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c906108c SS |
1 | /* Target-dependent code for the Mitsubishi m32r for GDB, the GNU debugger. |
2 | Copyright 1996, Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #include "defs.h" | |
21 | #include "frame.h" | |
22 | #include "inferior.h" | |
23 | #include "obstack.h" | |
24 | #include "target.h" | |
25 | #include "value.h" | |
26 | #include "bfd.h" | |
27 | #include "gdb_string.h" | |
28 | #include "gdbcore.h" | |
29 | #include "symfile.h" | |
30 | ||
31 | /* Function: m32r_use_struct_convention | |
32 | Return nonzero if call_function should allocate stack space for a | |
33 | struct return? */ | |
34 | int | |
35 | m32r_use_struct_convention (gcc_p, type) | |
36 | int gcc_p; | |
37 | struct type *type; | |
38 | { | |
39 | return (TYPE_LENGTH (type) > 8); | |
40 | } | |
41 | ||
42 | /* Function: frame_find_saved_regs | |
43 | Return the frame_saved_regs structure for the frame. | |
44 | Doesn't really work for dummy frames, but it does pass back | |
45 | an empty frame_saved_regs, so I guess that's better than total failure */ | |
46 | ||
47 | void | |
48 | m32r_frame_find_saved_regs (fi, regaddr) | |
49 | struct frame_info *fi; | |
50 | struct frame_saved_regs *regaddr; | |
51 | { | |
52 | memcpy(regaddr, &fi->fsr, sizeof(struct frame_saved_regs)); | |
53 | } | |
54 | ||
55 | /* Turn this on if you want to see just how much instruction decoding | |
56 | if being done, its quite a lot | |
57 | */ | |
58 | #if 0 | |
59 | static void dump_insn(char * commnt,CORE_ADDR pc, int insn) | |
60 | { | |
61 | printf_filtered(" %s %08x %08x ", | |
62 | commnt,(unsigned int)pc,(unsigned int) insn); | |
63 | (*tm_print_insn)(pc,&tm_print_insn_info); | |
64 | printf_filtered("\n"); | |
65 | } | |
66 | #define insn_debug(args) { printf_filtered args; } | |
67 | #else | |
68 | #define dump_insn(a,b,c) {} | |
69 | #define insn_debug(args) {} | |
70 | #endif | |
71 | ||
72 | #define DEFAULT_SEARCH_LIMIT 44 | |
73 | ||
74 | /* Function: scan_prologue | |
75 | This function decodes the target function prologue to determine | |
76 | 1) the size of the stack frame, and 2) which registers are saved on it. | |
77 | It saves the offsets of saved regs in the frame_saved_regs argument, | |
78 | and returns the frame size. */ | |
79 | ||
80 | /* | |
81 | The sequence it currently generates is: | |
82 | ||
83 | if (varargs function) { ddi sp,#n } | |
84 | push registers | |
85 | if (additional stack <= 256) { addi sp,#-stack } | |
86 | else if (additional stack < 65k) { add3 sp,sp,#-stack | |
87 | ||
88 | } else if (additional stack) { | |
89 | seth sp,#(stack & 0xffff0000) | |
90 | or3 sp,sp,#(stack & 0x0000ffff) | |
91 | sub sp,r4 | |
92 | } | |
93 | if (frame pointer) { | |
94 | mv sp,fp | |
95 | } | |
96 | ||
97 | These instructions are scheduled like everything else, so you should stop at | |
98 | the first branch instruction. | |
99 | ||
100 | */ | |
101 | ||
102 | /* This is required by skip prologue and by m32r_init_extra_frame_info. | |
103 | The results of decoding a prologue should be cached because this | |
104 | thrashing is getting nuts. | |
105 | I am thinking of making a container class with two indexes, name and | |
106 | address. It may be better to extend the symbol table. | |
107 | */ | |
108 | ||
109 | static void decode_prologue (start_pc, scan_limit, | |
110 | pl_endptr, framelength, | |
111 | fi, fsr) | |
112 | CORE_ADDR start_pc; | |
113 | CORE_ADDR scan_limit; | |
114 | CORE_ADDR * pl_endptr; /* var parameter */ | |
115 | unsigned long * framelength; | |
116 | struct frame_info * fi; | |
117 | struct frame_saved_regs * fsr; | |
118 | { | |
119 | unsigned long framesize; | |
120 | int insn; | |
121 | int op1; | |
122 | int maybe_one_more = 0; | |
123 | CORE_ADDR after_prologue = 0; | |
124 | CORE_ADDR after_stack_adjust = 0; | |
125 | CORE_ADDR current_pc; | |
126 | ||
127 | ||
128 | framesize = 0; | |
129 | after_prologue = 0; | |
130 | insn_debug(("rd prolog l(%d)\n",scan_limit - current_pc)); | |
131 | ||
132 | for (current_pc = start_pc; current_pc < scan_limit; current_pc += 2) | |
133 | { | |
134 | ||
135 | insn = read_memory_unsigned_integer (current_pc, 2); | |
136 | dump_insn("insn-1",current_pc,insn); /* MTZ */ | |
137 | ||
138 | /* If this is a 32 bit instruction, we dont want to examine its | |
139 | immediate data as though it were an instruction */ | |
140 | if (current_pc & 0x02) | |
141 | { /* Clear the parallel execution bit from 16 bit instruction */ | |
142 | if (maybe_one_more) | |
143 | { /* The last instruction was a branch, usually terminates | |
144 | the series, but if this is a parallel instruction, | |
145 | it may be a stack framing instruction */ | |
146 | if (! (insn & 0x8000)) | |
147 | { insn_debug(("Really done")); | |
148 | break; /* nope, we are really done */ | |
149 | } | |
150 | } | |
151 | insn &= 0x7fff; /* decode this instruction further */ | |
152 | } | |
153 | else | |
154 | { | |
155 | if (maybe_one_more) | |
156 | break; /* This isnt the one more */ | |
157 | if (insn & 0x8000) | |
158 | { | |
159 | insn_debug(("32 bit insn\n")); | |
160 | if (current_pc == scan_limit) | |
161 | scan_limit += 2; /* extend the search */ | |
162 | current_pc += 2; /* skip the immediate data */ | |
163 | if (insn == 0x8faf) /* add3 sp, sp, xxxx */ | |
164 | /* add 16 bit sign-extended offset */ | |
165 | { insn_debug(("stack increment\n")); | |
166 | framesize += -((short) read_memory_unsigned_integer (current_pc, 2)); | |
167 | } | |
168 | else | |
169 | { | |
170 | if (((insn >> 8) == 0xe4) && /* ld24 r4, xxxxxx; sub sp, r4 */ | |
171 | read_memory_unsigned_integer (current_pc + 2, 2) == 0x0f24) | |
172 | { /* subtract 24 bit sign-extended negative-offset */ | |
173 | dump_insn("insn-2",current_pc+2,insn); | |
174 | insn = read_memory_unsigned_integer (current_pc - 2, 4); | |
175 | dump_insn("insn-3(l4)",current_pc -2,insn); | |
176 | if (insn & 0x00800000) /* sign extend */ | |
177 | insn |= 0xff000000; /* negative */ | |
178 | else | |
179 | insn &= 0x00ffffff; /* positive */ | |
180 | framesize += insn; | |
181 | } | |
182 | } | |
183 | after_prologue = current_pc; | |
184 | continue; | |
185 | } | |
186 | } | |
187 | op1 = insn & 0xf000; /* isolate just the first nibble */ | |
188 | ||
189 | if ((insn & 0xf0ff) == 0x207f) | |
190 | { /* st reg, @-sp */ | |
191 | int regno; | |
192 | insn_debug(("push\n")); | |
193 | #if 0 /* No, PUSH FP is not an indication that we will use a frame pointer. */ | |
194 | if (((insn & 0xffff) == 0x2d7f) && fi) | |
195 | fi->using_frame_pointer = 1; | |
196 | #endif | |
197 | framesize += 4; | |
198 | #if 0 | |
199 | /* Why should we increase the scan limit, just because we did a push? | |
200 | And if there is a reason, surely we would only want to do it if we | |
201 | had already reached the scan limit... */ | |
202 | if (current_pc == scan_limit) | |
203 | scan_limit += 2; | |
204 | #endif | |
205 | regno = ((insn >> 8) & 0xf); | |
206 | if (fsr) /* save_regs offset */ | |
207 | fsr->regs[regno] = framesize; | |
208 | after_prologue = 0; | |
209 | continue; | |
210 | } | |
211 | if ((insn >> 8) == 0x4f) /* addi sp, xx */ | |
212 | /* add 8 bit sign-extended offset */ | |
213 | { | |
214 | int stack_adjust = (char) (insn & 0xff); | |
215 | ||
216 | /* there are probably two of these stack adjustments: | |
217 | 1) A negative one in the prologue, and | |
218 | 2) A positive one in the epilogue. | |
219 | We are only interested in the first one. */ | |
220 | ||
221 | if (stack_adjust < 0) | |
222 | { | |
223 | framesize -= stack_adjust; | |
224 | after_prologue = 0; | |
225 | /* A frameless function may have no "mv fp, sp". | |
226 | In that case, this is the end of the prologue. */ | |
227 | after_stack_adjust = current_pc + 2; | |
228 | } | |
229 | continue; | |
230 | } | |
231 | if (insn == 0x1d8f) { /* mv fp, sp */ | |
232 | if (fi) | |
233 | fi->using_frame_pointer = 1; /* fp is now valid */ | |
234 | insn_debug(("done fp found\n")); | |
235 | after_prologue = current_pc + 2; | |
236 | break; /* end of stack adjustments */ | |
237 | } | |
238 | if (insn == 0x7000) /* Nop looks like a branch, continue explicitly */ | |
239 | { insn_debug(("nop\n")); | |
240 | after_prologue = current_pc + 2; | |
241 | continue; /* nop occurs between pushes */ | |
242 | } | |
243 | /* End of prolog if any of these are branch instructions */ | |
244 | if ((op1 == 0x7000) | |
245 | || ( op1 == 0xb000) | |
246 | || (op1 == 0x7000)) | |
247 | { | |
248 | after_prologue = current_pc; | |
249 | insn_debug(("Done: branch\n")); | |
250 | maybe_one_more = 1; | |
251 | continue; | |
252 | } | |
253 | /* Some of the branch instructions are mixed with other types */ | |
254 | if (op1 == 0x1000) | |
255 | {int subop = insn & 0x0ff0; | |
256 | if ((subop == 0x0ec0) || (subop == 0x0fc0)) | |
257 | { insn_debug(("done: jmp\n")); | |
258 | after_prologue = current_pc; | |
259 | maybe_one_more = 1; | |
260 | continue; /* jmp , jl */ | |
261 | } | |
262 | } | |
263 | } | |
264 | ||
265 | if (current_pc >= scan_limit) | |
266 | { | |
267 | if (pl_endptr) | |
7a292a7a | 268 | { |
c906108c | 269 | #if 1 |
7a292a7a SS |
270 | if (after_stack_adjust != 0) |
271 | /* We did not find a "mv fp,sp", but we DID find | |
272 | a stack_adjust. Is it safe to use that as the | |
273 | end of the prologue? I just don't know. */ | |
274 | { | |
275 | *pl_endptr = after_stack_adjust; | |
276 | if (framelength) | |
277 | *framelength = framesize; | |
278 | } | |
279 | else | |
c906108c | 280 | #endif |
7a292a7a SS |
281 | /* We reached the end of the loop without finding the end |
282 | of the prologue. No way to win -- we should report failure. | |
283 | The way we do that is to return the original start_pc. | |
284 | GDB will set a breakpoint at the start of the function (etc.) */ | |
285 | *pl_endptr = start_pc; | |
286 | } | |
c906108c SS |
287 | return; |
288 | } | |
289 | if (after_prologue == 0) | |
290 | after_prologue = current_pc; | |
291 | ||
292 | insn_debug((" framesize %d, firstline %08x\n",framesize,after_prologue)); | |
293 | if (framelength) | |
294 | *framelength = framesize; | |
295 | if (pl_endptr) | |
296 | *pl_endptr = after_prologue; | |
297 | } /* decode_prologue */ | |
298 | ||
299 | /* Function: skip_prologue | |
300 | Find end of function prologue */ | |
301 | ||
302 | CORE_ADDR | |
303 | m32r_skip_prologue (pc) | |
304 | CORE_ADDR pc; | |
305 | { | |
306 | CORE_ADDR func_addr, func_end; | |
307 | struct symtab_and_line sal; | |
308 | ||
309 | /* See what the symbol table says */ | |
310 | ||
311 | if (find_pc_partial_function (pc, NULL, &func_addr, &func_end)) | |
312 | { | |
313 | sal = find_pc_line (func_addr, 0); | |
314 | ||
315 | if (sal.line != 0 && sal.end <= func_end) | |
316 | { | |
317 | ||
318 | insn_debug(("BP after prologue %08x\n",sal.end)); | |
319 | func_end = sal.end; | |
320 | } | |
321 | else | |
322 | /* Either there's no line info, or the line after the prologue is after | |
323 | the end of the function. In this case, there probably isn't a | |
324 | prologue. */ | |
325 | { | |
326 | insn_debug(("No line info, line(%x) sal_end(%x) funcend(%x)\n", | |
327 | sal.line,sal.end,func_end)); | |
328 | func_end = min(func_end,func_addr + DEFAULT_SEARCH_LIMIT); | |
329 | } | |
330 | } | |
331 | else | |
332 | func_end = pc + DEFAULT_SEARCH_LIMIT; | |
333 | decode_prologue (pc, func_end, &sal.end, 0, 0, 0); | |
334 | return sal.end; | |
335 | } | |
336 | ||
337 | static unsigned long | |
338 | m32r_scan_prologue (fi, fsr) | |
339 | struct frame_info *fi; | |
340 | struct frame_saved_regs *fsr; | |
341 | { | |
342 | struct symtab_and_line sal; | |
343 | CORE_ADDR prologue_start, prologue_end, current_pc; | |
344 | unsigned long framesize; | |
345 | ||
346 | /* this code essentially duplicates skip_prologue, | |
347 | but we need the start address below. */ | |
348 | ||
349 | if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end)) | |
350 | { | |
351 | sal = find_pc_line (prologue_start, 0); | |
352 | ||
353 | if (sal.line == 0) /* no line info, use current PC */ | |
354 | if (prologue_start == entry_point_address ()) | |
355 | return 0; | |
356 | } | |
357 | else | |
358 | { | |
359 | prologue_start = fi->pc; | |
360 | prologue_end = prologue_start + 48; /* We're in the boondocks: | |
361 | allow for 16 pushes, an add, | |
362 | and "mv fp,sp" */ | |
363 | } | |
364 | #if 0 | |
365 | prologue_end = min (prologue_end, fi->pc); | |
366 | #endif | |
367 | insn_debug(("fipc(%08x) start(%08x) end(%08x)\n", | |
368 | fi->pc,prologue_start,prologue_end)); | |
369 | prologue_end = min(prologue_end, prologue_start + DEFAULT_SEARCH_LIMIT); | |
370 | decode_prologue (prologue_start,prologue_end,&prologue_end,&framesize, | |
371 | fi,fsr); | |
372 | return framesize; | |
373 | } | |
374 | ||
375 | /* Function: init_extra_frame_info | |
376 | This function actually figures out the frame address for a given pc and | |
377 | sp. This is tricky on the m32r because we sometimes don't use an explicit | |
378 | frame pointer, and the previous stack pointer isn't necessarily recorded | |
379 | on the stack. The only reliable way to get this info is to | |
380 | examine the prologue. */ | |
381 | ||
382 | void | |
383 | m32r_init_extra_frame_info (fi) | |
384 | struct frame_info *fi; | |
385 | { | |
386 | int reg; | |
387 | ||
388 | if (fi->next) | |
389 | fi->pc = FRAME_SAVED_PC (fi->next); | |
390 | ||
391 | memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs); | |
392 | ||
393 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) | |
394 | { | |
395 | /* We need to setup fi->frame here because run_stack_dummy gets it wrong | |
396 | by assuming it's always FP. */ | |
397 | fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM); | |
398 | fi->framesize = 0; | |
399 | return; | |
400 | } | |
401 | else | |
402 | { | |
403 | fi->using_frame_pointer = 0; | |
404 | fi->framesize = m32r_scan_prologue (fi, &fi->fsr); | |
405 | ||
406 | if (!fi->next) | |
407 | if (fi->using_frame_pointer) | |
408 | { | |
409 | fi->frame = read_register (FP_REGNUM); | |
410 | } | |
411 | else | |
412 | fi->frame = read_register (SP_REGNUM); | |
413 | else /* fi->next means this is not the innermost frame */ | |
414 | if (fi->using_frame_pointer) /* we have an FP */ | |
415 | if (fi->next->fsr.regs[FP_REGNUM] != 0) /* caller saved our FP */ | |
416 | fi->frame = read_memory_integer (fi->next->fsr.regs[FP_REGNUM], 4); | |
417 | for (reg = 0; reg < NUM_REGS; reg++) | |
418 | if (fi->fsr.regs[reg] != 0) | |
419 | fi->fsr.regs[reg] = fi->frame + fi->framesize - fi->fsr.regs[reg]; | |
420 | } | |
421 | } | |
422 | ||
423 | /* Function: mn10300_virtual_frame_pointer | |
424 | Return the register that the function uses for a frame pointer, | |
425 | plus any necessary offset to be applied to the register before | |
426 | any frame pointer offsets. */ | |
427 | ||
428 | void | |
429 | m32r_virtual_frame_pointer (pc, reg, offset) | |
430 | CORE_ADDR pc; | |
431 | long *reg; | |
432 | long *offset; | |
433 | { | |
434 | struct frame_info fi; | |
435 | ||
436 | /* Set up a dummy frame_info. */ | |
437 | fi.next = NULL; | |
438 | fi.prev = NULL; | |
439 | fi.frame = 0; | |
440 | fi.pc = pc; | |
441 | ||
442 | /* Analyze the prolog and fill in the extra info. */ | |
443 | m32r_init_extra_frame_info (&fi); | |
444 | ||
445 | ||
446 | /* Results will tell us which type of frame it uses. */ | |
447 | if (fi.using_frame_pointer) | |
448 | { | |
449 | *reg = FP_REGNUM; | |
450 | *offset = 0; | |
451 | } | |
452 | else | |
453 | { | |
454 | *reg = SP_REGNUM; | |
455 | *offset = 0; | |
456 | } | |
457 | } | |
458 | ||
459 | /* Function: find_callers_reg | |
460 | Find REGNUM on the stack. Otherwise, it's in an active register. One thing | |
461 | we might want to do here is to check REGNUM against the clobber mask, and | |
462 | somehow flag it as invalid if it isn't saved on the stack somewhere. This | |
463 | would provide a graceful failure mode when trying to get the value of | |
464 | caller-saves registers for an inner frame. */ | |
465 | ||
466 | CORE_ADDR | |
467 | m32r_find_callers_reg (fi, regnum) | |
468 | struct frame_info *fi; | |
469 | int regnum; | |
470 | { | |
471 | for (; fi; fi = fi->next) | |
472 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) | |
473 | return generic_read_register_dummy (fi->pc, fi->frame, regnum); | |
474 | else if (fi->fsr.regs[regnum] != 0) | |
475 | return read_memory_integer (fi->fsr.regs[regnum], | |
476 | REGISTER_RAW_SIZE(regnum)); | |
477 | return read_register (regnum); | |
478 | } | |
479 | ||
480 | /* Function: frame_chain | |
481 | Given a GDB frame, determine the address of the calling function's frame. | |
482 | This will be used to create a new GDB frame struct, and then | |
483 | INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame. | |
484 | For m32r, we save the frame size when we initialize the frame_info. */ | |
485 | ||
486 | CORE_ADDR | |
487 | m32r_frame_chain (fi) | |
488 | struct frame_info *fi; | |
489 | { | |
490 | CORE_ADDR fn_start, callers_pc, fp; | |
491 | ||
492 | /* is this a dummy frame? */ | |
493 | if (PC_IN_CALL_DUMMY(fi->pc, fi->frame, fi->frame)) | |
494 | return fi->frame; /* dummy frame same as caller's frame */ | |
495 | ||
496 | /* is caller-of-this a dummy frame? */ | |
497 | callers_pc = FRAME_SAVED_PC(fi); /* find out who called us: */ | |
498 | fp = m32r_find_callers_reg (fi, FP_REGNUM); | |
499 | if (PC_IN_CALL_DUMMY(callers_pc, fp, fp)) | |
500 | return fp; /* dummy frame's frame may bear no relation to ours */ | |
501 | ||
502 | if (find_pc_partial_function (fi->pc, 0, &fn_start, 0)) | |
503 | if (fn_start == entry_point_address ()) | |
504 | return 0; /* in _start fn, don't chain further */ | |
505 | if (fi->framesize == 0) | |
506 | { | |
507 | printf_filtered("cannot determine frame size @ %08x , pc(%08x)\n", | |
508 | (unsigned long) fi->frame, | |
509 | (unsigned long) fi->pc ); | |
510 | return 0; | |
511 | } | |
512 | insn_debug(("m32rx frame %08x\n",fi->frame+fi->framesize)); | |
513 | return fi->frame + fi->framesize; | |
514 | } | |
515 | ||
516 | /* Function: push_return_address (pc) | |
517 | Set up the return address for the inferior function call. | |
518 | Necessary for targets that don't actually execute a JSR/BSR instruction | |
519 | (ie. when using an empty CALL_DUMMY) */ | |
520 | ||
521 | CORE_ADDR | |
522 | m32r_push_return_address (pc, sp) | |
523 | CORE_ADDR pc; | |
524 | CORE_ADDR sp; | |
525 | { | |
526 | write_register (RP_REGNUM, CALL_DUMMY_ADDRESS ()); | |
527 | return sp; | |
528 | } | |
529 | ||
530 | ||
531 | /* Function: pop_frame | |
532 | Discard from the stack the innermost frame, | |
533 | restoring all saved registers. */ | |
534 | ||
535 | struct frame_info * | |
536 | m32r_pop_frame (frame) | |
537 | struct frame_info *frame; | |
538 | { | |
539 | int regnum; | |
540 | ||
541 | if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)) | |
542 | generic_pop_dummy_frame (); | |
543 | else | |
544 | { | |
545 | for (regnum = 0; regnum < NUM_REGS; regnum++) | |
546 | if (frame->fsr.regs[regnum] != 0) | |
547 | write_register (regnum, | |
548 | read_memory_integer (frame->fsr.regs[regnum], 4)); | |
549 | ||
550 | write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); | |
551 | write_register (SP_REGNUM, read_register (FP_REGNUM)); | |
552 | if (read_register (PSW_REGNUM) & 0x80) | |
553 | write_register (SPU_REGNUM, read_register (SP_REGNUM)); | |
554 | else | |
555 | write_register (SPI_REGNUM, read_register (SP_REGNUM)); | |
556 | } | |
557 | flush_cached_frames (); | |
558 | return NULL; | |
559 | } | |
560 | ||
561 | /* Function: frame_saved_pc | |
562 | Find the caller of this frame. We do this by seeing if RP_REGNUM is saved | |
563 | in the stack anywhere, otherwise we get it from the registers. */ | |
564 | ||
565 | CORE_ADDR | |
566 | m32r_frame_saved_pc (fi) | |
567 | struct frame_info *fi; | |
568 | { | |
569 | if (PC_IN_CALL_DUMMY(fi->pc, fi->frame, fi->frame)) | |
570 | return generic_read_register_dummy(fi->pc, fi->frame, PC_REGNUM); | |
571 | else | |
572 | return m32r_find_callers_reg (fi, RP_REGNUM); | |
573 | } | |
574 | ||
575 | /* Function: push_arguments | |
576 | Setup the function arguments for calling a function in the inferior. | |
577 | ||
578 | On the Mitsubishi M32R architecture, there are four registers (R0 to R3) | |
579 | which are dedicated for passing function arguments. Up to the first | |
580 | four arguments (depending on size) may go into these registers. | |
581 | The rest go on the stack. | |
582 | ||
583 | Arguments that are smaller than 4 bytes will still take up a whole | |
584 | register or a whole 32-bit word on the stack, and will be | |
585 | right-justified in the register or the stack word. This includes | |
586 | chars, shorts, and small aggregate types. | |
587 | ||
588 | Arguments of 8 bytes size are split between two registers, if | |
589 | available. If only one register is available, the argument will | |
590 | be split between the register and the stack. Otherwise it is | |
591 | passed entirely on the stack. Aggregate types with sizes between | |
592 | 4 and 8 bytes are passed entirely on the stack, and are left-justified | |
593 | within the double-word (as opposed to aggregates smaller than 4 bytes | |
594 | which are right-justified). | |
595 | ||
596 | Aggregates of greater than 8 bytes are first copied onto the stack, | |
597 | and then a pointer to the copy is passed in the place of the normal | |
598 | argument (either in a register if available, or on the stack). | |
599 | ||
600 | Functions that must return an aggregate type can return it in the | |
601 | normal return value registers (R0 and R1) if its size is 8 bytes or | |
602 | less. For larger return values, the caller must allocate space for | |
603 | the callee to copy the return value to. A pointer to this space is | |
604 | passed as an implicit first argument, always in R0. */ | |
605 | ||
606 | CORE_ADDR | |
607 | m32r_push_arguments (nargs, args, sp, struct_return, struct_addr) | |
608 | int nargs; | |
609 | value_ptr *args; | |
610 | CORE_ADDR sp; | |
611 | unsigned char struct_return; | |
612 | CORE_ADDR struct_addr; | |
613 | { | |
614 | int stack_offset, stack_alloc; | |
615 | int argreg; | |
616 | int argnum; | |
617 | struct type *type; | |
618 | CORE_ADDR regval; | |
619 | char *val; | |
620 | char valbuf[4]; | |
621 | int len; | |
622 | int odd_sized_struct; | |
623 | ||
624 | /* first force sp to a 4-byte alignment */ | |
625 | sp = sp & ~3; | |
626 | ||
627 | argreg = ARG0_REGNUM; | |
628 | /* The "struct return pointer" pseudo-argument goes in R0 */ | |
629 | if (struct_return) | |
630 | write_register (argreg++, struct_addr); | |
631 | ||
632 | /* Now make sure there's space on the stack */ | |
633 | for (argnum = 0, stack_alloc = 0; | |
634 | argnum < nargs; argnum++) | |
635 | stack_alloc += ((TYPE_LENGTH(VALUE_TYPE(args[argnum])) + 3) & ~3); | |
636 | sp -= stack_alloc; /* make room on stack for args */ | |
637 | ||
638 | ||
639 | /* Now load as many as possible of the first arguments into | |
640 | registers, and push the rest onto the stack. There are 16 bytes | |
641 | in four registers available. Loop thru args from first to last. */ | |
642 | ||
643 | argreg = ARG0_REGNUM; | |
644 | for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++) | |
645 | { | |
646 | type = VALUE_TYPE (args[argnum]); | |
647 | len = TYPE_LENGTH (type); | |
648 | memset(valbuf, 0, sizeof(valbuf)); | |
649 | if (len < 4) | |
650 | { /* value gets right-justified in the register or stack word */ | |
651 | memcpy(valbuf + (4 - len), | |
652 | (char *) VALUE_CONTENTS (args[argnum]), len); | |
653 | val = valbuf; | |
654 | } | |
655 | else | |
656 | val = (char *) VALUE_CONTENTS (args[argnum]); | |
657 | ||
658 | if (len > 4 && (len & 3) != 0) | |
659 | odd_sized_struct = 1; /* such structs go entirely on stack */ | |
660 | else | |
661 | odd_sized_struct = 0; | |
662 | while (len > 0) | |
663 | { | |
664 | if (argreg > ARGLAST_REGNUM || odd_sized_struct) | |
665 | { /* must go on the stack */ | |
666 | write_memory (sp + stack_offset, val, 4); | |
667 | stack_offset += 4; | |
668 | } | |
669 | /* NOTE WELL!!!!! This is not an "else if" clause!!! | |
670 | That's because some *&^%$ things get passed on the stack | |
671 | AND in the registers! */ | |
672 | if (argreg <= ARGLAST_REGNUM) | |
673 | { /* there's room in a register */ | |
674 | regval = extract_address (val, REGISTER_RAW_SIZE(argreg)); | |
675 | write_register (argreg++, regval); | |
676 | } | |
677 | /* Store the value 4 bytes at a time. This means that things | |
678 | larger than 4 bytes may go partly in registers and partly | |
679 | on the stack. */ | |
680 | len -= REGISTER_RAW_SIZE(argreg); | |
681 | val += REGISTER_RAW_SIZE(argreg); | |
682 | } | |
683 | } | |
684 | return sp; | |
685 | } | |
686 | ||
687 | /* Function: fix_call_dummy | |
688 | If there is real CALL_DUMMY code (eg. on the stack), this function | |
689 | has the responsability to insert the address of the actual code that | |
690 | is the target of the target function call. */ | |
691 | ||
692 | void | |
693 | m32r_fix_call_dummy (dummy, pc, fun, nargs, args, type, gcc_p) | |
694 | char *dummy; | |
695 | CORE_ADDR pc; | |
696 | CORE_ADDR fun; | |
697 | int nargs; | |
698 | value_ptr *args; | |
699 | struct type *type; | |
700 | int gcc_p; | |
701 | { | |
702 | /* ld24 r8, <(imm24) fun> */ | |
703 | *(unsigned long *) (dummy) = (fun & 0x00ffffff) | 0xe8000000; | |
704 | } | |
705 | ||
c906108c SS |
706 | |
707 | /* Function: m32r_write_sp | |
708 | Because SP is really a read-only register that mirrors either SPU or SPI, | |
709 | we must actually write one of those two as well, depending on PSW. */ | |
710 | ||
711 | void | |
712 | m32r_write_sp (val) | |
713 | CORE_ADDR val; | |
714 | { | |
715 | unsigned long psw = read_register (PSW_REGNUM); | |
716 | ||
717 | if (psw & 0x80) /* stack mode: user or interrupt */ | |
718 | write_register (SPU_REGNUM, val); | |
719 | else | |
720 | write_register (SPI_REGNUM, val); | |
721 | write_register (SP_REGNUM, val); | |
722 | } | |
723 | ||
724 | void | |
725 | _initialize_m32r_tdep () | |
726 | { | |
727 | tm_print_insn = print_insn_m32r; | |
728 | } | |
729 |