1 /* Target-dependent code for GDB, the GNU debugger.
2 Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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, Boston, MA 02111-1307, USA. */
29 #include "xcoffsolib.h"
31 extern struct obstack frame_cache_obstack
;
35 /* Breakpoint shadows for the single step instructions will be kept here. */
37 static struct sstep_breaks
{
38 /* Address, or 0 if this is not in use. */
40 /* Shadow contents. */
44 /* Hook for determining the TOC address when calling functions in the
45 inferior under AIX. The initialization code in rs6000-nat.c sets
46 this hook to point to find_toc_address. */
48 CORE_ADDR (*find_toc_address_hook
) PARAMS ((CORE_ADDR
)) = NULL
;
50 /* Static function prototypes */
52 static CORE_ADDR branch_dest
PARAMS ((int opcode
, int instr
, CORE_ADDR pc
,
55 static void frame_get_cache_fsr
PARAMS ((struct frame_info
*fi
,
56 struct rs6000_framedata
*fdatap
));
58 static void pop_dummy_frame
PARAMS ((void));
60 /* Calculate the destination of a branch/jump. Return -1 if not a branch. */
63 branch_dest (opcode
, instr
, pc
, safety
)
74 absolute
= (int) ((instr
>> 1) & 1);
78 immediate
= ((instr
& ~3) << 6) >> 6; /* br unconditional */
82 dest
= pc
+ immediate
;
86 immediate
= ((instr
& ~3) << 16) >> 16; /* br conditional */
90 dest
= pc
+ immediate
;
94 ext_op
= (instr
>>1) & 0x3ff;
96 if (ext_op
== 16) /* br conditional register */
98 dest
= read_register (LR_REGNUM
) & ~3;
100 /* If we are about to return from a signal handler, dest is
101 something like 0x3c90. The current frame is a signal handler
102 caller frame, upon completion of the sigreturn system call
103 execution will return to the saved PC in the frame. */
104 if (dest
< TEXT_SEGMENT_BASE
)
106 struct frame_info
*fi
;
108 fi
= get_current_frame ();
110 dest
= read_memory_integer (fi
->frame
+ SIG_FRAME_PC_OFFSET
,
115 else if (ext_op
== 528) /* br cond to count reg */
117 dest
= read_register (CTR_REGNUM
) & ~3;
119 /* If we are about to execute a system call, dest is something
120 like 0x22fc or 0x3b00. Upon completion the system call
121 will return to the address in the link register. */
122 if (dest
< TEXT_SEGMENT_BASE
)
123 dest
= read_register (LR_REGNUM
) & ~3;
130 return (dest
< TEXT_SEGMENT_BASE
) ? safety
: dest
;
134 /* Sequence of bytes for breakpoint instruction. */
136 #define BIG_BREAKPOINT { 0x7d, 0x82, 0x10, 0x08 }
137 #define LITTLE_BREAKPOINT { 0x08, 0x10, 0x82, 0x7d }
140 rs6000_breakpoint_from_pc (bp_addr
, bp_size
)
144 static unsigned char big_breakpoint
[] = BIG_BREAKPOINT
;
145 static unsigned char little_breakpoint
[] = LITTLE_BREAKPOINT
;
147 if (TARGET_BYTE_ORDER
== BIG_ENDIAN
)
148 return big_breakpoint
;
150 return little_breakpoint
;
154 /* AIX does not support PT_STEP. Simulate it. */
157 rs6000_software_single_step (signal
, insert_breakpoints_p
)
158 enum target_signal signal
;
159 int insert_breakpoints_p
;
161 #define INSNLEN(OPCODE) 4
163 static char le_breakp
[] = LITTLE_BREAKPOINT
;
164 static char be_breakp
[] = BIG_BREAKPOINT
;
165 char *breakp
= TARGET_BYTE_ORDER
== BIG_ENDIAN
? be_breakp
: le_breakp
;
171 if (insert_breakpoints_p
) {
175 insn
= read_memory_integer (loc
, 4);
177 breaks
[0] = loc
+ INSNLEN(insn
);
179 breaks
[1] = branch_dest (opcode
, insn
, loc
, breaks
[0]);
181 /* Don't put two breakpoints on the same address. */
182 if (breaks
[1] == breaks
[0])
185 stepBreaks
[1].address
= 0;
187 for (ii
=0; ii
< 2; ++ii
) {
189 /* ignore invalid breakpoint. */
190 if ( breaks
[ii
] == -1)
193 read_memory (breaks
[ii
], stepBreaks
[ii
].data
, 4);
195 write_memory (breaks
[ii
], breakp
, 4);
196 stepBreaks
[ii
].address
= breaks
[ii
];
201 /* remove step breakpoints. */
202 for (ii
=0; ii
< 2; ++ii
)
203 if (stepBreaks
[ii
].address
!= 0)
205 (stepBreaks
[ii
].address
, stepBreaks
[ii
].data
, 4);
208 errno
= 0; /* FIXME, don't ignore errors! */
209 /* What errors? {read,write}_memory call error(). */
213 /* return pc value after skipping a function prologue and also return
214 information about a function frame.
216 in struct rs6000_frameinfo fdata:
217 - frameless is TRUE, if function does not have a frame.
218 - nosavedpc is TRUE, if function does not save %pc value in its frame.
219 - offset is the number of bytes used in the frame to save registers.
220 - saved_gpr is the number of the first saved gpr.
221 - saved_fpr is the number of the first saved fpr.
222 - alloca_reg is the number of the register used for alloca() handling.
224 - gpr_offset is the offset of the saved gprs
225 - fpr_offset is the offset of the saved fprs
226 - lr_offset is the offset of the saved lr
227 - cr_offset is the offset of the saved cr
230 #define SIGNED_SHORT(x) \
231 ((sizeof (short) == 2) \
232 ? ((int)(short)(x)) \
233 : ((int)((((x) & 0xffff) ^ 0x8000) - 0x8000)))
235 #define GET_SRC_REG(x) (((x) >> 21) & 0x1f)
238 skip_prologue (pc
, fdata
)
240 struct rs6000_framedata
*fdata
;
242 CORE_ADDR orig_pc
= pc
;
250 int minimal_toc_loaded
= 0;
251 static struct rs6000_framedata zero_frame
;
254 fdata
->saved_gpr
= -1;
255 fdata
->saved_fpr
= -1;
256 fdata
->alloca_reg
= -1;
257 fdata
->frameless
= 1;
258 fdata
->nosavedpc
= 1;
260 if (target_read_memory (pc
, buf
, 4))
261 return pc
; /* Can't access it -- assume no prologue. */
263 /* Assume that subsequent fetches can fail with low probability. */
268 op
= read_memory_integer (pc
, 4);
270 if ((op
& 0xfc1fffff) == 0x7c0802a6) { /* mflr Rx */
271 lr_reg
= (op
& 0x03e00000) | 0x90010000;
274 } else if ((op
& 0xfc1fffff) == 0x7c000026) { /* mfcr Rx */
275 cr_reg
= (op
& 0x03e00000) | 0x90010000;
278 } else if ((op
& 0xfc1f0000) == 0xd8010000) { /* stfd Rx,NUM(r1) */
279 reg
= GET_SRC_REG (op
);
280 if (fdata
->saved_fpr
== -1 || fdata
->saved_fpr
> reg
) {
281 fdata
->saved_fpr
= reg
;
282 fdata
->fpr_offset
= SIGNED_SHORT (op
) + offset
;
286 } else if (((op
& 0xfc1f0000) == 0xbc010000) || /* stm Rx, NUM(r1) */
287 ((op
& 0xfc1f0000) == 0x90010000 && /* st rx,NUM(r1),
289 (op
& 0x03e00000) >= 0x01a00000)) {
291 reg
= GET_SRC_REG (op
);
292 if (fdata
->saved_gpr
== -1 || fdata
->saved_gpr
> reg
) {
293 fdata
->saved_gpr
= reg
;
294 fdata
->gpr_offset
= SIGNED_SHORT (op
) + offset
;
298 } else if ((op
& 0xffff0000) == 0x3c000000) { /* addis 0,0,NUM, used
300 fdata
->offset
= (op
& 0x0000ffff) << 16;
301 fdata
->frameless
= 0;
304 } else if ((op
& 0xffff0000) == 0x60000000) { /* ori 0,0,NUM, 2nd ha
305 lf of >= 32k frames */
306 fdata
->offset
|= (op
& 0x0000ffff);
307 fdata
->frameless
= 0;
310 } else if ((op
& 0xffff0000) == lr_reg
) { /* st Rx,NUM(r1)
312 fdata
->lr_offset
= SIGNED_SHORT (op
) + offset
;
313 fdata
->nosavedpc
= 0;
317 } else if ((op
& 0xffff0000) == cr_reg
) { /* st Rx,NUM(r1)
319 fdata
->cr_offset
= SIGNED_SHORT (op
) + offset
;
323 } else if (op
== 0x48000005) { /* bl .+4 used in
327 } else if (op
== 0x48000004) { /* b .+4 (xlc) */
330 } else if (((op
& 0xffff0000) == 0x801e0000 || /* lwz 0,NUM(r30), used
331 in V.4 -mrelocatable */
332 op
== 0x7fc0f214) && /* add r30,r0,r30, used
333 in V.4 -mrelocatable */
334 lr_reg
== 0x901e0000) {
337 } else if ((op
& 0xffff0000) == 0x3fc00000 || /* addis 30,0,foo@ha, used
338 in V.4 -mminimal-toc */
339 (op
& 0xffff0000) == 0x3bde0000) { /* addi 30,30,foo@l */
342 } else if ((op
& 0xfc000000) == 0x48000000) { /* bl foo,
345 fdata
->frameless
= 0;
346 /* Don't skip over the subroutine call if it is not within the first
347 three instructions of the prologue. */
348 if ((pc
- orig_pc
) > 8)
351 op
= read_memory_integer (pc
+4, 4);
353 /* At this point, make sure this is not a trampoline function
354 (a function that simply calls another functions, and nothing else).
355 If the next is not a nop, this branch was part of the function
358 if (op
== 0x4def7b82 || op
== 0) /* crorc 15, 15, 15 */
359 break; /* don't skip over
363 /* update stack pointer */
364 } else if ((op
& 0xffff0000) == 0x94210000) { /* stu r1,NUM(r1) */
365 fdata
->frameless
= 0;
366 fdata
->offset
= SIGNED_SHORT (op
);
367 offset
= fdata
->offset
;
370 } else if (op
== 0x7c21016e) { /* stwux 1,1,0 */
371 fdata
->frameless
= 0;
372 offset
= fdata
->offset
;
375 /* Load up minimal toc pointer */
376 } else if ((op
>> 22) == 0x20f
377 && ! minimal_toc_loaded
) { /* l r31,... or l r30,... */
378 minimal_toc_loaded
= 1;
381 /* store parameters in stack */
382 } else if ((op
& 0xfc1f0000) == 0x90010000 || /* st rx,NUM(r1) */
383 (op
& 0xfc1f0000) == 0xd8010000 || /* stfd Rx,NUM(r1) */
384 (op
& 0xfc1f0000) == 0xfc010000) { /* frsp, fp?,NUM(r1) */
387 /* store parameters in stack via frame pointer */
389 ((op
& 0xfc1f0000) == 0x901f0000 || /* st rx,NUM(r1) */
390 (op
& 0xfc1f0000) == 0xd81f0000 || /* stfd Rx,NUM(r1) */
391 (op
& 0xfc1f0000) == 0xfc1f0000)) { /* frsp, fp?,NUM(r1) */
394 /* Set up frame pointer */
395 } else if (op
== 0x603f0000 /* oril r31, r1, 0x0 */
396 || op
== 0x7c3f0b78) { /* mr r31, r1 */
397 fdata
->frameless
= 0;
399 fdata
->alloca_reg
= 31;
402 /* Another way to set up the frame pointer. */
403 } else if ((op
& 0xfc1fffff) == 0x38010000) { /* addi rX, r1, 0x0 */
404 fdata
->frameless
= 0;
406 fdata
->alloca_reg
= (op
& ~0x38010000) >> 21;
415 /* I have problems with skipping over __main() that I need to address
416 * sometime. Previously, I used to use misc_function_vector which
417 * didn't work as well as I wanted to be. -MGO */
419 /* If the first thing after skipping a prolog is a branch to a function,
420 this might be a call to an initializer in main(), introduced by gcc2.
421 We'd like to skip over it as well. Fortunately, xlc does some extra
422 work before calling a function right after a prologue, thus we can
423 single out such gcc2 behaviour. */
426 if ((op
& 0xfc000001) == 0x48000001) { /* bl foo, an initializer function? */
427 op
= read_memory_integer (pc
+4, 4);
429 if (op
== 0x4def7b82) { /* cror 0xf, 0xf, 0xf (nop) */
431 /* check and see if we are in main. If so, skip over this initializer
434 tmp
= find_pc_misc_function (pc
);
435 if (tmp
>= 0 && STREQ (misc_function_vector
[tmp
].name
, "main"))
441 fdata
->offset
= - fdata
->offset
;
446 /*************************************************************************
447 Support for creating pushind a dummy frame into the stack, and popping
449 *************************************************************************/
451 /* The total size of dummy frame is 436, which is;
456 and 24 extra bytes for the callee's link area. The last 24 bytes
457 for the link area might not be necessary, since it will be taken
458 care of by push_arguments(). */
460 #define DUMMY_FRAME_SIZE 436
462 #define DUMMY_FRAME_ADDR_SIZE 10
464 /* Make sure you initialize these in somewhere, in case gdb gives up what it
465 was debugging and starts debugging something else. FIXMEibm */
467 static int dummy_frame_count
= 0;
468 static int dummy_frame_size
= 0;
469 static CORE_ADDR
*dummy_frame_addr
= 0;
471 extern int stop_stack_dummy
;
473 /* push a dummy frame into stack, save all register. Currently we are saving
474 only gpr's and fpr's, which is not good enough! FIXMEmgo */
481 /* Same thing, target byte order. */
486 /* Same thing, target byte order. */
489 /* Needed to figure out where to save the dummy link area.
490 FIXME: There should be an easier way to do this, no? tiemann 9/9/95. */
491 struct rs6000_framedata fdata
;
495 target_fetch_registers (-1);
497 if (dummy_frame_count
>= dummy_frame_size
) {
498 dummy_frame_size
+= DUMMY_FRAME_ADDR_SIZE
;
499 if (dummy_frame_addr
)
500 dummy_frame_addr
= (CORE_ADDR
*) xrealloc
501 (dummy_frame_addr
, sizeof(CORE_ADDR
) * (dummy_frame_size
));
503 dummy_frame_addr
= (CORE_ADDR
*)
504 xmalloc (sizeof(CORE_ADDR
) * (dummy_frame_size
));
507 sp
= read_register(SP_REGNUM
);
508 pc
= read_register(PC_REGNUM
);
509 store_address (pc_targ
, 4, pc
);
511 skip_prologue (get_pc_function_start (pc
) + FUNCTION_START_OFFSET
, &fdata
);
513 dummy_frame_addr
[dummy_frame_count
++] = sp
;
515 /* Be careful! If the stack pointer is not decremented first, then kernel
516 thinks he is free to use the space underneath it. And kernel actually
517 uses that area for IPC purposes when executing ptrace(2) calls. So
518 before writing register values into the new frame, decrement and update
519 %sp first in order to secure your frame. */
521 /* FIXME: We don't check if the stack really has this much space.
522 This is a problem on the ppc simulator (which only grants one page
523 (4096 bytes) by default. */
525 write_register (SP_REGNUM
, sp
-DUMMY_FRAME_SIZE
);
527 /* gdb relies on the state of current_frame. We'd better update it,
528 otherwise things like do_registers_info() wouldn't work properly! */
530 flush_cached_frames ();
532 /* save program counter in link register's space. */
533 write_memory (sp
+ (fdata
.lr_offset
? fdata
.lr_offset
: DEFAULT_LR_SAVE
),
536 /* save all floating point and general purpose registers here. */
539 for (ii
= 0; ii
< 32; ++ii
)
540 write_memory (sp
-8-(ii
*8), ®isters
[REGISTER_BYTE (31-ii
+FP0_REGNUM
)], 8);
543 for (ii
=1; ii
<=32; ++ii
)
544 write_memory (sp
-256-(ii
*4), ®isters
[REGISTER_BYTE (32-ii
)], 4);
546 /* so far, 32*2 + 32 words = 384 bytes have been written.
547 7 extra registers in our register set: pc, ps, cnd, lr, cnt, xer, mq */
549 for (ii
=1; ii
<= (LAST_SP_REGNUM
-FIRST_SP_REGNUM
+1); ++ii
) {
550 write_memory (sp
-384-(ii
*4),
551 ®isters
[REGISTER_BYTE (FPLAST_REGNUM
+ ii
)], 4);
554 /* Save sp or so called back chain right here. */
555 store_address (sp_targ
, 4, sp
);
556 write_memory (sp
-DUMMY_FRAME_SIZE
, sp_targ
, 4);
557 sp
-= DUMMY_FRAME_SIZE
;
559 /* And finally, this is the back chain. */
560 write_memory (sp
+8, pc_targ
, 4);
564 /* Pop a dummy frame.
566 In rs6000 when we push a dummy frame, we save all of the registers. This
567 is usually done before user calls a function explicitly.
569 After a dummy frame is pushed, some instructions are copied into stack,
570 and stack pointer is decremented even more. Since we don't have a frame
571 pointer to get back to the parent frame of the dummy, we start having
572 trouble poping it. Therefore, we keep a dummy frame stack, keeping
573 addresses of dummy frames as such. When poping happens and when we
574 detect that was a dummy frame, we pop it back to its parent by using
575 dummy frame stack (`dummy_frame_addr' array).
577 FIXME: This whole concept is broken. You should be able to detect
578 a dummy stack frame *on the user's stack itself*. When you do,
579 then you know the format of that stack frame -- including its
580 saved SP register! There should *not* be a separate stack in the
581 GDB process that keeps track of these dummy frames! -- gnu@cygnus.com Aug92
589 sp
= dummy_frame_addr
[--dummy_frame_count
];
591 /* restore all fpr's. */
592 for (ii
= 1; ii
<= 32; ++ii
)
593 read_memory (sp
-(ii
*8), ®isters
[REGISTER_BYTE (32-ii
+FP0_REGNUM
)], 8);
595 /* restore all gpr's */
596 for (ii
=1; ii
<= 32; ++ii
) {
597 read_memory (sp
-256-(ii
*4), ®isters
[REGISTER_BYTE (32-ii
)], 4);
600 /* restore the rest of the registers. */
601 for (ii
=1; ii
<=(LAST_SP_REGNUM
-FIRST_SP_REGNUM
+1); ++ii
)
602 read_memory (sp
-384-(ii
*4),
603 ®isters
[REGISTER_BYTE (FPLAST_REGNUM
+ ii
)], 4);
605 read_memory (sp
-(DUMMY_FRAME_SIZE
-8),
606 ®isters
[REGISTER_BYTE(PC_REGNUM
)], 4);
608 /* when a dummy frame was being pushed, we had to decrement %sp first, in
609 order to secure astack space. Thus, saved %sp (or %r1) value, is not the
610 one we should restore. Change it with the one we need. */
612 memcpy (®isters
[REGISTER_BYTE(FP_REGNUM
)], (char *) &sp
, sizeof (int));
614 /* Now we can restore all registers. */
616 target_store_registers (-1);
618 flush_cached_frames ();
622 /* pop the innermost frame, go back to the caller. */
627 CORE_ADDR pc
, lr
, sp
, prev_sp
; /* %pc, %lr, %sp */
628 struct rs6000_framedata fdata
;
629 struct frame_info
*frame
= get_current_frame ();
633 sp
= FRAME_FP (frame
);
635 if (stop_stack_dummy
)
637 #ifdef USE_GENERIC_DUMMY_FRAMES
638 generic_pop_dummy_frame ();
639 flush_cached_frames ();
642 if (dummy_frame_count
)
648 /* Make sure that all registers are valid. */
649 read_register_bytes (0, NULL
, REGISTER_BYTES
);
651 /* figure out previous %pc value. If the function is frameless, it is
652 still in the link register, otherwise walk the frames and retrieve the
653 saved %pc value in the previous frame. */
655 addr
= get_pc_function_start (frame
->pc
) + FUNCTION_START_OFFSET
;
656 (void) skip_prologue (addr
, &fdata
);
661 prev_sp
= read_memory_integer (sp
, 4);
662 if (fdata
.lr_offset
== 0)
663 lr
= read_register (LR_REGNUM
);
665 lr
= read_memory_integer (prev_sp
+ fdata
.lr_offset
, 4);
667 /* reset %pc value. */
668 write_register (PC_REGNUM
, lr
);
670 /* reset register values if any was saved earlier. */
671 addr
= prev_sp
- fdata
.offset
;
673 if (fdata
.saved_gpr
!= -1)
674 for (ii
= fdata
.saved_gpr
; ii
<= 31; ++ii
) {
675 read_memory (addr
, ®isters
[REGISTER_BYTE (ii
)], 4);
679 if (fdata
.saved_fpr
!= -1)
680 for (ii
= fdata
.saved_fpr
; ii
<= 31; ++ii
) {
681 read_memory (addr
, ®isters
[REGISTER_BYTE (ii
+FP0_REGNUM
)], 8);
685 write_register (SP_REGNUM
, prev_sp
);
686 target_store_registers (-1);
687 flush_cached_frames ();
690 /* fixup the call sequence of a dummy function, with the real function address.
691 its argumets will be passed by gdb. */
694 rs6000_fix_call_dummy (dummyname
, pc
, fun
, nargs
, args
, type
, gcc_p
)
703 #define TOC_ADDR_OFFSET 20
704 #define TARGET_ADDR_OFFSET 28
707 CORE_ADDR target_addr
;
709 if (find_toc_address_hook
!= NULL
)
713 tocvalue
= (*find_toc_address_hook
) (fun
);
714 ii
= *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
);
715 ii
= (ii
& 0xffff0000) | (tocvalue
>> 16);
716 *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
) = ii
;
718 ii
= *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
+4);
719 ii
= (ii
& 0xffff0000) | (tocvalue
& 0x0000ffff);
720 *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
+4) = ii
;
724 ii
= *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
);
725 ii
= (ii
& 0xffff0000) | (target_addr
>> 16);
726 *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
) = ii
;
728 ii
= *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
+4);
729 ii
= (ii
& 0xffff0000) | (target_addr
& 0x0000ffff);
730 *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
+4) = ii
;
733 /* Pass the arguments in either registers, or in the stack. In RS6000,
734 the first eight words of the argument list (that might be less than
735 eight parameters if some parameters occupy more than one word) are
736 passed in r3..r11 registers. float and double parameters are
737 passed in fpr's, in addition to that. Rest of the parameters if any
738 are passed in user stack. There might be cases in which half of the
739 parameter is copied into registers, the other half is pushed into
742 If the function is returning a structure, then the return address is passed
743 in r3, then the first 7 words of the parameters can be passed in registers,
747 push_arguments (nargs
, args
, sp
, struct_return
, struct_addr
)
752 CORE_ADDR struct_addr
;
756 int argno
; /* current argument number */
757 int argbytes
; /* current argument byte */
758 char tmp_buffer
[50];
759 int f_argno
= 0; /* current floating point argno */
766 #ifndef USE_GENERIC_DUMMY_FRAMES
767 if ( dummy_frame_count
<= 0)
768 printf_unfiltered ("FATAL ERROR -push_arguments()! frame not found!!\n");
769 #endif /* GENERIC_DUMMY_FRAMES */
771 /* The first eight words of ther arguments are passed in registers. Copy
774 If the function is returning a `struct', then the first word (which
775 will be passed in r3) is used for struct return address. In that
776 case we should advance one word and start from r4 register to copy
779 ii
= struct_return
? 1 : 0;
782 effectively indirect call... gcc does...
784 return_val example( float, int);
787 float in fp0, int in r3
788 offset of stack on overflow 8/16
789 for varargs, must go by type.
791 float in r3&r4, int in r5
792 offset of stack on overflow different
794 return in r3 or f0. If no float, must study how gcc emulates floats;
795 pay attention to arg promotion.
796 User may have to cast\args to handle promotion correctly
797 since gdb won't know if prototype supplied or not.
800 for (argno
=0, argbytes
=0; argno
< nargs
&& ii
<8; ++ii
) {
803 type
= check_typedef (VALUE_TYPE (arg
));
804 len
= TYPE_LENGTH (type
);
806 if (TYPE_CODE (type
) == TYPE_CODE_FLT
) {
808 /* floating point arguments are passed in fpr's, as well as gpr's.
809 There are 13 fpr's reserved for passing parameters. At this point
810 there is no way we would run out of them. */
814 "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno
);
816 memcpy (®isters
[REGISTER_BYTE(FP0_REGNUM
+ 1 + f_argno
)],
817 VALUE_CONTENTS (arg
),
824 /* Argument takes more than one register. */
825 while (argbytes
< len
) {
826 memset (®isters
[REGISTER_BYTE(ii
+3)], 0, sizeof(int));
827 memcpy (®isters
[REGISTER_BYTE(ii
+3)],
828 ((char*)VALUE_CONTENTS (arg
))+argbytes
,
829 (len
- argbytes
) > 4 ? 4 : len
- argbytes
);
833 goto ran_out_of_registers_for_arguments
;
838 else { /* Argument can fit in one register. No problem. */
839 memset (®isters
[REGISTER_BYTE(ii
+3)], 0, sizeof(int));
840 memcpy (®isters
[REGISTER_BYTE(ii
+3)], VALUE_CONTENTS (arg
), len
);
845 ran_out_of_registers_for_arguments
:
847 #ifdef USE_GENERIC_DUMMY_FRAMES
848 saved_sp
= read_sp ();
850 /* location for 8 parameters are always reserved. */
853 /* another six words for back chain, TOC register, link register, etc. */
855 #endif /* GENERIC_DUMMY_FRAMES */
856 /* if there are more arguments, allocate space for them in
857 the stack, then push them starting from the ninth one. */
859 if ((argno
< nargs
) || argbytes
) {
863 space
+= ((len
- argbytes
+ 3) & -4);
869 for (; jj
< nargs
; ++jj
) {
870 value_ptr val
= args
[jj
];
871 space
+= ((TYPE_LENGTH (VALUE_TYPE (val
))) + 3) & -4;
874 /* add location required for the rest of the parameters */
875 space
= (space
+ 7) & -8;
878 /* This is another instance we need to be concerned about securing our
879 stack space. If we write anything underneath %sp (r1), we might conflict
880 with the kernel who thinks he is free to use this area. So, update %sp
881 first before doing anything else. */
883 write_register (SP_REGNUM
, sp
);
885 /* if the last argument copied into the registers didn't fit there
886 completely, push the rest of it into stack. */
889 write_memory (sp
+24+(ii
*4),
890 ((char*)VALUE_CONTENTS (arg
))+argbytes
,
893 ii
+= ((len
- argbytes
+ 3) & -4) / 4;
896 /* push the rest of the arguments into stack. */
897 for (; argno
< nargs
; ++argno
) {
900 type
= check_typedef (VALUE_TYPE (arg
));
901 len
= TYPE_LENGTH (type
);
904 /* float types should be passed in fpr's, as well as in the stack. */
905 if (TYPE_CODE (type
) == TYPE_CODE_FLT
&& f_argno
< 13) {
909 "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno
);
911 memcpy (®isters
[REGISTER_BYTE(FP0_REGNUM
+ 1 + f_argno
)],
912 VALUE_CONTENTS (arg
),
917 write_memory (sp
+24+(ii
*4), (char *) VALUE_CONTENTS (arg
), len
);
918 ii
+= ((len
+ 3) & -4) / 4;
922 /* Secure stack areas first, before doing anything else. */
923 write_register (SP_REGNUM
, sp
);
925 #ifndef USE_GENERIC_DUMMY_FRAMES
926 /* we want to copy 24 bytes of target's frame to dummy's frame,
927 then set back chain to point to new frame. */
929 saved_sp
= dummy_frame_addr
[dummy_frame_count
- 1];
930 read_memory (saved_sp
, tmp_buffer
, 24);
931 write_memory (sp
, tmp_buffer
, 24);
932 #endif /* GENERIC_DUMMY_FRAMES */
934 /* set back chain properly */
935 store_address (tmp_buffer
, 4, saved_sp
);
936 write_memory (sp
, tmp_buffer
, 4);
938 target_store_registers (-1);
941 #ifdef ELF_OBJECT_FORMAT
943 /* Function: ppc_push_return_address (pc, sp)
944 Set up the return address for the inferior function call. */
947 ppc_push_return_address (pc
, sp
)
951 write_register (LR_REGNUM
, CALL_DUMMY_ADDRESS ());
957 /* a given return value in `regbuf' with a type `valtype', extract and copy its
958 value into `valbuf' */
961 extract_return_value (valtype
, regbuf
, valbuf
)
962 struct type
*valtype
;
963 char regbuf
[REGISTER_BYTES
];
968 if (TYPE_CODE (valtype
) == TYPE_CODE_FLT
) {
971 /* floats and doubles are returned in fpr1. fpr's have a size of 8 bytes.
972 We need to truncate the return value into float size (4 byte) if
975 if (TYPE_LENGTH (valtype
) > 4) /* this is a double */
977 ®buf
[REGISTER_BYTE (FP0_REGNUM
+ 1)],
978 TYPE_LENGTH (valtype
));
980 memcpy (&dd
, ®buf
[REGISTER_BYTE (FP0_REGNUM
+ 1)], 8);
982 memcpy (valbuf
, &ff
, sizeof(float));
986 /* return value is copied starting from r3. */
987 if (TARGET_BYTE_ORDER
== BIG_ENDIAN
988 && TYPE_LENGTH (valtype
) < REGISTER_RAW_SIZE (3))
989 offset
= REGISTER_RAW_SIZE (3) - TYPE_LENGTH (valtype
);
992 regbuf
+ REGISTER_BYTE (3) + offset
,
993 TYPE_LENGTH (valtype
));
998 /* keep structure return address in this variable.
999 FIXME: This is a horrid kludge which should not be allowed to continue
1000 living. This only allows a single nested call to a structure-returning
1001 function. Come on, guys! -- gnu@cygnus.com, Aug 92 */
1003 CORE_ADDR rs6000_struct_return_address
;
1006 /* Indirect function calls use a piece of trampoline code to do context
1007 switching, i.e. to set the new TOC table. Skip such code if we are on
1008 its first instruction (as when we have single-stepped to here).
1009 Also skip shared library trampoline code (which is different from
1010 indirect function call trampolines).
1011 Result is desired PC to step until, or NULL if we are not in
1015 skip_trampoline_code (pc
)
1018 register unsigned int ii
, op
;
1019 CORE_ADDR solib_target_pc
;
1021 static unsigned trampoline_code
[] = {
1022 0x800b0000, /* l r0,0x0(r11) */
1023 0x90410014, /* st r2,0x14(r1) */
1024 0x7c0903a6, /* mtctr r0 */
1025 0x804b0004, /* l r2,0x4(r11) */
1026 0x816b0008, /* l r11,0x8(r11) */
1027 0x4e800420, /* bctr */
1028 0x4e800020, /* br */
1032 /* If pc is in a shared library trampoline, return its target. */
1033 solib_target_pc
= find_solib_trampoline_target (pc
);
1034 if (solib_target_pc
)
1035 return solib_target_pc
;
1037 for (ii
=0; trampoline_code
[ii
]; ++ii
) {
1038 op
= read_memory_integer (pc
+ (ii
*4), 4);
1039 if (op
!= trampoline_code
[ii
])
1042 ii
= read_register (11); /* r11 holds destination addr */
1043 pc
= read_memory_integer (ii
, 4); /* (r11) value */
1047 /* Determines whether the function FI has a frame on the stack or not. */
1050 frameless_function_invocation (fi
)
1051 struct frame_info
*fi
;
1053 CORE_ADDR func_start
;
1054 struct rs6000_framedata fdata
;
1056 /* Don't even think about framelessness except on the innermost frame
1057 or if the function was interrupted by a signal. */
1058 if (fi
->next
!= NULL
&& !fi
->next
->signal_handler_caller
)
1061 func_start
= get_pc_function_start (fi
->pc
);
1063 /* If we failed to find the start of the function, it is a mistake
1064 to inspect the instructions. */
1068 /* A frame with a zero PC is usually created by dereferencing a NULL
1069 function pointer, normally causing an immediate core dump of the
1070 inferior. Mark function as frameless, as the inferior has no chance
1071 of setting up a stack frame. */
1078 func_start
+= FUNCTION_START_OFFSET
;
1079 (void) skip_prologue (func_start
, &fdata
);
1080 return fdata
.frameless
;
1083 /* Return the PC saved in a frame */
1087 struct frame_info
*fi
;
1089 CORE_ADDR func_start
;
1090 struct rs6000_framedata fdata
;
1092 if (fi
->signal_handler_caller
)
1093 return read_memory_integer (fi
->frame
+ SIG_FRAME_PC_OFFSET
, 4);
1095 #ifdef USE_GENERIC_DUMMY_FRAMES
1096 if (PC_IN_CALL_DUMMY (fi
->pc
, fi
->frame
, fi
->frame
))
1097 return generic_read_register_dummy(fi
->pc
, fi
->frame
, PC_REGNUM
);
1098 #endif /* GENERIC_DUMMY_FRAMES */
1100 func_start
= get_pc_function_start (fi
->pc
) + FUNCTION_START_OFFSET
;
1102 /* If we failed to find the start of the function, it is a mistake
1103 to inspect the instructions. */
1107 (void) skip_prologue (func_start
, &fdata
);
1109 if (fdata
.lr_offset
== 0 && fi
->next
!= NULL
)
1111 if (fi
->next
->signal_handler_caller
)
1112 return read_memory_integer (fi
->next
->frame
+ SIG_FRAME_LR_OFFSET
, 4);
1114 return read_memory_integer (rs6000_frame_chain (fi
) + DEFAULT_LR_SAVE
,
1118 if (fdata
.lr_offset
== 0)
1119 return read_register (LR_REGNUM
);
1121 return read_memory_integer (rs6000_frame_chain (fi
) + fdata
.lr_offset
, 4);
1124 /* If saved registers of frame FI are not known yet, read and cache them.
1125 &FDATAP contains rs6000_framedata; TDATAP can be NULL,
1126 in which case the framedata are read. */
1129 frame_get_cache_fsr (fi
, fdatap
)
1130 struct frame_info
*fi
;
1131 struct rs6000_framedata
*fdatap
;
1134 CORE_ADDR frame_addr
;
1135 struct rs6000_framedata work_fdata
;
1140 if (fdatap
== NULL
) {
1141 fdatap
= &work_fdata
;
1142 (void) skip_prologue (get_pc_function_start (fi
->pc
), fdatap
);
1145 fi
->cache_fsr
= (struct frame_saved_regs
*)
1146 obstack_alloc (&frame_cache_obstack
, sizeof (struct frame_saved_regs
));
1147 memset (fi
->cache_fsr
, '\0', sizeof (struct frame_saved_regs
));
1149 if (fi
->prev
&& fi
->prev
->frame
)
1150 frame_addr
= fi
->prev
->frame
;
1152 frame_addr
= read_memory_integer (fi
->frame
, 4);
1154 /* if != -1, fdatap->saved_fpr is the smallest number of saved_fpr.
1155 All fpr's from saved_fpr to fp31 are saved. */
1157 if (fdatap
->saved_fpr
>= 0) {
1158 int fpr_offset
= frame_addr
+ fdatap
->fpr_offset
;
1159 for (ii
= fdatap
->saved_fpr
; ii
< 32; ii
++) {
1160 fi
->cache_fsr
->regs
[FP0_REGNUM
+ ii
] = fpr_offset
;
1165 /* if != -1, fdatap->saved_gpr is the smallest number of saved_gpr.
1166 All gpr's from saved_gpr to gpr31 are saved. */
1168 if (fdatap
->saved_gpr
>= 0) {
1169 int gpr_offset
= frame_addr
+ fdatap
->gpr_offset
;
1170 for (ii
= fdatap
->saved_gpr
; ii
< 32; ii
++) {
1171 fi
->cache_fsr
->regs
[ii
] = gpr_offset
;
1176 /* If != 0, fdatap->cr_offset is the offset from the frame that holds
1178 if (fdatap
->cr_offset
!= 0)
1179 fi
->cache_fsr
->regs
[CR_REGNUM
] = frame_addr
+ fdatap
->cr_offset
;
1181 /* If != 0, fdatap->lr_offset is the offset from the frame that holds
1183 if (fdatap
->lr_offset
!= 0)
1184 fi
->cache_fsr
->regs
[LR_REGNUM
] = frame_addr
+ fdatap
->lr_offset
;
1187 /* Return the address of a frame. This is the inital %sp value when the frame
1188 was first allocated. For functions calling alloca(), it might be saved in
1189 an alloca register. */
1192 frame_initial_stack_address (fi
)
1193 struct frame_info
*fi
;
1196 struct rs6000_framedata fdata
;
1197 struct frame_info
*callee_fi
;
1199 /* if the initial stack pointer (frame address) of this frame is known,
1203 return fi
->initial_sp
;
1205 /* find out if this function is using an alloca register.. */
1207 (void) skip_prologue (get_pc_function_start (fi
->pc
), &fdata
);
1209 /* if saved registers of this frame are not known yet, read and cache them. */
1212 frame_get_cache_fsr (fi
, &fdata
);
1214 /* If no alloca register used, then fi->frame is the value of the %sp for
1215 this frame, and it is good enough. */
1217 if (fdata
.alloca_reg
< 0) {
1218 fi
->initial_sp
= fi
->frame
;
1219 return fi
->initial_sp
;
1222 /* This function has an alloca register. If this is the top-most frame
1223 (with the lowest address), the value in alloca register is good. */
1226 return fi
->initial_sp
= read_register (fdata
.alloca_reg
);
1228 /* Otherwise, this is a caller frame. Callee has usually already saved
1229 registers, but there are exceptions (such as when the callee
1230 has no parameters). Find the address in which caller's alloca
1231 register is saved. */
1233 for (callee_fi
= fi
->next
; callee_fi
; callee_fi
= callee_fi
->next
) {
1235 if (!callee_fi
->cache_fsr
)
1236 frame_get_cache_fsr (callee_fi
, NULL
);
1238 /* this is the address in which alloca register is saved. */
1240 tmpaddr
= callee_fi
->cache_fsr
->regs
[fdata
.alloca_reg
];
1242 fi
->initial_sp
= read_memory_integer (tmpaddr
, 4);
1243 return fi
->initial_sp
;
1246 /* Go look into deeper levels of the frame chain to see if any one of
1247 the callees has saved alloca register. */
1250 /* If alloca register was not saved, by the callee (or any of its callees)
1251 then the value in the register is still good. */
1253 return fi
->initial_sp
= read_register (fdata
.alloca_reg
);
1257 rs6000_frame_chain (thisframe
)
1258 struct frame_info
*thisframe
;
1262 #ifdef USE_GENERIC_DUMMY_FRAMES
1263 if (PC_IN_CALL_DUMMY (thisframe
->pc
, thisframe
->frame
, thisframe
->frame
))
1264 return thisframe
->frame
; /* dummy frame same as caller's frame */
1265 #endif /* GENERIC_DUMMY_FRAMES */
1267 if (inside_entry_file (thisframe
->pc
) ||
1268 thisframe
->pc
== entry_point_address ())
1271 if (thisframe
->signal_handler_caller
)
1272 fp
= read_memory_integer (thisframe
->frame
+ SIG_FRAME_FP_OFFSET
, 4);
1273 else if (thisframe
->next
!= NULL
1274 && thisframe
->next
->signal_handler_caller
1275 && frameless_function_invocation (thisframe
))
1276 /* A frameless function interrupted by a signal did not change the
1278 fp
= FRAME_FP (thisframe
);
1280 fp
= read_memory_integer ((thisframe
)->frame
, 4);
1282 #ifdef USE_GENERIC_DUMMY_FRAMES
1286 lr
= read_register (LR_REGNUM
);
1287 if (lr
== entry_point_address ())
1288 if (fp
!= 0 && (fpp
= read_memory_integer (fp
, 4)) != 0)
1289 if (PC_IN_CALL_DUMMY (lr
, fpp
, fpp
))
1292 #endif /* GENERIC_DUMMY_FRAMES */
1296 /* Return nonzero if ADDR (a function pointer) is in the data space and
1297 is therefore a special function pointer. */
1300 is_magic_function_pointer (addr
)
1303 struct obj_section
*s
;
1305 s
= find_pc_section (addr
);
1306 if (s
&& s
->the_bfd_section
->flags
& SEC_CODE
)
1312 #ifdef GDB_TARGET_POWERPC
1314 gdb_print_insn_powerpc (memaddr
, info
)
1316 disassemble_info
*info
;
1318 if (TARGET_BYTE_ORDER
== BIG_ENDIAN
)
1319 return print_insn_big_powerpc (memaddr
, info
);
1321 return print_insn_little_powerpc (memaddr
, info
);
1325 /* Function: get_saved_register
1326 Just call the generic_get_saved_register function. */
1328 #ifdef USE_GENERIC_DUMMY_FRAMES
1330 get_saved_register (raw_buffer
, optimized
, addrp
, frame
, regnum
, lval
)
1334 struct frame_info
*frame
;
1336 enum lval_type
*lval
;
1338 generic_get_saved_register (raw_buffer
, optimized
, addrp
,
1339 frame
, regnum
, lval
);
1345 _initialize_rs6000_tdep ()
1347 /* FIXME, this should not be decided via ifdef. */
1348 #ifdef GDB_TARGET_POWERPC
1349 tm_print_insn
= gdb_print_insn_powerpc
;
1351 tm_print_insn
= print_insn_rs6000
;