Commit | Line | Data |
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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 | ||
c5aa993b | 4 | This file is part of GDB. |
c906108c | 5 | |
c5aa993b JM |
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. | |
c906108c | 10 | |
c5aa993b JM |
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. | |
c906108c | 15 | |
c5aa993b JM |
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, | |
19 | Boston, MA 02111-1307, USA. */ | |
c906108c SS |
20 | |
21 | #include "defs.h" | |
22 | #include "frame.h" | |
23 | #include "inferior.h" | |
24 | #include "obstack.h" | |
25 | #include "target.h" | |
26 | #include "value.h" | |
27 | #include "bfd.h" | |
28 | #include "gdb_string.h" | |
29 | #include "gdbcore.h" | |
30 | #include "symfile.h" | |
31 | ||
32 | /* Function: m32r_use_struct_convention | |
33 | Return nonzero if call_function should allocate stack space for a | |
34 | struct return? */ | |
35 | int | |
fba45db2 | 36 | m32r_use_struct_convention (int gcc_p, struct type *type) |
c906108c SS |
37 | { |
38 | return (TYPE_LENGTH (type) > 8); | |
39 | } | |
40 | ||
41 | /* Function: frame_find_saved_regs | |
42 | Return the frame_saved_regs structure for the frame. | |
43 | Doesn't really work for dummy frames, but it does pass back | |
44 | an empty frame_saved_regs, so I guess that's better than total failure */ | |
45 | ||
c5aa993b | 46 | void |
fba45db2 KB |
47 | m32r_frame_find_saved_regs (struct frame_info *fi, |
48 | struct frame_saved_regs *regaddr) | |
c906108c | 49 | { |
c5aa993b | 50 | memcpy (regaddr, &fi->fsr, sizeof (struct frame_saved_regs)); |
c906108c SS |
51 | } |
52 | ||
53 | /* Turn this on if you want to see just how much instruction decoding | |
54 | if being done, its quite a lot | |
c5aa993b | 55 | */ |
c906108c | 56 | #if 0 |
c5aa993b JM |
57 | static void |
58 | dump_insn (char *commnt, CORE_ADDR pc, int insn) | |
c906108c | 59 | { |
c5aa993b JM |
60 | printf_filtered (" %s %08x %08x ", |
61 | commnt, (unsigned int) pc, (unsigned int) insn); | |
62 | (*tm_print_insn) (pc, &tm_print_insn_info); | |
63 | printf_filtered ("\n"); | |
c906108c SS |
64 | } |
65 | #define insn_debug(args) { printf_filtered args; } | |
66 | #else | |
67 | #define dump_insn(a,b,c) {} | |
68 | #define insn_debug(args) {} | |
69 | #endif | |
70 | ||
c5aa993b | 71 | #define DEFAULT_SEARCH_LIMIT 44 |
c906108c SS |
72 | |
73 | /* Function: scan_prologue | |
74 | This function decodes the target function prologue to determine | |
75 | 1) the size of the stack frame, and 2) which registers are saved on it. | |
76 | It saves the offsets of saved regs in the frame_saved_regs argument, | |
77 | and returns the frame size. */ | |
78 | ||
79 | /* | |
c5aa993b JM |
80 | The sequence it currently generates is: |
81 | ||
82 | if (varargs function) { ddi sp,#n } | |
83 | push registers | |
84 | if (additional stack <= 256) { addi sp,#-stack } | |
85 | else if (additional stack < 65k) { add3 sp,sp,#-stack | |
86 | ||
87 | } else if (additional stack) { | |
88 | seth sp,#(stack & 0xffff0000) | |
89 | or3 sp,sp,#(stack & 0x0000ffff) | |
90 | sub sp,r4 | |
91 | } | |
92 | if (frame pointer) { | |
93 | mv sp,fp | |
94 | } | |
c906108c | 95 | |
c5aa993b JM |
96 | These instructions are scheduled like everything else, so you should stop at |
97 | the first branch instruction. | |
98 | ||
99 | */ | |
c906108c SS |
100 | |
101 | /* This is required by skip prologue and by m32r_init_extra_frame_info. | |
102 | The results of decoding a prologue should be cached because this | |
103 | thrashing is getting nuts. | |
104 | I am thinking of making a container class with two indexes, name and | |
105 | address. It may be better to extend the symbol table. | |
c5aa993b | 106 | */ |
c906108c | 107 | |
c5aa993b | 108 | static void |
fba45db2 KB |
109 | decode_prologue (CORE_ADDR start_pc, CORE_ADDR scan_limit, CORE_ADDR *pl_endptr, /* var parameter */ |
110 | unsigned long *framelength, struct frame_info *fi, | |
111 | struct frame_saved_regs *fsr) | |
c906108c SS |
112 | { |
113 | unsigned long framesize; | |
114 | int insn; | |
115 | int op1; | |
116 | int maybe_one_more = 0; | |
117 | CORE_ADDR after_prologue = 0; | |
118 | CORE_ADDR after_stack_adjust = 0; | |
119 | CORE_ADDR current_pc; | |
120 | ||
121 | ||
122 | framesize = 0; | |
123 | after_prologue = 0; | |
c5aa993b | 124 | insn_debug (("rd prolog l(%d)\n", scan_limit - current_pc)); |
c906108c SS |
125 | |
126 | for (current_pc = start_pc; current_pc < scan_limit; current_pc += 2) | |
127 | { | |
128 | ||
129 | insn = read_memory_unsigned_integer (current_pc, 2); | |
c5aa993b JM |
130 | dump_insn ("insn-1", current_pc, insn); /* MTZ */ |
131 | ||
132 | /* If this is a 32 bit instruction, we dont want to examine its | |
133 | immediate data as though it were an instruction */ | |
c906108c | 134 | if (current_pc & 0x02) |
c5aa993b | 135 | { /* Clear the parallel execution bit from 16 bit instruction */ |
c906108c | 136 | if (maybe_one_more) |
c5aa993b JM |
137 | { /* The last instruction was a branch, usually terminates |
138 | the series, but if this is a parallel instruction, | |
139 | it may be a stack framing instruction */ | |
140 | if (!(insn & 0x8000)) | |
141 | { | |
142 | insn_debug (("Really done")); | |
143 | break; /* nope, we are really done */ | |
c906108c SS |
144 | } |
145 | } | |
c5aa993b | 146 | insn &= 0x7fff; /* decode this instruction further */ |
c906108c SS |
147 | } |
148 | else | |
149 | { | |
c5aa993b JM |
150 | if (maybe_one_more) |
151 | break; /* This isnt the one more */ | |
c906108c SS |
152 | if (insn & 0x8000) |
153 | { | |
c5aa993b | 154 | insn_debug (("32 bit insn\n")); |
c906108c | 155 | if (current_pc == scan_limit) |
c5aa993b JM |
156 | scan_limit += 2; /* extend the search */ |
157 | current_pc += 2; /* skip the immediate data */ | |
158 | if (insn == 0x8faf) /* add3 sp, sp, xxxx */ | |
c906108c | 159 | /* add 16 bit sign-extended offset */ |
c5aa993b JM |
160 | { |
161 | insn_debug (("stack increment\n")); | |
162 | framesize += -((short) read_memory_unsigned_integer (current_pc, 2)); | |
c906108c SS |
163 | } |
164 | else | |
165 | { | |
c5aa993b JM |
166 | if (((insn >> 8) == 0xe4) && /* ld24 r4, xxxxxx; sub sp, r4 */ |
167 | read_memory_unsigned_integer (current_pc + 2, 2) == 0x0f24) | |
168 | { /* subtract 24 bit sign-extended negative-offset */ | |
169 | dump_insn ("insn-2", current_pc + 2, insn); | |
c906108c | 170 | insn = read_memory_unsigned_integer (current_pc - 2, 4); |
c5aa993b | 171 | dump_insn ("insn-3(l4)", current_pc - 2, insn); |
c906108c | 172 | if (insn & 0x00800000) /* sign extend */ |
c5aa993b | 173 | insn |= 0xff000000; /* negative */ |
c906108c | 174 | else |
c5aa993b | 175 | insn &= 0x00ffffff; /* positive */ |
c906108c SS |
176 | framesize += insn; |
177 | } | |
178 | } | |
179 | after_prologue = current_pc; | |
180 | continue; | |
181 | } | |
182 | } | |
c5aa993b JM |
183 | op1 = insn & 0xf000; /* isolate just the first nibble */ |
184 | ||
c906108c | 185 | if ((insn & 0xf0ff) == 0x207f) |
c5aa993b | 186 | { /* st reg, @-sp */ |
c906108c | 187 | int regno; |
c5aa993b JM |
188 | insn_debug (("push\n")); |
189 | #if 0 /* No, PUSH FP is not an indication that we will use a frame pointer. */ | |
190 | if (((insn & 0xffff) == 0x2d7f) && fi) | |
c906108c SS |
191 | fi->using_frame_pointer = 1; |
192 | #endif | |
c5aa993b JM |
193 | framesize += 4; |
194 | #if 0 | |
c906108c SS |
195 | /* Why should we increase the scan limit, just because we did a push? |
196 | And if there is a reason, surely we would only want to do it if we | |
197 | had already reached the scan limit... */ | |
198 | if (current_pc == scan_limit) | |
199 | scan_limit += 2; | |
200 | #endif | |
201 | regno = ((insn >> 8) & 0xf); | |
c5aa993b | 202 | if (fsr) /* save_regs offset */ |
c906108c SS |
203 | fsr->regs[regno] = framesize; |
204 | after_prologue = 0; | |
c5aa993b | 205 | continue; |
c906108c | 206 | } |
c5aa993b | 207 | if ((insn >> 8) == 0x4f) /* addi sp, xx */ |
c906108c SS |
208 | /* add 8 bit sign-extended offset */ |
209 | { | |
210 | int stack_adjust = (char) (insn & 0xff); | |
211 | ||
212 | /* there are probably two of these stack adjustments: | |
213 | 1) A negative one in the prologue, and | |
214 | 2) A positive one in the epilogue. | |
215 | We are only interested in the first one. */ | |
216 | ||
217 | if (stack_adjust < 0) | |
218 | { | |
219 | framesize -= stack_adjust; | |
220 | after_prologue = 0; | |
221 | /* A frameless function may have no "mv fp, sp". | |
c5aa993b | 222 | In that case, this is the end of the prologue. */ |
c906108c SS |
223 | after_stack_adjust = current_pc + 2; |
224 | } | |
225 | continue; | |
226 | } | |
c5aa993b JM |
227 | if (insn == 0x1d8f) |
228 | { /* mv fp, sp */ | |
229 | if (fi) | |
230 | fi->using_frame_pointer = 1; /* fp is now valid */ | |
231 | insn_debug (("done fp found\n")); | |
232 | after_prologue = current_pc + 2; | |
233 | break; /* end of stack adjustments */ | |
234 | } | |
235 | if (insn == 0x7000) /* Nop looks like a branch, continue explicitly */ | |
236 | { | |
237 | insn_debug (("nop\n")); | |
238 | after_prologue = current_pc + 2; | |
239 | continue; /* nop occurs between pushes */ | |
c906108c SS |
240 | } |
241 | /* End of prolog if any of these are branch instructions */ | |
242 | if ((op1 == 0x7000) | |
c5aa993b | 243 | || (op1 == 0xb000) |
cff3e48b | 244 | || (op1 == 0xf000)) |
c906108c SS |
245 | { |
246 | after_prologue = current_pc; | |
c5aa993b | 247 | insn_debug (("Done: branch\n")); |
c906108c SS |
248 | maybe_one_more = 1; |
249 | continue; | |
250 | } | |
251 | /* Some of the branch instructions are mixed with other types */ | |
252 | if (op1 == 0x1000) | |
c5aa993b JM |
253 | { |
254 | int subop = insn & 0x0ff0; | |
c906108c | 255 | if ((subop == 0x0ec0) || (subop == 0x0fc0)) |
c5aa993b JM |
256 | { |
257 | insn_debug (("done: jmp\n")); | |
c906108c SS |
258 | after_prologue = current_pc; |
259 | maybe_one_more = 1; | |
c5aa993b | 260 | continue; /* jmp , jl */ |
c906108c SS |
261 | } |
262 | } | |
263 | } | |
264 | ||
265 | if (current_pc >= scan_limit) | |
266 | { | |
c5aa993b | 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; | |
c5aa993b | 286 | } |
c906108c SS |
287 | return; |
288 | } | |
c5aa993b | 289 | if (after_prologue == 0) |
c906108c SS |
290 | after_prologue = current_pc; |
291 | ||
c5aa993b JM |
292 | insn_debug ((" framesize %d, firstline %08x\n", framesize, after_prologue)); |
293 | if (framelength) | |
c906108c | 294 | *framelength = framesize; |
c5aa993b | 295 | if (pl_endptr) |
c906108c | 296 | *pl_endptr = after_prologue; |
c5aa993b | 297 | } /* decode_prologue */ |
c906108c SS |
298 | |
299 | /* Function: skip_prologue | |
300 | Find end of function prologue */ | |
301 | ||
302 | CORE_ADDR | |
fba45db2 | 303 | m32r_skip_prologue (CORE_ADDR pc) |
c906108c SS |
304 | { |
305 | CORE_ADDR func_addr, func_end; | |
306 | struct symtab_and_line sal; | |
307 | ||
308 | /* See what the symbol table says */ | |
309 | ||
310 | if (find_pc_partial_function (pc, NULL, &func_addr, &func_end)) | |
311 | { | |
312 | sal = find_pc_line (func_addr, 0); | |
313 | ||
314 | if (sal.line != 0 && sal.end <= func_end) | |
315 | { | |
c5aa993b JM |
316 | |
317 | insn_debug (("BP after prologue %08x\n", sal.end)); | |
c906108c SS |
318 | func_end = sal.end; |
319 | } | |
320 | else | |
321 | /* Either there's no line info, or the line after the prologue is after | |
322 | the end of the function. In this case, there probably isn't a | |
323 | prologue. */ | |
324 | { | |
c5aa993b JM |
325 | insn_debug (("No line info, line(%x) sal_end(%x) funcend(%x)\n", |
326 | sal.line, sal.end, func_end)); | |
327 | func_end = min (func_end, func_addr + DEFAULT_SEARCH_LIMIT); | |
c906108c SS |
328 | } |
329 | } | |
c5aa993b | 330 | else |
c906108c SS |
331 | func_end = pc + DEFAULT_SEARCH_LIMIT; |
332 | decode_prologue (pc, func_end, &sal.end, 0, 0, 0); | |
333 | return sal.end; | |
334 | } | |
335 | ||
336 | static unsigned long | |
fba45db2 | 337 | m32r_scan_prologue (struct frame_info *fi, struct frame_saved_regs *fsr) |
c906108c SS |
338 | { |
339 | struct symtab_and_line sal; | |
340 | CORE_ADDR prologue_start, prologue_end, current_pc; | |
cff3e48b | 341 | unsigned long framesize = 0; |
c906108c SS |
342 | |
343 | /* this code essentially duplicates skip_prologue, | |
344 | but we need the start address below. */ | |
345 | ||
346 | if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end)) | |
347 | { | |
348 | sal = find_pc_line (prologue_start, 0); | |
349 | ||
c5aa993b | 350 | if (sal.line == 0) /* no line info, use current PC */ |
c906108c SS |
351 | if (prologue_start == entry_point_address ()) |
352 | return 0; | |
353 | } | |
354 | else | |
355 | { | |
356 | prologue_start = fi->pc; | |
c5aa993b JM |
357 | prologue_end = prologue_start + 48; /* We're in the boondocks: |
358 | allow for 16 pushes, an add, | |
359 | and "mv fp,sp" */ | |
c906108c SS |
360 | } |
361 | #if 0 | |
362 | prologue_end = min (prologue_end, fi->pc); | |
363 | #endif | |
c5aa993b JM |
364 | insn_debug (("fipc(%08x) start(%08x) end(%08x)\n", |
365 | fi->pc, prologue_start, prologue_end)); | |
366 | prologue_end = min (prologue_end, prologue_start + DEFAULT_SEARCH_LIMIT); | |
367 | decode_prologue (prologue_start, prologue_end, &prologue_end, &framesize, | |
368 | fi, fsr); | |
c906108c SS |
369 | return framesize; |
370 | } | |
371 | ||
372 | /* Function: init_extra_frame_info | |
373 | This function actually figures out the frame address for a given pc and | |
374 | sp. This is tricky on the m32r because we sometimes don't use an explicit | |
375 | frame pointer, and the previous stack pointer isn't necessarily recorded | |
376 | on the stack. The only reliable way to get this info is to | |
377 | examine the prologue. */ | |
378 | ||
379 | void | |
fba45db2 | 380 | m32r_init_extra_frame_info (struct frame_info *fi) |
c906108c SS |
381 | { |
382 | int reg; | |
383 | ||
384 | if (fi->next) | |
385 | fi->pc = FRAME_SAVED_PC (fi->next); | |
386 | ||
387 | memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs); | |
388 | ||
389 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) | |
390 | { | |
391 | /* We need to setup fi->frame here because run_stack_dummy gets it wrong | |
c5aa993b | 392 | by assuming it's always FP. */ |
c906108c SS |
393 | fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM); |
394 | fi->framesize = 0; | |
395 | return; | |
396 | } | |
c5aa993b | 397 | else |
c906108c SS |
398 | { |
399 | fi->using_frame_pointer = 0; | |
400 | fi->framesize = m32r_scan_prologue (fi, &fi->fsr); | |
401 | ||
402 | if (!fi->next) | |
403 | if (fi->using_frame_pointer) | |
404 | { | |
405 | fi->frame = read_register (FP_REGNUM); | |
406 | } | |
407 | else | |
408 | fi->frame = read_register (SP_REGNUM); | |
c5aa993b JM |
409 | else |
410 | /* fi->next means this is not the innermost frame */ if (fi->using_frame_pointer) | |
411 | /* we have an FP */ | |
412 | if (fi->next->fsr.regs[FP_REGNUM] != 0) /* caller saved our FP */ | |
413 | fi->frame = read_memory_integer (fi->next->fsr.regs[FP_REGNUM], 4); | |
c906108c SS |
414 | for (reg = 0; reg < NUM_REGS; reg++) |
415 | if (fi->fsr.regs[reg] != 0) | |
416 | fi->fsr.regs[reg] = fi->frame + fi->framesize - fi->fsr.regs[reg]; | |
417 | } | |
418 | } | |
419 | ||
420 | /* Function: mn10300_virtual_frame_pointer | |
421 | Return the register that the function uses for a frame pointer, | |
422 | plus any necessary offset to be applied to the register before | |
423 | any frame pointer offsets. */ | |
424 | ||
425 | void | |
fba45db2 | 426 | m32r_virtual_frame_pointer (CORE_ADDR pc, long *reg, long *offset) |
c906108c SS |
427 | { |
428 | struct frame_info fi; | |
429 | ||
430 | /* Set up a dummy frame_info. */ | |
431 | fi.next = NULL; | |
432 | fi.prev = NULL; | |
433 | fi.frame = 0; | |
434 | fi.pc = pc; | |
435 | ||
436 | /* Analyze the prolog and fill in the extra info. */ | |
437 | m32r_init_extra_frame_info (&fi); | |
438 | ||
439 | ||
440 | /* Results will tell us which type of frame it uses. */ | |
441 | if (fi.using_frame_pointer) | |
442 | { | |
c5aa993b | 443 | *reg = FP_REGNUM; |
c906108c SS |
444 | *offset = 0; |
445 | } | |
446 | else | |
447 | { | |
c5aa993b | 448 | *reg = SP_REGNUM; |
c906108c SS |
449 | *offset = 0; |
450 | } | |
451 | } | |
452 | ||
453 | /* Function: find_callers_reg | |
454 | Find REGNUM on the stack. Otherwise, it's in an active register. One thing | |
455 | we might want to do here is to check REGNUM against the clobber mask, and | |
456 | somehow flag it as invalid if it isn't saved on the stack somewhere. This | |
457 | would provide a graceful failure mode when trying to get the value of | |
458 | caller-saves registers for an inner frame. */ | |
459 | ||
460 | CORE_ADDR | |
fba45db2 | 461 | m32r_find_callers_reg (struct frame_info *fi, int regnum) |
c906108c SS |
462 | { |
463 | for (; fi; fi = fi->next) | |
464 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) | |
465 | return generic_read_register_dummy (fi->pc, fi->frame, regnum); | |
466 | else if (fi->fsr.regs[regnum] != 0) | |
c5aa993b JM |
467 | return read_memory_integer (fi->fsr.regs[regnum], |
468 | REGISTER_RAW_SIZE (regnum)); | |
c906108c SS |
469 | return read_register (regnum); |
470 | } | |
471 | ||
472 | /* Function: frame_chain | |
473 | Given a GDB frame, determine the address of the calling function's frame. | |
474 | This will be used to create a new GDB frame struct, and then | |
475 | INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame. | |
476 | For m32r, we save the frame size when we initialize the frame_info. */ | |
477 | ||
478 | CORE_ADDR | |
fba45db2 | 479 | m32r_frame_chain (struct frame_info *fi) |
c906108c SS |
480 | { |
481 | CORE_ADDR fn_start, callers_pc, fp; | |
482 | ||
483 | /* is this a dummy frame? */ | |
c5aa993b JM |
484 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
485 | return fi->frame; /* dummy frame same as caller's frame */ | |
c906108c SS |
486 | |
487 | /* is caller-of-this a dummy frame? */ | |
c5aa993b | 488 | callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */ |
c906108c | 489 | fp = m32r_find_callers_reg (fi, FP_REGNUM); |
c5aa993b JM |
490 | if (PC_IN_CALL_DUMMY (callers_pc, fp, fp)) |
491 | return fp; /* dummy frame's frame may bear no relation to ours */ | |
c906108c SS |
492 | |
493 | if (find_pc_partial_function (fi->pc, 0, &fn_start, 0)) | |
494 | if (fn_start == entry_point_address ()) | |
c5aa993b | 495 | return 0; /* in _start fn, don't chain further */ |
c906108c SS |
496 | if (fi->framesize == 0) |
497 | { | |
d4f3574e SS |
498 | printf_filtered ("cannot determine frame size @ %s , pc(%s)\n", |
499 | paddr (fi->frame), | |
500 | paddr (fi->pc)); | |
c906108c SS |
501 | return 0; |
502 | } | |
c5aa993b | 503 | insn_debug (("m32rx frame %08x\n", fi->frame + fi->framesize)); |
c906108c SS |
504 | return fi->frame + fi->framesize; |
505 | } | |
506 | ||
507 | /* Function: push_return_address (pc) | |
508 | Set up the return address for the inferior function call. | |
509 | Necessary for targets that don't actually execute a JSR/BSR instruction | |
510 | (ie. when using an empty CALL_DUMMY) */ | |
511 | ||
512 | CORE_ADDR | |
fba45db2 | 513 | m32r_push_return_address (CORE_ADDR pc, CORE_ADDR sp) |
c906108c SS |
514 | { |
515 | write_register (RP_REGNUM, CALL_DUMMY_ADDRESS ()); | |
516 | return sp; | |
517 | } | |
518 | ||
519 | ||
520 | /* Function: pop_frame | |
521 | Discard from the stack the innermost frame, | |
522 | restoring all saved registers. */ | |
523 | ||
524 | struct frame_info * | |
fba45db2 | 525 | m32r_pop_frame (struct frame_info *frame) |
c906108c SS |
526 | { |
527 | int regnum; | |
528 | ||
529 | if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)) | |
530 | generic_pop_dummy_frame (); | |
531 | else | |
532 | { | |
533 | for (regnum = 0; regnum < NUM_REGS; regnum++) | |
534 | if (frame->fsr.regs[regnum] != 0) | |
c5aa993b | 535 | write_register (regnum, |
c906108c SS |
536 | read_memory_integer (frame->fsr.regs[regnum], 4)); |
537 | ||
538 | write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); | |
539 | write_register (SP_REGNUM, read_register (FP_REGNUM)); | |
540 | if (read_register (PSW_REGNUM) & 0x80) | |
541 | write_register (SPU_REGNUM, read_register (SP_REGNUM)); | |
542 | else | |
543 | write_register (SPI_REGNUM, read_register (SP_REGNUM)); | |
544 | } | |
545 | flush_cached_frames (); | |
546 | return NULL; | |
547 | } | |
548 | ||
549 | /* Function: frame_saved_pc | |
550 | Find the caller of this frame. We do this by seeing if RP_REGNUM is saved | |
551 | in the stack anywhere, otherwise we get it from the registers. */ | |
552 | ||
553 | CORE_ADDR | |
fba45db2 | 554 | m32r_frame_saved_pc (struct frame_info *fi) |
c906108c | 555 | { |
c5aa993b JM |
556 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
557 | return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM); | |
c906108c SS |
558 | else |
559 | return m32r_find_callers_reg (fi, RP_REGNUM); | |
560 | } | |
561 | ||
562 | /* Function: push_arguments | |
563 | Setup the function arguments for calling a function in the inferior. | |
564 | ||
565 | On the Mitsubishi M32R architecture, there are four registers (R0 to R3) | |
566 | which are dedicated for passing function arguments. Up to the first | |
567 | four arguments (depending on size) may go into these registers. | |
568 | The rest go on the stack. | |
569 | ||
570 | Arguments that are smaller than 4 bytes will still take up a whole | |
571 | register or a whole 32-bit word on the stack, and will be | |
572 | right-justified in the register or the stack word. This includes | |
573 | chars, shorts, and small aggregate types. | |
c5aa993b | 574 | |
c906108c SS |
575 | Arguments of 8 bytes size are split between two registers, if |
576 | available. If only one register is available, the argument will | |
577 | be split between the register and the stack. Otherwise it is | |
578 | passed entirely on the stack. Aggregate types with sizes between | |
579 | 4 and 8 bytes are passed entirely on the stack, and are left-justified | |
580 | within the double-word (as opposed to aggregates smaller than 4 bytes | |
581 | which are right-justified). | |
582 | ||
583 | Aggregates of greater than 8 bytes are first copied onto the stack, | |
584 | and then a pointer to the copy is passed in the place of the normal | |
585 | argument (either in a register if available, or on the stack). | |
586 | ||
587 | Functions that must return an aggregate type can return it in the | |
588 | normal return value registers (R0 and R1) if its size is 8 bytes or | |
589 | less. For larger return values, the caller must allocate space for | |
590 | the callee to copy the return value to. A pointer to this space is | |
591 | passed as an implicit first argument, always in R0. */ | |
592 | ||
593 | CORE_ADDR | |
fba45db2 KB |
594 | m32r_push_arguments (int nargs, value_ptr *args, CORE_ADDR sp, |
595 | unsigned char struct_return, CORE_ADDR struct_addr) | |
c906108c SS |
596 | { |
597 | int stack_offset, stack_alloc; | |
598 | int argreg; | |
599 | int argnum; | |
600 | struct type *type; | |
601 | CORE_ADDR regval; | |
602 | char *val; | |
603 | char valbuf[4]; | |
604 | int len; | |
605 | int odd_sized_struct; | |
606 | ||
607 | /* first force sp to a 4-byte alignment */ | |
608 | sp = sp & ~3; | |
609 | ||
c5aa993b | 610 | argreg = ARG0_REGNUM; |
c906108c SS |
611 | /* The "struct return pointer" pseudo-argument goes in R0 */ |
612 | if (struct_return) | |
c5aa993b JM |
613 | write_register (argreg++, struct_addr); |
614 | ||
c906108c SS |
615 | /* Now make sure there's space on the stack */ |
616 | for (argnum = 0, stack_alloc = 0; | |
617 | argnum < nargs; argnum++) | |
c5aa993b JM |
618 | stack_alloc += ((TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3); |
619 | sp -= stack_alloc; /* make room on stack for args */ | |
620 | ||
621 | ||
c906108c SS |
622 | /* Now load as many as possible of the first arguments into |
623 | registers, and push the rest onto the stack. There are 16 bytes | |
624 | in four registers available. Loop thru args from first to last. */ | |
c5aa993b | 625 | |
c906108c SS |
626 | argreg = ARG0_REGNUM; |
627 | for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++) | |
628 | { | |
629 | type = VALUE_TYPE (args[argnum]); | |
c5aa993b JM |
630 | len = TYPE_LENGTH (type); |
631 | memset (valbuf, 0, sizeof (valbuf)); | |
c906108c | 632 | if (len < 4) |
c5aa993b JM |
633 | { /* value gets right-justified in the register or stack word */ |
634 | memcpy (valbuf + (4 - len), | |
635 | (char *) VALUE_CONTENTS (args[argnum]), len); | |
636 | val = valbuf; | |
637 | } | |
c906108c | 638 | else |
c5aa993b JM |
639 | val = (char *) VALUE_CONTENTS (args[argnum]); |
640 | ||
c906108c | 641 | if (len > 4 && (len & 3) != 0) |
c5aa993b | 642 | odd_sized_struct = 1; /* such structs go entirely on stack */ |
c906108c | 643 | else |
c5aa993b | 644 | odd_sized_struct = 0; |
c906108c | 645 | while (len > 0) |
c5aa993b JM |
646 | { |
647 | if (argreg > ARGLAST_REGNUM || odd_sized_struct) | |
648 | { /* must go on the stack */ | |
649 | write_memory (sp + stack_offset, val, 4); | |
650 | stack_offset += 4; | |
651 | } | |
652 | /* NOTE WELL!!!!! This is not an "else if" clause!!! | |
653 | That's because some *&^%$ things get passed on the stack | |
654 | AND in the registers! */ | |
655 | if (argreg <= ARGLAST_REGNUM) | |
656 | { /* there's room in a register */ | |
657 | regval = extract_address (val, REGISTER_RAW_SIZE (argreg)); | |
658 | write_register (argreg++, regval); | |
659 | } | |
660 | /* Store the value 4 bytes at a time. This means that things | |
661 | larger than 4 bytes may go partly in registers and partly | |
662 | on the stack. */ | |
663 | len -= REGISTER_RAW_SIZE (argreg); | |
664 | val += REGISTER_RAW_SIZE (argreg); | |
665 | } | |
c906108c SS |
666 | } |
667 | return sp; | |
668 | } | |
669 | ||
670 | /* Function: fix_call_dummy | |
671 | If there is real CALL_DUMMY code (eg. on the stack), this function | |
672 | has the responsability to insert the address of the actual code that | |
673 | is the target of the target function call. */ | |
674 | ||
675 | void | |
fba45db2 KB |
676 | m32r_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs, |
677 | value_ptr *args, struct type *type, int gcc_p) | |
c906108c SS |
678 | { |
679 | /* ld24 r8, <(imm24) fun> */ | |
680 | *(unsigned long *) (dummy) = (fun & 0x00ffffff) | 0xe8000000; | |
681 | } | |
682 | ||
c906108c SS |
683 | |
684 | /* Function: m32r_write_sp | |
685 | Because SP is really a read-only register that mirrors either SPU or SPI, | |
686 | we must actually write one of those two as well, depending on PSW. */ | |
687 | ||
688 | void | |
fba45db2 | 689 | m32r_write_sp (CORE_ADDR val) |
c906108c SS |
690 | { |
691 | unsigned long psw = read_register (PSW_REGNUM); | |
692 | ||
c5aa993b | 693 | if (psw & 0x80) /* stack mode: user or interrupt */ |
c906108c SS |
694 | write_register (SPU_REGNUM, val); |
695 | else | |
696 | write_register (SPI_REGNUM, val); | |
697 | write_register (SP_REGNUM, val); | |
698 | } | |
699 | ||
700 | void | |
fba45db2 | 701 | _initialize_m32r_tdep (void) |
c906108c SS |
702 | { |
703 | tm_print_insn = print_insn_m32r; | |
704 | } |