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 /* Nonzero if we just simulated a single step break. */
38 /* Breakpoint shadows for the single step instructions will be kept here. */
40 static struct sstep_breaks
{
41 /* Address, or 0 if this is not in use. */
43 /* Shadow contents. */
47 /* Hook for determining the TOC address when calling functions in the
48 inferior under AIX. The initialization code in rs6000-nat.c sets
49 this hook to point to find_toc_address. */
51 CORE_ADDR (*find_toc_address_hook
) PARAMS ((CORE_ADDR
)) = NULL
;
53 /* Static function prototypes */
55 static CORE_ADDR branch_dest
PARAMS ((int opcode
, int instr
, CORE_ADDR pc
,
58 static void frame_get_cache_fsr
PARAMS ((struct frame_info
*fi
,
59 struct rs6000_framedata
*fdatap
));
61 static void pop_dummy_frame
PARAMS ((void));
63 /* Calculate the destination of a branch/jump. Return -1 if not a branch. */
66 branch_dest (opcode
, instr
, pc
, safety
)
77 absolute
= (int) ((instr
>> 1) & 1);
81 immediate
= ((instr
& ~3) << 6) >> 6; /* br unconditional */
85 dest
= pc
+ immediate
;
89 immediate
= ((instr
& ~3) << 16) >> 16; /* br conditional */
93 dest
= pc
+ immediate
;
97 ext_op
= (instr
>>1) & 0x3ff;
99 if (ext_op
== 16) /* br conditional register */
101 dest
= read_register (LR_REGNUM
) & ~3;
103 /* If we are about to return from a signal handler, dest is
104 something like 0x3c90. The current frame is a signal handler
105 caller frame, upon completion of the sigreturn system call
106 execution will return to the saved PC in the frame. */
107 if (dest
< TEXT_SEGMENT_BASE
)
109 struct frame_info
*fi
;
111 fi
= get_current_frame ();
113 dest
= read_memory_integer (fi
->frame
+ SIG_FRAME_PC_OFFSET
,
118 else if (ext_op
== 528) /* br cond to count reg */
120 dest
= read_register (CTR_REGNUM
) & ~3;
122 /* If we are about to execute a system call, dest is something
123 like 0x22fc or 0x3b00. Upon completion the system call
124 will return to the address in the link register. */
125 if (dest
< TEXT_SEGMENT_BASE
)
126 dest
= read_register (LR_REGNUM
) & ~3;
133 return (dest
< TEXT_SEGMENT_BASE
) ? safety
: dest
;
137 /* Sequence of bytes for breakpoint instruction. */
139 #define BIG_BREAKPOINT { 0x7d, 0x82, 0x10, 0x08 }
140 #define LITTLE_BREAKPOINT { 0x08, 0x10, 0x82, 0x7d }
143 rs6000_breakpoint_from_pc (bp_addr
, bp_size
)
147 static unsigned char *big_breakpoint
= BIG_BREAKPOINT
;
148 static unsigned char *little_breakpoint
= LITTLE_BREAKPOINT
;
150 if (TARGET_BYTE_ORDER
== BIG_ENDIAN
)
151 return big_breakpoint
;
153 return little_breakpoint
;
157 /* AIX does not support PT_STEP. Simulate it. */
161 enum target_signal signal
;
163 #define INSNLEN(OPCODE) 4
165 static char le_breakp
[] = LITTLE_BREAKPOINT
;
166 static char be_breakp
[] = BIG_BREAKPOINT
;
167 char *breakp
= TARGET_BYTE_ORDER
== BIG_ENDIAN
? be_breakp
: le_breakp
;
176 insn
= read_memory_integer (loc
, 4);
178 breaks
[0] = loc
+ INSNLEN(insn
);
180 breaks
[1] = branch_dest (opcode
, insn
, loc
, breaks
[0]);
182 /* Don't put two breakpoints on the same address. */
183 if (breaks
[1] == breaks
[0])
186 stepBreaks
[1].address
= 0;
188 for (ii
=0; ii
< 2; ++ii
) {
190 /* ignore invalid breakpoint. */
191 if ( breaks
[ii
] == -1)
194 read_memory (breaks
[ii
], stepBreaks
[ii
].data
, 4);
196 write_memory (breaks
[ii
], breakp
, 4);
197 stepBreaks
[ii
].address
= breaks
[ii
];
203 /* remove step breakpoints. */
204 for (ii
=0; ii
< 2; ++ii
)
205 if (stepBreaks
[ii
].address
!= 0)
207 (stepBreaks
[ii
].address
, stepBreaks
[ii
].data
, 4);
211 errno
= 0; /* FIXME, don't ignore errors! */
212 /* What errors? {read,write}_memory call error(). */
216 /* return pc value after skipping a function prologue and also return
217 information about a function frame.
219 in struct rs6000_frameinfo fdata:
220 - frameless is TRUE, if function does not have a frame.
221 - nosavedpc is TRUE, if function does not save %pc value in its frame.
222 - offset is the number of bytes used in the frame to save registers.
223 - saved_gpr is the number of the first saved gpr.
224 - saved_fpr is the number of the first saved fpr.
225 - alloca_reg is the number of the register used for alloca() handling.
227 - gpr_offset is the offset of the saved gprs
228 - fpr_offset is the offset of the saved fprs
229 - lr_offset is the offset of the saved lr
230 - cr_offset is the offset of the saved cr
233 #define SIGNED_SHORT(x) \
234 ((sizeof (short) == 2) \
235 ? ((int)(short)(x)) \
236 : ((int)((((x) & 0xffff) ^ 0x8000) - 0x8000)))
238 #define GET_SRC_REG(x) (((x) >> 21) & 0x1f)
241 skip_prologue (pc
, fdata
)
243 struct rs6000_framedata
*fdata
;
245 CORE_ADDR orig_pc
= pc
;
253 int minimal_toc_loaded
= 0;
254 static struct rs6000_framedata zero_frame
;
257 fdata
->saved_gpr
= -1;
258 fdata
->saved_fpr
= -1;
259 fdata
->alloca_reg
= -1;
260 fdata
->frameless
= 1;
261 fdata
->nosavedpc
= 1;
263 if (target_read_memory (pc
, buf
, 4))
264 return pc
; /* Can't access it -- assume no prologue. */
266 /* Assume that subsequent fetches can fail with low probability. */
271 op
= read_memory_integer (pc
, 4);
273 if ((op
& 0xfc1fffff) == 0x7c0802a6) { /* mflr Rx */
274 lr_reg
= (op
& 0x03e00000) | 0x90010000;
277 } else if ((op
& 0xfc1fffff) == 0x7c000026) { /* mfcr Rx */
278 cr_reg
= (op
& 0x03e00000) | 0x90010000;
281 } else if ((op
& 0xfc1f0000) == 0xd8010000) { /* stfd Rx,NUM(r1) */
282 reg
= GET_SRC_REG (op
);
283 if (fdata
->saved_fpr
== -1 || fdata
->saved_fpr
> reg
) {
284 fdata
->saved_fpr
= reg
;
285 fdata
->fpr_offset
= SIGNED_SHORT (op
) + offset
;
289 } else if (((op
& 0xfc1f0000) == 0xbc010000) || /* stm Rx, NUM(r1) */
290 ((op
& 0xfc1f0000) == 0x90010000 && /* st rx,NUM(r1),
292 (op
& 0x03e00000) >= 0x01a00000)) {
294 reg
= GET_SRC_REG (op
);
295 if (fdata
->saved_gpr
== -1 || fdata
->saved_gpr
> reg
) {
296 fdata
->saved_gpr
= reg
;
297 fdata
->gpr_offset
= SIGNED_SHORT (op
) + offset
;
301 } else if ((op
& 0xffff0000) == 0x3c000000) { /* addis 0,0,NUM, used
303 fdata
->offset
= (op
& 0x0000ffff) << 16;
304 fdata
->frameless
= 0;
307 } else if ((op
& 0xffff0000) == 0x60000000) { /* ori 0,0,NUM, 2nd ha
308 lf of >= 32k frames */
309 fdata
->offset
|= (op
& 0x0000ffff);
310 fdata
->frameless
= 0;
313 } else if ((op
& 0xffff0000) == lr_reg
) { /* st Rx,NUM(r1)
315 fdata
->lr_offset
= SIGNED_SHORT (op
) + offset
;
316 fdata
->nosavedpc
= 0;
320 } else if ((op
& 0xffff0000) == cr_reg
) { /* st Rx,NUM(r1)
322 fdata
->cr_offset
= SIGNED_SHORT (op
) + offset
;
326 } else if (op
== 0x48000005) { /* bl .+4 used in
330 } else if (op
== 0x48000004) { /* b .+4 (xlc) */
333 } else if (((op
& 0xffff0000) == 0x801e0000 || /* lwz 0,NUM(r30), used
334 in V.4 -mrelocatable */
335 op
== 0x7fc0f214) && /* add r30,r0,r30, used
336 in V.4 -mrelocatable */
337 lr_reg
== 0x901e0000) {
340 } else if ((op
& 0xffff0000) == 0x3fc00000 || /* addis 30,0,foo@ha, used
341 in V.4 -mminimal-toc */
342 (op
& 0xffff0000) == 0x3bde0000) { /* addi 30,30,foo@l */
345 } else if ((op
& 0xfc000000) == 0x48000000) { /* bl foo,
348 fdata
->frameless
= 0;
349 /* Don't skip over the subroutine call if it is not within the first
350 three instructions of the prologue. */
351 if ((pc
- orig_pc
) > 8)
354 op
= read_memory_integer (pc
+4, 4);
356 /* At this point, make sure this is not a trampoline function
357 (a function that simply calls another functions, and nothing else).
358 If the next is not a nop, this branch was part of the function
361 if (op
== 0x4def7b82 || op
== 0) /* crorc 15, 15, 15 */
362 break; /* don't skip over
366 /* update stack pointer */
367 } else if ((op
& 0xffff0000) == 0x94210000) { /* stu r1,NUM(r1) */
368 fdata
->frameless
= 0;
369 fdata
->offset
= SIGNED_SHORT (op
);
370 offset
= fdata
->offset
;
373 } else if (op
== 0x7c21016e) { /* stwux 1,1,0 */
374 fdata
->frameless
= 0;
375 offset
= fdata
->offset
;
378 /* Load up minimal toc pointer */
379 } else if ((op
>> 22) == 0x20f
380 && ! minimal_toc_loaded
) { /* l r31,... or l r30,... */
381 minimal_toc_loaded
= 1;
384 /* store parameters in stack */
385 } else if ((op
& 0xfc1f0000) == 0x90010000 || /* st rx,NUM(r1) */
386 (op
& 0xfc1f0000) == 0xd8010000 || /* stfd Rx,NUM(r1) */
387 (op
& 0xfc1f0000) == 0xfc010000) { /* frsp, fp?,NUM(r1) */
390 /* store parameters in stack via frame pointer */
392 ((op
& 0xfc1f0000) == 0x901f0000 || /* st rx,NUM(r1) */
393 (op
& 0xfc1f0000) == 0xd81f0000 || /* stfd Rx,NUM(r1) */
394 (op
& 0xfc1f0000) == 0xfc1f0000)) { /* frsp, fp?,NUM(r1) */
397 /* Set up frame pointer */
398 } else if (op
== 0x603f0000 /* oril r31, r1, 0x0 */
399 || op
== 0x7c3f0b78) { /* mr r31, r1 */
400 fdata
->frameless
= 0;
402 fdata
->alloca_reg
= 31;
405 /* Another way to set up the frame pointer. */
406 } else if ((op
& 0xfc1fffff) == 0x38010000) { /* addi rX, r1, 0x0 */
407 fdata
->frameless
= 0;
409 fdata
->alloca_reg
= (op
& ~0x38010000) >> 21;
418 /* I have problems with skipping over __main() that I need to address
419 * sometime. Previously, I used to use misc_function_vector which
420 * didn't work as well as I wanted to be. -MGO */
422 /* If the first thing after skipping a prolog is a branch to a function,
423 this might be a call to an initializer in main(), introduced by gcc2.
424 We'd like to skip over it as well. Fortunately, xlc does some extra
425 work before calling a function right after a prologue, thus we can
426 single out such gcc2 behaviour. */
429 if ((op
& 0xfc000001) == 0x48000001) { /* bl foo, an initializer function? */
430 op
= read_memory_integer (pc
+4, 4);
432 if (op
== 0x4def7b82) { /* cror 0xf, 0xf, 0xf (nop) */
434 /* check and see if we are in main. If so, skip over this initializer
437 tmp
= find_pc_misc_function (pc
);
438 if (tmp
>= 0 && STREQ (misc_function_vector
[tmp
].name
, "main"))
444 fdata
->offset
= - fdata
->offset
;
449 /*************************************************************************
450 Support for creating pushind a dummy frame into the stack, and popping
452 *************************************************************************/
454 /* The total size of dummy frame is 436, which is;
459 and 24 extra bytes for the callee's link area. The last 24 bytes
460 for the link area might not be necessary, since it will be taken
461 care of by push_arguments(). */
463 #define DUMMY_FRAME_SIZE 436
465 #define DUMMY_FRAME_ADDR_SIZE 10
467 /* Make sure you initialize these in somewhere, in case gdb gives up what it
468 was debugging and starts debugging something else. FIXMEibm */
470 static int dummy_frame_count
= 0;
471 static int dummy_frame_size
= 0;
472 static CORE_ADDR
*dummy_frame_addr
= 0;
474 extern int stop_stack_dummy
;
476 /* push a dummy frame into stack, save all register. Currently we are saving
477 only gpr's and fpr's, which is not good enough! FIXMEmgo */
484 /* Same thing, target byte order. */
489 /* Same thing, target byte order. */
492 /* Needed to figure out where to save the dummy link area.
493 FIXME: There should be an easier way to do this, no? tiemann 9/9/95. */
494 struct rs6000_framedata fdata
;
498 target_fetch_registers (-1);
500 if (dummy_frame_count
>= dummy_frame_size
) {
501 dummy_frame_size
+= DUMMY_FRAME_ADDR_SIZE
;
502 if (dummy_frame_addr
)
503 dummy_frame_addr
= (CORE_ADDR
*) xrealloc
504 (dummy_frame_addr
, sizeof(CORE_ADDR
) * (dummy_frame_size
));
506 dummy_frame_addr
= (CORE_ADDR
*)
507 xmalloc (sizeof(CORE_ADDR
) * (dummy_frame_size
));
510 sp
= read_register(SP_REGNUM
);
511 pc
= read_register(PC_REGNUM
);
512 store_address (pc_targ
, 4, pc
);
514 skip_prologue (get_pc_function_start (pc
) + FUNCTION_START_OFFSET
, &fdata
);
516 dummy_frame_addr
[dummy_frame_count
++] = sp
;
518 /* Be careful! If the stack pointer is not decremented first, then kernel
519 thinks he is free to use the space underneath it. And kernel actually
520 uses that area for IPC purposes when executing ptrace(2) calls. So
521 before writing register values into the new frame, decrement and update
522 %sp first in order to secure your frame. */
524 /* FIXME: We don't check if the stack really has this much space.
525 This is a problem on the ppc simulator (which only grants one page
526 (4096 bytes) by default. */
528 write_register (SP_REGNUM
, sp
-DUMMY_FRAME_SIZE
);
530 /* gdb relies on the state of current_frame. We'd better update it,
531 otherwise things like do_registers_info() wouldn't work properly! */
533 flush_cached_frames ();
535 /* save program counter in link register's space. */
536 write_memory (sp
+ (fdata
.lr_offset
? fdata
.lr_offset
: DEFAULT_LR_SAVE
),
539 /* save all floating point and general purpose registers here. */
542 for (ii
= 0; ii
< 32; ++ii
)
543 write_memory (sp
-8-(ii
*8), ®isters
[REGISTER_BYTE (31-ii
+FP0_REGNUM
)], 8);
546 for (ii
=1; ii
<=32; ++ii
)
547 write_memory (sp
-256-(ii
*4), ®isters
[REGISTER_BYTE (32-ii
)], 4);
549 /* so far, 32*2 + 32 words = 384 bytes have been written.
550 7 extra registers in our register set: pc, ps, cnd, lr, cnt, xer, mq */
552 for (ii
=1; ii
<= (LAST_SP_REGNUM
-FIRST_SP_REGNUM
+1); ++ii
) {
553 write_memory (sp
-384-(ii
*4),
554 ®isters
[REGISTER_BYTE (FPLAST_REGNUM
+ ii
)], 4);
557 /* Save sp or so called back chain right here. */
558 store_address (sp_targ
, 4, sp
);
559 write_memory (sp
-DUMMY_FRAME_SIZE
, sp_targ
, 4);
560 sp
-= DUMMY_FRAME_SIZE
;
562 /* And finally, this is the back chain. */
563 write_memory (sp
+8, pc_targ
, 4);
567 /* Pop a dummy frame.
569 In rs6000 when we push a dummy frame, we save all of the registers. This
570 is usually done before user calls a function explicitly.
572 After a dummy frame is pushed, some instructions are copied into stack,
573 and stack pointer is decremented even more. Since we don't have a frame
574 pointer to get back to the parent frame of the dummy, we start having
575 trouble poping it. Therefore, we keep a dummy frame stack, keeping
576 addresses of dummy frames as such. When poping happens and when we
577 detect that was a dummy frame, we pop it back to its parent by using
578 dummy frame stack (`dummy_frame_addr' array).
580 FIXME: This whole concept is broken. You should be able to detect
581 a dummy stack frame *on the user's stack itself*. When you do,
582 then you know the format of that stack frame -- including its
583 saved SP register! There should *not* be a separate stack in the
584 GDB process that keeps track of these dummy frames! -- gnu@cygnus.com Aug92
592 sp
= dummy_frame_addr
[--dummy_frame_count
];
594 /* restore all fpr's. */
595 for (ii
= 1; ii
<= 32; ++ii
)
596 read_memory (sp
-(ii
*8), ®isters
[REGISTER_BYTE (32-ii
+FP0_REGNUM
)], 8);
598 /* restore all gpr's */
599 for (ii
=1; ii
<= 32; ++ii
) {
600 read_memory (sp
-256-(ii
*4), ®isters
[REGISTER_BYTE (32-ii
)], 4);
603 /* restore the rest of the registers. */
604 for (ii
=1; ii
<=(LAST_SP_REGNUM
-FIRST_SP_REGNUM
+1); ++ii
)
605 read_memory (sp
-384-(ii
*4),
606 ®isters
[REGISTER_BYTE (FPLAST_REGNUM
+ ii
)], 4);
608 read_memory (sp
-(DUMMY_FRAME_SIZE
-8),
609 ®isters
[REGISTER_BYTE(PC_REGNUM
)], 4);
611 /* when a dummy frame was being pushed, we had to decrement %sp first, in
612 order to secure astack space. Thus, saved %sp (or %r1) value, is not the
613 one we should restore. Change it with the one we need. */
615 memcpy (®isters
[REGISTER_BYTE(FP_REGNUM
)], (char *) &sp
, sizeof (int));
617 /* Now we can restore all registers. */
619 target_store_registers (-1);
621 flush_cached_frames ();
625 /* pop the innermost frame, go back to the caller. */
630 CORE_ADDR pc
, lr
, sp
, prev_sp
; /* %pc, %lr, %sp */
631 struct rs6000_framedata fdata
;
632 struct frame_info
*frame
= get_current_frame ();
636 sp
= FRAME_FP (frame
);
638 if (stop_stack_dummy
)
640 #ifdef USE_GENERIC_DUMMY_FRAMES
641 generic_pop_dummy_frame ();
642 flush_cached_frames ();
645 if (dummy_frame_count
)
651 /* Make sure that all registers are valid. */
652 read_register_bytes (0, NULL
, REGISTER_BYTES
);
654 /* figure out previous %pc value. If the function is frameless, it is
655 still in the link register, otherwise walk the frames and retrieve the
656 saved %pc value in the previous frame. */
658 addr
= get_pc_function_start (frame
->pc
) + FUNCTION_START_OFFSET
;
659 (void) skip_prologue (addr
, &fdata
);
664 prev_sp
= read_memory_integer (sp
, 4);
665 if (fdata
.lr_offset
== 0)
666 lr
= read_register (LR_REGNUM
);
668 lr
= read_memory_integer (prev_sp
+ fdata
.lr_offset
, 4);
670 /* reset %pc value. */
671 write_register (PC_REGNUM
, lr
);
673 /* reset register values if any was saved earlier. */
674 addr
= prev_sp
- fdata
.offset
;
676 if (fdata
.saved_gpr
!= -1)
677 for (ii
= fdata
.saved_gpr
; ii
<= 31; ++ii
) {
678 read_memory (addr
, ®isters
[REGISTER_BYTE (ii
)], 4);
682 if (fdata
.saved_fpr
!= -1)
683 for (ii
= fdata
.saved_fpr
; ii
<= 31; ++ii
) {
684 read_memory (addr
, ®isters
[REGISTER_BYTE (ii
+FP0_REGNUM
)], 8);
688 write_register (SP_REGNUM
, prev_sp
);
689 target_store_registers (-1);
690 flush_cached_frames ();
693 /* fixup the call sequence of a dummy function, with the real function address.
694 its argumets will be passed by gdb. */
697 rs6000_fix_call_dummy (dummyname
, pc
, fun
, nargs
, args
, type
, gcc_p
)
706 #define TOC_ADDR_OFFSET 20
707 #define TARGET_ADDR_OFFSET 28
710 CORE_ADDR target_addr
;
712 if (find_toc_address_hook
!= NULL
)
716 tocvalue
= (*find_toc_address_hook
) (fun
);
717 ii
= *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
);
718 ii
= (ii
& 0xffff0000) | (tocvalue
>> 16);
719 *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
) = ii
;
721 ii
= *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
+4);
722 ii
= (ii
& 0xffff0000) | (tocvalue
& 0x0000ffff);
723 *(int*)((char*)dummyname
+ TOC_ADDR_OFFSET
+4) = ii
;
727 ii
= *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
);
728 ii
= (ii
& 0xffff0000) | (target_addr
>> 16);
729 *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
) = ii
;
731 ii
= *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
+4);
732 ii
= (ii
& 0xffff0000) | (target_addr
& 0x0000ffff);
733 *(int*)((char*)dummyname
+ TARGET_ADDR_OFFSET
+4) = ii
;
736 /* Pass the arguments in either registers, or in the stack. In RS6000,
737 the first eight words of the argument list (that might be less than
738 eight parameters if some parameters occupy more than one word) are
739 passed in r3..r11 registers. float and double parameters are
740 passed in fpr's, in addition to that. Rest of the parameters if any
741 are passed in user stack. There might be cases in which half of the
742 parameter is copied into registers, the other half is pushed into
745 If the function is returning a structure, then the return address is passed
746 in r3, then the first 7 words of the parameters can be passed in registers,
750 push_arguments (nargs
, args
, sp
, struct_return
, struct_addr
)
755 CORE_ADDR struct_addr
;
759 int argno
; /* current argument number */
760 int argbytes
; /* current argument byte */
761 char tmp_buffer
[50];
762 int f_argno
= 0; /* current floating point argno */
769 #ifndef USE_GENERIC_DUMMY_FRAMES
770 if ( dummy_frame_count
<= 0)
771 printf_unfiltered ("FATAL ERROR -push_arguments()! frame not found!!\n");
772 #endif /* GENERIC_DUMMY_FRAMES */
774 /* The first eight words of ther arguments are passed in registers. Copy
777 If the function is returning a `struct', then the first word (which
778 will be passed in r3) is used for struct return address. In that
779 case we should advance one word and start from r4 register to copy
782 ii
= struct_return
? 1 : 0;
785 effectively indirect call... gcc does...
787 return_val example( float, int);
790 float in fp0, int in r3
791 offset of stack on overflow 8/16
792 for varargs, must go by type.
794 float in r3&r4, int in r5
795 offset of stack on overflow different
797 return in r3 or f0. If no float, must study how gcc emulates floats;
798 pay attention to arg promotion.
799 User may have to cast\args to handle promotion correctly
800 since gdb won't know if prototype supplied or not.
803 for (argno
=0, argbytes
=0; argno
< nargs
&& ii
<8; ++ii
) {
806 type
= check_typedef (VALUE_TYPE (arg
));
807 len
= TYPE_LENGTH (type
);
809 if (TYPE_CODE (type
) == TYPE_CODE_FLT
) {
811 /* floating point arguments are passed in fpr's, as well as gpr's.
812 There are 13 fpr's reserved for passing parameters. At this point
813 there is no way we would run out of them. */
817 "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno
);
819 memcpy (®isters
[REGISTER_BYTE(FP0_REGNUM
+ 1 + f_argno
)],
820 VALUE_CONTENTS (arg
),
827 /* Argument takes more than one register. */
828 while (argbytes
< len
) {
829 memset (®isters
[REGISTER_BYTE(ii
+3)], 0, sizeof(int));
830 memcpy (®isters
[REGISTER_BYTE(ii
+3)],
831 ((char*)VALUE_CONTENTS (arg
))+argbytes
,
832 (len
- argbytes
) > 4 ? 4 : len
- argbytes
);
836 goto ran_out_of_registers_for_arguments
;
841 else { /* Argument can fit in one register. No problem. */
842 memset (®isters
[REGISTER_BYTE(ii
+3)], 0, sizeof(int));
843 memcpy (®isters
[REGISTER_BYTE(ii
+3)], VALUE_CONTENTS (arg
), len
);
848 ran_out_of_registers_for_arguments
:
850 #ifdef USE_GENERIC_DUMMY_FRAMES
851 saved_sp
= read_sp ();
853 /* location for 8 parameters are always reserved. */
856 /* another six words for back chain, TOC register, link register, etc. */
858 #endif /* GENERIC_DUMMY_FRAMES */
859 /* if there are more arguments, allocate space for them in
860 the stack, then push them starting from the ninth one. */
862 if ((argno
< nargs
) || argbytes
) {
866 space
+= ((len
- argbytes
+ 3) & -4);
872 for (; jj
< nargs
; ++jj
) {
873 value_ptr val
= args
[jj
];
874 space
+= ((TYPE_LENGTH (VALUE_TYPE (val
))) + 3) & -4;
877 /* add location required for the rest of the parameters */
878 space
= (space
+ 7) & -8;
881 /* This is another instance we need to be concerned about securing our
882 stack space. If we write anything underneath %sp (r1), we might conflict
883 with the kernel who thinks he is free to use this area. So, update %sp
884 first before doing anything else. */
886 write_register (SP_REGNUM
, sp
);
888 /* if the last argument copied into the registers didn't fit there
889 completely, push the rest of it into stack. */
892 write_memory (sp
+24+(ii
*4),
893 ((char*)VALUE_CONTENTS (arg
))+argbytes
,
896 ii
+= ((len
- argbytes
+ 3) & -4) / 4;
899 /* push the rest of the arguments into stack. */
900 for (; argno
< nargs
; ++argno
) {
903 type
= check_typedef (VALUE_TYPE (arg
));
904 len
= TYPE_LENGTH (type
);
907 /* float types should be passed in fpr's, as well as in the stack. */
908 if (TYPE_CODE (type
) == TYPE_CODE_FLT
&& f_argno
< 13) {
912 "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno
);
914 memcpy (®isters
[REGISTER_BYTE(FP0_REGNUM
+ 1 + f_argno
)],
915 VALUE_CONTENTS (arg
),
920 write_memory (sp
+24+(ii
*4), (char *) VALUE_CONTENTS (arg
), len
);
921 ii
+= ((len
+ 3) & -4) / 4;
925 /* Secure stack areas first, before doing anything else. */
926 write_register (SP_REGNUM
, sp
);
928 #ifndef USE_GENERIC_DUMMY_FRAMES
929 /* we want to copy 24 bytes of target's frame to dummy's frame,
930 then set back chain to point to new frame. */
932 saved_sp
= dummy_frame_addr
[dummy_frame_count
- 1];
933 read_memory (saved_sp
, tmp_buffer
, 24);
934 write_memory (sp
, tmp_buffer
, 24);
935 #endif /* GENERIC_DUMMY_FRAMES */
937 /* set back chain properly */
938 store_address (tmp_buffer
, 4, saved_sp
);
939 write_memory (sp
, tmp_buffer
, 4);
941 target_store_registers (-1);
944 #ifdef ELF_OBJECT_FORMAT
946 /* Function: ppc_push_return_address (pc, sp)
947 Set up the return address for the inferior function call. */
950 ppc_push_return_address (pc
, sp
)
954 write_register (LR_REGNUM
, CALL_DUMMY_ADDRESS ());
960 /* a given return value in `regbuf' with a type `valtype', extract and copy its
961 value into `valbuf' */
964 extract_return_value (valtype
, regbuf
, valbuf
)
965 struct type
*valtype
;
966 char regbuf
[REGISTER_BYTES
];
971 if (TYPE_CODE (valtype
) == TYPE_CODE_FLT
) {
974 /* floats and doubles are returned in fpr1. fpr's have a size of 8 bytes.
975 We need to truncate the return value into float size (4 byte) if
978 if (TYPE_LENGTH (valtype
) > 4) /* this is a double */
980 ®buf
[REGISTER_BYTE (FP0_REGNUM
+ 1)],
981 TYPE_LENGTH (valtype
));
983 memcpy (&dd
, ®buf
[REGISTER_BYTE (FP0_REGNUM
+ 1)], 8);
985 memcpy (valbuf
, &ff
, sizeof(float));
989 /* return value is copied starting from r3. */
990 if (TARGET_BYTE_ORDER
== BIG_ENDIAN
991 && TYPE_LENGTH (valtype
) < REGISTER_RAW_SIZE (3))
992 offset
= REGISTER_RAW_SIZE (3) - TYPE_LENGTH (valtype
);
995 regbuf
+ REGISTER_BYTE (3) + offset
,
996 TYPE_LENGTH (valtype
));
1001 /* keep structure return address in this variable.
1002 FIXME: This is a horrid kludge which should not be allowed to continue
1003 living. This only allows a single nested call to a structure-returning
1004 function. Come on, guys! -- gnu@cygnus.com, Aug 92 */
1006 CORE_ADDR rs6000_struct_return_address
;
1009 /* Indirect function calls use a piece of trampoline code to do context
1010 switching, i.e. to set the new TOC table. Skip such code if we are on
1011 its first instruction (as when we have single-stepped to here).
1012 Also skip shared library trampoline code (which is different from
1013 indirect function call trampolines).
1014 Result is desired PC to step until, or NULL if we are not in
1018 skip_trampoline_code (pc
)
1021 register unsigned int ii
, op
;
1022 CORE_ADDR solib_target_pc
;
1024 static unsigned trampoline_code
[] = {
1025 0x800b0000, /* l r0,0x0(r11) */
1026 0x90410014, /* st r2,0x14(r1) */
1027 0x7c0903a6, /* mtctr r0 */
1028 0x804b0004, /* l r2,0x4(r11) */
1029 0x816b0008, /* l r11,0x8(r11) */
1030 0x4e800420, /* bctr */
1031 0x4e800020, /* br */
1035 /* If pc is in a shared library trampoline, return its target. */
1036 solib_target_pc
= find_solib_trampoline_target (pc
);
1037 if (solib_target_pc
)
1038 return solib_target_pc
;
1040 for (ii
=0; trampoline_code
[ii
]; ++ii
) {
1041 op
= read_memory_integer (pc
+ (ii
*4), 4);
1042 if (op
!= trampoline_code
[ii
])
1045 ii
= read_register (11); /* r11 holds destination addr */
1046 pc
= read_memory_integer (ii
, 4); /* (r11) value */
1050 /* Determines whether the function FI has a frame on the stack or not. */
1053 frameless_function_invocation (fi
)
1054 struct frame_info
*fi
;
1056 CORE_ADDR func_start
;
1057 struct rs6000_framedata fdata
;
1059 /* Don't even think about framelessness except on the innermost frame
1060 or if the function was interrupted by a signal. */
1061 if (fi
->next
!= NULL
&& !fi
->next
->signal_handler_caller
)
1064 func_start
= get_pc_function_start (fi
->pc
);
1066 /* If we failed to find the start of the function, it is a mistake
1067 to inspect the instructions. */
1071 /* A frame with a zero PC is usually created by dereferencing a NULL
1072 function pointer, normally causing an immediate core dump of the
1073 inferior. Mark function as frameless, as the inferior has no chance
1074 of setting up a stack frame. */
1081 func_start
+= FUNCTION_START_OFFSET
;
1082 (void) skip_prologue (func_start
, &fdata
);
1083 return fdata
.frameless
;
1086 /* Return the PC saved in a frame */
1090 struct frame_info
*fi
;
1092 CORE_ADDR func_start
;
1093 struct rs6000_framedata fdata
;
1095 if (fi
->signal_handler_caller
)
1096 return read_memory_integer (fi
->frame
+ SIG_FRAME_PC_OFFSET
, 4);
1098 #ifdef USE_GENERIC_DUMMY_FRAMES
1099 if (PC_IN_CALL_DUMMY (fi
->pc
, fi
->frame
, fi
->frame
))
1100 return generic_read_register_dummy(fi
->pc
, fi
->frame
, PC_REGNUM
);
1101 #endif /* GENERIC_DUMMY_FRAMES */
1103 func_start
= get_pc_function_start (fi
->pc
) + FUNCTION_START_OFFSET
;
1105 /* If we failed to find the start of the function, it is a mistake
1106 to inspect the instructions. */
1110 (void) skip_prologue (func_start
, &fdata
);
1112 if (fdata
.lr_offset
== 0 && fi
->next
!= NULL
)
1114 if (fi
->next
->signal_handler_caller
)
1115 return read_memory_integer (fi
->next
->frame
+ SIG_FRAME_LR_OFFSET
, 4);
1117 return read_memory_integer (rs6000_frame_chain (fi
) + DEFAULT_LR_SAVE
,
1121 if (fdata
.lr_offset
== 0)
1122 return read_register (LR_REGNUM
);
1124 return read_memory_integer (rs6000_frame_chain (fi
) + fdata
.lr_offset
, 4);
1127 /* If saved registers of frame FI are not known yet, read and cache them.
1128 &FDATAP contains rs6000_framedata; TDATAP can be NULL,
1129 in which case the framedata are read. */
1132 frame_get_cache_fsr (fi
, fdatap
)
1133 struct frame_info
*fi
;
1134 struct rs6000_framedata
*fdatap
;
1137 CORE_ADDR frame_addr
;
1138 struct rs6000_framedata work_fdata
;
1143 if (fdatap
== NULL
) {
1144 fdatap
= &work_fdata
;
1145 (void) skip_prologue (get_pc_function_start (fi
->pc
), fdatap
);
1148 fi
->cache_fsr
= (struct frame_saved_regs
*)
1149 obstack_alloc (&frame_cache_obstack
, sizeof (struct frame_saved_regs
));
1150 memset (fi
->cache_fsr
, '\0', sizeof (struct frame_saved_regs
));
1152 if (fi
->prev
&& fi
->prev
->frame
)
1153 frame_addr
= fi
->prev
->frame
;
1155 frame_addr
= read_memory_integer (fi
->frame
, 4);
1157 /* if != -1, fdatap->saved_fpr is the smallest number of saved_fpr.
1158 All fpr's from saved_fpr to fp31 are saved. */
1160 if (fdatap
->saved_fpr
>= 0) {
1161 int fpr_offset
= frame_addr
+ fdatap
->fpr_offset
;
1162 for (ii
= fdatap
->saved_fpr
; ii
< 32; ii
++) {
1163 fi
->cache_fsr
->regs
[FP0_REGNUM
+ ii
] = fpr_offset
;
1168 /* if != -1, fdatap->saved_gpr is the smallest number of saved_gpr.
1169 All gpr's from saved_gpr to gpr31 are saved. */
1171 if (fdatap
->saved_gpr
>= 0) {
1172 int gpr_offset
= frame_addr
+ fdatap
->gpr_offset
;
1173 for (ii
= fdatap
->saved_gpr
; ii
< 32; ii
++) {
1174 fi
->cache_fsr
->regs
[ii
] = gpr_offset
;
1179 /* If != 0, fdatap->cr_offset is the offset from the frame that holds
1181 if (fdatap
->cr_offset
!= 0)
1182 fi
->cache_fsr
->regs
[CR_REGNUM
] = frame_addr
+ fdatap
->cr_offset
;
1184 /* If != 0, fdatap->lr_offset is the offset from the frame that holds
1186 if (fdatap
->lr_offset
!= 0)
1187 fi
->cache_fsr
->regs
[LR_REGNUM
] = frame_addr
+ fdatap
->lr_offset
;
1190 /* Return the address of a frame. This is the inital %sp value when the frame
1191 was first allocated. For functions calling alloca(), it might be saved in
1192 an alloca register. */
1195 frame_initial_stack_address (fi
)
1196 struct frame_info
*fi
;
1199 struct rs6000_framedata fdata
;
1200 struct frame_info
*callee_fi
;
1202 /* if the initial stack pointer (frame address) of this frame is known,
1206 return fi
->initial_sp
;
1208 /* find out if this function is using an alloca register.. */
1210 (void) skip_prologue (get_pc_function_start (fi
->pc
), &fdata
);
1212 /* if saved registers of this frame are not known yet, read and cache them. */
1215 frame_get_cache_fsr (fi
, &fdata
);
1217 /* If no alloca register used, then fi->frame is the value of the %sp for
1218 this frame, and it is good enough. */
1220 if (fdata
.alloca_reg
< 0) {
1221 fi
->initial_sp
= fi
->frame
;
1222 return fi
->initial_sp
;
1225 /* This function has an alloca register. If this is the top-most frame
1226 (with the lowest address), the value in alloca register is good. */
1229 return fi
->initial_sp
= read_register (fdata
.alloca_reg
);
1231 /* Otherwise, this is a caller frame. Callee has usually already saved
1232 registers, but there are exceptions (such as when the callee
1233 has no parameters). Find the address in which caller's alloca
1234 register is saved. */
1236 for (callee_fi
= fi
->next
; callee_fi
; callee_fi
= callee_fi
->next
) {
1238 if (!callee_fi
->cache_fsr
)
1239 frame_get_cache_fsr (callee_fi
, NULL
);
1241 /* this is the address in which alloca register is saved. */
1243 tmpaddr
= callee_fi
->cache_fsr
->regs
[fdata
.alloca_reg
];
1245 fi
->initial_sp
= read_memory_integer (tmpaddr
, 4);
1246 return fi
->initial_sp
;
1249 /* Go look into deeper levels of the frame chain to see if any one of
1250 the callees has saved alloca register. */
1253 /* If alloca register was not saved, by the callee (or any of its callees)
1254 then the value in the register is still good. */
1256 return fi
->initial_sp
= read_register (fdata
.alloca_reg
);
1260 rs6000_frame_chain (thisframe
)
1261 struct frame_info
*thisframe
;
1265 #ifdef USE_GENERIC_DUMMY_FRAMES
1266 if (PC_IN_CALL_DUMMY (thisframe
->pc
, thisframe
->frame
, thisframe
->frame
))
1267 return thisframe
->frame
; /* dummy frame same as caller's frame */
1268 #endif /* GENERIC_DUMMY_FRAMES */
1270 if (inside_entry_file (thisframe
->pc
) ||
1271 thisframe
->pc
== entry_point_address ())
1274 if (thisframe
->signal_handler_caller
)
1275 fp
= read_memory_integer (thisframe
->frame
+ SIG_FRAME_FP_OFFSET
, 4);
1276 else if (thisframe
->next
!= NULL
1277 && thisframe
->next
->signal_handler_caller
1278 && frameless_function_invocation (thisframe
))
1279 /* A frameless function interrupted by a signal did not change the
1281 fp
= FRAME_FP (thisframe
);
1283 fp
= read_memory_integer ((thisframe
)->frame
, 4);
1285 #ifdef USE_GENERIC_DUMMY_FRAMES
1289 lr
= read_register (LR_REGNUM
);
1290 if (lr
== entry_point_address ())
1291 if (fp
!= 0 && (fpp
= read_memory_integer (fp
, 4)) != 0)
1292 if (PC_IN_CALL_DUMMY (lr
, fpp
, fpp
))
1295 #endif /* GENERIC_DUMMY_FRAMES */
1299 /* Return nonzero if ADDR (a function pointer) is in the data space and
1300 is therefore a special function pointer. */
1303 is_magic_function_pointer (addr
)
1306 struct obj_section
*s
;
1308 s
= find_pc_section (addr
);
1309 if (s
&& s
->the_bfd_section
->flags
& SEC_CODE
)
1315 #ifdef GDB_TARGET_POWERPC
1317 gdb_print_insn_powerpc (memaddr
, info
)
1319 disassemble_info
*info
;
1321 if (TARGET_BYTE_ORDER
== BIG_ENDIAN
)
1322 return print_insn_big_powerpc (memaddr
, info
);
1324 return print_insn_little_powerpc (memaddr
, info
);
1328 /* Function: get_saved_register
1329 Just call the generic_get_saved_register function. */
1331 #ifdef USE_GENERIC_DUMMY_FRAMES
1333 get_saved_register (raw_buffer
, optimized
, addrp
, frame
, regnum
, lval
)
1337 struct frame_info
*frame
;
1339 enum lval_type
*lval
;
1341 generic_get_saved_register (raw_buffer
, optimized
, addrp
,
1342 frame
, regnum
, lval
);
1348 _initialize_rs6000_tdep ()
1350 /* FIXME, this should not be decided via ifdef. */
1351 #ifdef GDB_TARGET_POWERPC
1352 tm_print_insn
= gdb_print_insn_powerpc
;
1354 tm_print_insn
= print_insn_rs6000
;