, info);
1938 else
1939 return print_insn_little_arm (memaddr, info);
1940 }
1941
1942 /* This function implements the BREAKPOINT_FROM_PC macro. It uses the
1943 program counter value to determine whether a 16-bit or 32-bit
1944 breakpoint should be used. It returns a pointer to a string of
1945 bytes that encode a breakpoint instruction, stores the length of
1946 the string to *lenptr, and adjusts the program counter (if
1947 necessary) to point to the actual memory location where the
1948 breakpoint should be inserted. */
1949
1950 unsigned char *
1951 arm_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
1952 {
1953 if (arm_pc_is_thumb (*pcptr) || arm_pc_is_thumb_dummy (*pcptr))
1954 {
1955 if (TARGET_BYTE_ORDER == BIG_ENDIAN)
1956 {
1957 static char thumb_breakpoint[] = THUMB_BE_BREAKPOINT;
1958 *pcptr = UNMAKE_THUMB_ADDR (*pcptr);
1959 *lenptr = sizeof (thumb_breakpoint);
1960 return thumb_breakpoint;
1961 }
1962 else
1963 {
1964 static char thumb_breakpoint[] = THUMB_LE_BREAKPOINT;
1965 *pcptr = UNMAKE_THUMB_ADDR (*pcptr);
1966 *lenptr = sizeof (thumb_breakpoint);
1967 return thumb_breakpoint;
1968 }
1969 }
1970 else
1971 {
1972 if (TARGET_BYTE_ORDER == BIG_ENDIAN)
1973 {
1974 static char arm_breakpoint[] = ARM_BE_BREAKPOINT;
1975 *lenptr = sizeof (arm_breakpoint);
1976 return arm_breakpoint;
1977 }
1978 else
1979 {
1980 static char arm_breakpoint[] = ARM_LE_BREAKPOINT;
1981 *lenptr = sizeof (arm_breakpoint);
1982 return arm_breakpoint;
1983 }
1984 }
1985 }
1986
1987 /* Extract from an array REGBUF containing the (raw) register state a
1988 function return value of type TYPE, and copy that, in virtual
1989 format, into VALBUF. */
1990
1991 void
1992 arm_extract_return_value (struct type *type,
1993 char regbuf[REGISTER_BYTES],
1994 char *valbuf)
1995 {
1996 if (TYPE_CODE_FLT == TYPE_CODE (type))
1997 convert_from_extended (&regbuf[REGISTER_BYTE (F0_REGNUM)], valbuf);
1998 else
1999 memcpy (valbuf, &regbuf[REGISTER_BYTE (A1_REGNUM)], TYPE_LENGTH (type));
2000 }
2001
2002 /* Return non-zero if the PC is inside a thumb call thunk. */
2003
2004 int
2005 arm_in_call_stub (CORE_ADDR pc, char *name)
2006 {
2007 CORE_ADDR start_addr;
2008
2009 /* Find the starting address of the function containing the PC. If
2010 the caller didn't give us a name, look it up at the same time. */
2011 if (find_pc_partial_function (pc, name ? NULL : &name, &start_addr, NULL) == 0)
2012 return 0;
2013
2014 return strncmp (name, "_call_via_r", 11) == 0;
2015 }
2016
2017 /* If PC is in a Thumb call or return stub, return the address of the
2018 target PC, which is in a register. The thunk functions are called
2019 _called_via_xx, where x is the register name. The possible names
2020 are r0-r9, sl, fp, ip, sp, and lr. */
2021
2022 CORE_ADDR
2023 arm_skip_stub (CORE_ADDR pc)
2024 {
2025 char *name;
2026 CORE_ADDR start_addr;
2027
2028 /* Find the starting address and name of the function containing the PC. */
2029 if (find_pc_partial_function (pc, &name, &start_addr, NULL) == 0)
2030 return 0;
2031
2032 /* Call thunks always start with "_call_via_". */
2033 if (strncmp (name, "_call_via_", 10) == 0)
2034 {
2035 /* Use the name suffix to determine which register contains the
2036 target PC. */
2037 static char *table[15] =
2038 {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
2039 "r8", "r9", "sl", "fp", "ip", "sp", "lr"
2040 };
2041 int regno;
2042
2043 for (regno = 0; regno <= 14; regno++)
2044 if (strcmp (&name[10], table[regno]) == 0)
2045 return read_register (regno);
2046 }
2047
2048 return 0; /* not a stub */
2049 }
2050
2051 /* If the user changes the register disassembly flavor used for info register
2052 and other commands, we have to also switch the flavor used in opcodes
2053 for disassembly output.
2054 This function is run in the set disassembly_flavor command, and does that. */
2055
2056 static void
2057 set_disassembly_flavor_sfunc (char *args, int from_tty,
2058 struct cmd_list_element *c)
2059 {
2060 set_disassembly_flavor ();
2061 }
2062 \f
2063 static void
2064 set_disassembly_flavor (void)
2065 {
2066 const char *setname, *setdesc, **regnames;
2067 int numregs, j;
2068
2069 /* Find the flavor that the user wants in the opcodes table. */
2070 int current = 0;
2071 numregs = get_arm_regnames (current, &setname, &setdesc, &regnames);
2072 while ((disassembly_flavor != setname)
2073 && (current < num_flavor_options))
2074 get_arm_regnames (++current, &setname, &setdesc, &regnames);
2075 current_option = current;
2076
2077 /* Fill our copy. */
2078 for (j = 0; j < numregs; j++)
2079 arm_register_names[j] = (char *) regnames[j];
2080
2081 /* Adjust case. */
2082 if (isupper (*regnames[PC_REGNUM]))
2083 {
2084 arm_register_names[FPS_REGNUM] = "FPS";
2085 arm_register_names[PS_REGNUM] = "CPSR";
2086 }
2087 else
2088 {
2089 arm_register_names[FPS_REGNUM] = "fps";
2090 arm_register_names[PS_REGNUM] = "cpsr";
2091 }
2092
2093 /* Synchronize the disassembler. */
2094 set_arm_regname_option (current);
2095 }
2096
2097 /* arm_othernames implements the "othernames" command. This is kind
2098 of hacky, and I prefer the set-show disassembly-flavor which is
2099 also used for the x86 gdb. I will keep this around, however, in
2100 case anyone is actually using it. */
2101
2102 static void
2103 arm_othernames (char *names, int n)
2104 {
2105 /* Circle through the various flavors. */
2106 current_option = (current_option + 1) % num_flavor_options;
2107
2108 disassembly_flavor = valid_flavors[current_option];
2109 set_disassembly_flavor ();
2110 }
2111
2112 /* Fetch, and possibly build, an appropriate link_map_offsets structure
2113 for ARM linux targets using the struct offsets defined in <link.h>.
2114 Note, however, that link.h is not actually referred to in this file.
2115 Instead, the relevant structs offsets were obtained from examining
2116 link.h. (We can't refer to link.h from this file because the host
2117 system won't necessarily have it, or if it does, the structs which
2118 it defines will refer to the host system, not the target.) */
2119
2120 struct link_map_offsets *
2121 arm_linux_svr4_fetch_link_map_offsets (void)
2122 {
2123 static struct link_map_offsets lmo;
2124 static struct link_map_offsets *lmp = 0;
2125
2126 if (lmp == 0)
2127 {
2128 lmp = &lmo;
2129
2130 lmo.r_debug_size = 8; /* Actual size is 20, but this is all we
2131 need. */
2132
2133 lmo.r_map_offset = 4;
2134 lmo.r_map_size = 4;
2135
2136 lmo.link_map_size = 20; /* Actual size is 552, but this is all we
2137 need. */
2138
2139 lmo.l_addr_offset = 0;
2140 lmo.l_addr_size = 4;
2141
2142 lmo.l_name_offset = 4;
2143 lmo.l_name_size = 4;
2144
2145 lmo.l_next_offset = 12;
2146 lmo.l_next_size = 4;
2147
2148 lmo.l_prev_offset = 16;
2149 lmo.l_prev_size = 4;
2150 }
2151
2152 return lmp;
2153 }
2154
2155 void
2156 _initialize_arm_tdep (void)
2157 {
2158 struct ui_file *stb;
2159 long length;
2160 struct cmd_list_element *new_cmd;
2161 const char *setname;
2162 const char *setdesc;
2163 const char **regnames;
2164 int numregs, i, j;
2165 static char *helptext;
2166
2167 tm_print_insn = gdb_print_insn_arm;
2168
2169 /* Get the number of possible sets of register names defined in opcodes. */
2170 num_flavor_options = get_arm_regname_num_options ();
2171
2172 /* Sync the opcode insn printer with our register viewer: */
2173 parse_arm_disassembler_option ("reg-names-std");
2174
2175 /* Begin creating the help text. */
2176 stb = mem_fileopen ();
2177 fprintf_unfiltered (stb, "Set the disassembly flavor.\n\
2178 The valid values are:\n");
2179
2180 /* Initialize the array that will be passed to add_set_enum_cmd(). */
2181 valid_flavors = xmalloc ((num_flavor_options + 1) * sizeof (char *));
2182 for (i = 0; i < num_flavor_options; i++)
2183 {
2184 numregs = get_arm_regnames (i, &setname, &setdesc, &regnames);
2185 valid_flavors[i] = setname;
2186 fprintf_unfiltered (stb, "%s - %s\n", setname,
2187 setdesc);
2188 /* Copy the default names (if found) and synchronize disassembler. */
2189 if (!strcmp (setname, "std"))
2190 {
2191 disassembly_flavor = setname;
2192 current_option = i;
2193 for (j = 0; j < numregs; j++)
2194 arm_register_names[j] = (char *) regnames[j];
2195 set_arm_regname_option (i);
2196 }
2197 }
2198 /* Mark the end of valid options. */
2199 valid_flavors[num_flavor_options] = NULL;
2200
2201 /* Finish the creation of the help text. */
2202 fprintf_unfiltered (stb, "The default is \"std\".");
2203 helptext = ui_file_xstrdup (stb, &length);
2204 ui_file_delete (stb);
2205
2206 /* Add the disassembly-flavor command */
2207 new_cmd = add_set_enum_cmd ("disassembly-flavor", no_class,
2208 valid_flavors,
2209 &disassembly_flavor,
2210 helptext,
2211 &setlist);
2212 new_cmd->function.sfunc = set_disassembly_flavor_sfunc;
2213 add_show_from_set (new_cmd, &showlist);
2214
2215 /* ??? Maybe this should be a boolean. */
2216 add_show_from_set (add_set_cmd ("apcs32", no_class,
2217 var_zinteger, (char *) &arm_apcs_32,
2218 "Set usage of ARM 32-bit mode.\n", &setlist),
2219 &showlist);
2220
2221 /* Add the deprecated "othernames" command */
2222
2223 add_com ("othernames", class_obscure, arm_othernames,
2224 "Switch to the next set of register names.");
2225 }
2226
2227 /* Test whether the coff symbol specific value corresponds to a Thumb
2228 function. */
2229
2230 int
2231 coff_sym_is_thumb (int val)
2232 {
2233 return (val == C_THUMBEXT ||
2234 val == C_THUMBSTAT ||
2235 val == C_THUMBEXTFUNC ||
2236 val == C_THUMBSTATFUNC ||
2237 val == C_THUMBLABEL);
2238 }
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