| 1 | /* Target-dependent code for the Mitsubishi m32r for GDB, the GNU debugger. |
| 2 | Copyright 1996, 1998, 1999, 2000, 2001 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, |
| 19 | Boston, MA 02111-1307, USA. */ |
| 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 | #include "regcache.h" |
| 32 | |
| 33 | /* Function: m32r_use_struct_convention |
| 34 | Return nonzero if call_function should allocate stack space for a |
| 35 | struct return? */ |
| 36 | int |
| 37 | m32r_use_struct_convention (int gcc_p, 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 (struct frame_info *fi, |
| 49 | struct frame_saved_regs *regaddr) |
| 50 | { |
| 51 | memcpy (regaddr, &fi->fsr, sizeof (struct frame_saved_regs)); |
| 52 | } |
| 53 | |
| 54 | /* Turn this on if you want to see just how much instruction decoding |
| 55 | if being done, its quite a lot |
| 56 | */ |
| 57 | #if 0 |
| 58 | static void |
| 59 | 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 |
| 110 | decode_prologue (CORE_ADDR start_pc, CORE_ADDR scan_limit, CORE_ADDR *pl_endptr, /* var parameter */ |
| 111 | unsigned long *framelength, struct frame_info *fi, |
| 112 | struct frame_saved_regs *fsr) |
| 113 | { |
| 114 | unsigned long framesize; |
| 115 | int insn; |
| 116 | int op1; |
| 117 | int maybe_one_more = 0; |
| 118 | CORE_ADDR after_prologue = 0; |
| 119 | CORE_ADDR after_stack_adjust = 0; |
| 120 | CORE_ADDR current_pc; |
| 121 | |
| 122 | |
| 123 | framesize = 0; |
| 124 | after_prologue = 0; |
| 125 | insn_debug (("rd prolog l(%d)\n", scan_limit - current_pc)); |
| 126 | |
| 127 | for (current_pc = start_pc; current_pc < scan_limit; current_pc += 2) |
| 128 | { |
| 129 | |
| 130 | insn = read_memory_unsigned_integer (current_pc, 2); |
| 131 | dump_insn ("insn-1", current_pc, insn); /* MTZ */ |
| 132 | |
| 133 | /* If this is a 32 bit instruction, we dont want to examine its |
| 134 | immediate data as though it were an instruction */ |
| 135 | if (current_pc & 0x02) |
| 136 | { /* Clear the parallel execution bit from 16 bit instruction */ |
| 137 | if (maybe_one_more) |
| 138 | { /* The last instruction was a branch, usually terminates |
| 139 | the series, but if this is a parallel instruction, |
| 140 | it may be a stack framing instruction */ |
| 141 | if (!(insn & 0x8000)) |
| 142 | { |
| 143 | insn_debug (("Really done")); |
| 144 | break; /* nope, we are really done */ |
| 145 | } |
| 146 | } |
| 147 | insn &= 0x7fff; /* decode this instruction further */ |
| 148 | } |
| 149 | else |
| 150 | { |
| 151 | if (maybe_one_more) |
| 152 | break; /* This isnt the one more */ |
| 153 | if (insn & 0x8000) |
| 154 | { |
| 155 | insn_debug (("32 bit insn\n")); |
| 156 | if (current_pc == scan_limit) |
| 157 | scan_limit += 2; /* extend the search */ |
| 158 | current_pc += 2; /* skip the immediate data */ |
| 159 | if (insn == 0x8faf) /* add3 sp, sp, xxxx */ |
| 160 | /* add 16 bit sign-extended offset */ |
| 161 | { |
| 162 | insn_debug (("stack increment\n")); |
| 163 | framesize += -((short) read_memory_unsigned_integer (current_pc, 2)); |
| 164 | } |
| 165 | else |
| 166 | { |
| 167 | if (((insn >> 8) == 0xe4) && /* ld24 r4, xxxxxx; sub sp, r4 */ |
| 168 | read_memory_unsigned_integer (current_pc + 2, 2) == 0x0f24) |
| 169 | { /* subtract 24 bit sign-extended negative-offset */ |
| 170 | dump_insn ("insn-2", current_pc + 2, insn); |
| 171 | insn = read_memory_unsigned_integer (current_pc - 2, 4); |
| 172 | dump_insn ("insn-3(l4)", current_pc - 2, insn); |
| 173 | if (insn & 0x00800000) /* sign extend */ |
| 174 | insn |= 0xff000000; /* negative */ |
| 175 | else |
| 176 | insn &= 0x00ffffff; /* positive */ |
| 177 | framesize += insn; |
| 178 | } |
| 179 | } |
| 180 | after_prologue = current_pc; |
| 181 | continue; |
| 182 | } |
| 183 | } |
| 184 | op1 = insn & 0xf000; /* isolate just the first nibble */ |
| 185 | |
| 186 | if ((insn & 0xf0ff) == 0x207f) |
| 187 | { /* st reg, @-sp */ |
| 188 | int regno; |
| 189 | insn_debug (("push\n")); |
| 190 | #if 0 /* No, PUSH FP is not an indication that we will use a frame pointer. */ |
| 191 | if (((insn & 0xffff) == 0x2d7f) && fi) |
| 192 | fi->using_frame_pointer = 1; |
| 193 | #endif |
| 194 | framesize += 4; |
| 195 | #if 0 |
| 196 | /* Why should we increase the scan limit, just because we did a push? |
| 197 | And if there is a reason, surely we would only want to do it if we |
| 198 | had already reached the scan limit... */ |
| 199 | if (current_pc == scan_limit) |
| 200 | scan_limit += 2; |
| 201 | #endif |
| 202 | regno = ((insn >> 8) & 0xf); |
| 203 | if (fsr) /* save_regs offset */ |
| 204 | fsr->regs[regno] = framesize; |
| 205 | after_prologue = 0; |
| 206 | continue; |
| 207 | } |
| 208 | if ((insn >> 8) == 0x4f) /* addi sp, xx */ |
| 209 | /* add 8 bit sign-extended offset */ |
| 210 | { |
| 211 | int stack_adjust = (char) (insn & 0xff); |
| 212 | |
| 213 | /* there are probably two of these stack adjustments: |
| 214 | 1) A negative one in the prologue, and |
| 215 | 2) A positive one in the epilogue. |
| 216 | We are only interested in the first one. */ |
| 217 | |
| 218 | if (stack_adjust < 0) |
| 219 | { |
| 220 | framesize -= stack_adjust; |
| 221 | after_prologue = 0; |
| 222 | /* A frameless function may have no "mv fp, sp". |
| 223 | In that case, this is the end of the prologue. */ |
| 224 | after_stack_adjust = current_pc + 2; |
| 225 | } |
| 226 | continue; |
| 227 | } |
| 228 | if (insn == 0x1d8f) |
| 229 | { /* mv fp, sp */ |
| 230 | if (fi) |
| 231 | fi->using_frame_pointer = 1; /* fp is now valid */ |
| 232 | insn_debug (("done fp found\n")); |
| 233 | after_prologue = current_pc + 2; |
| 234 | break; /* end of stack adjustments */ |
| 235 | } |
| 236 | if (insn == 0x7000) /* Nop looks like a branch, continue explicitly */ |
| 237 | { |
| 238 | insn_debug (("nop\n")); |
| 239 | after_prologue = current_pc + 2; |
| 240 | continue; /* nop occurs between pushes */ |
| 241 | } |
| 242 | /* End of prolog if any of these are branch instructions */ |
| 243 | if ((op1 == 0x7000) |
| 244 | || (op1 == 0xb000) |
| 245 | || (op1 == 0xf000)) |
| 246 | { |
| 247 | after_prologue = current_pc; |
| 248 | insn_debug (("Done: branch\n")); |
| 249 | maybe_one_more = 1; |
| 250 | continue; |
| 251 | } |
| 252 | /* Some of the branch instructions are mixed with other types */ |
| 253 | if (op1 == 0x1000) |
| 254 | { |
| 255 | int subop = insn & 0x0ff0; |
| 256 | if ((subop == 0x0ec0) || (subop == 0x0fc0)) |
| 257 | { |
| 258 | insn_debug (("done: jmp\n")); |
| 259 | after_prologue = current_pc; |
| 260 | maybe_one_more = 1; |
| 261 | continue; /* jmp , jl */ |
| 262 | } |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | if (current_pc >= scan_limit) |
| 267 | { |
| 268 | if (pl_endptr) |
| 269 | { |
| 270 | #if 1 |
| 271 | if (after_stack_adjust != 0) |
| 272 | /* We did not find a "mv fp,sp", but we DID find |
| 273 | a stack_adjust. Is it safe to use that as the |
| 274 | end of the prologue? I just don't know. */ |
| 275 | { |
| 276 | *pl_endptr = after_stack_adjust; |
| 277 | if (framelength) |
| 278 | *framelength = framesize; |
| 279 | } |
| 280 | else |
| 281 | #endif |
| 282 | /* We reached the end of the loop without finding the end |
| 283 | of the prologue. No way to win -- we should report failure. |
| 284 | The way we do that is to return the original start_pc. |
| 285 | GDB will set a breakpoint at the start of the function (etc.) */ |
| 286 | *pl_endptr = start_pc; |
| 287 | } |
| 288 | return; |
| 289 | } |
| 290 | if (after_prologue == 0) |
| 291 | after_prologue = current_pc; |
| 292 | |
| 293 | insn_debug ((" framesize %d, firstline %08x\n", framesize, after_prologue)); |
| 294 | if (framelength) |
| 295 | *framelength = framesize; |
| 296 | if (pl_endptr) |
| 297 | *pl_endptr = after_prologue; |
| 298 | } /* decode_prologue */ |
| 299 | |
| 300 | /* Function: skip_prologue |
| 301 | Find end of function prologue */ |
| 302 | |
| 303 | CORE_ADDR |
| 304 | m32r_skip_prologue (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 (struct frame_info *fi, struct frame_saved_regs *fsr) |
| 339 | { |
| 340 | struct symtab_and_line sal; |
| 341 | CORE_ADDR prologue_start, prologue_end, current_pc; |
| 342 | unsigned long framesize = 0; |
| 343 | |
| 344 | /* this code essentially duplicates skip_prologue, |
| 345 | but we need the start address below. */ |
| 346 | |
| 347 | if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end)) |
| 348 | { |
| 349 | sal = find_pc_line (prologue_start, 0); |
| 350 | |
| 351 | if (sal.line == 0) /* no line info, use current PC */ |
| 352 | if (prologue_start == entry_point_address ()) |
| 353 | return 0; |
| 354 | } |
| 355 | else |
| 356 | { |
| 357 | prologue_start = fi->pc; |
| 358 | prologue_end = prologue_start + 48; /* We're in the boondocks: |
| 359 | allow for 16 pushes, an add, |
| 360 | and "mv fp,sp" */ |
| 361 | } |
| 362 | #if 0 |
| 363 | prologue_end = min (prologue_end, fi->pc); |
| 364 | #endif |
| 365 | insn_debug (("fipc(%08x) start(%08x) end(%08x)\n", |
| 366 | fi->pc, prologue_start, prologue_end)); |
| 367 | prologue_end = min (prologue_end, prologue_start + DEFAULT_SEARCH_LIMIT); |
| 368 | decode_prologue (prologue_start, prologue_end, &prologue_end, &framesize, |
| 369 | fi, fsr); |
| 370 | return framesize; |
| 371 | } |
| 372 | |
| 373 | /* Function: init_extra_frame_info |
| 374 | This function actually figures out the frame address for a given pc and |
| 375 | sp. This is tricky on the m32r because we sometimes don't use an explicit |
| 376 | frame pointer, and the previous stack pointer isn't necessarily recorded |
| 377 | on the stack. The only reliable way to get this info is to |
| 378 | examine the prologue. */ |
| 379 | |
| 380 | void |
| 381 | m32r_init_extra_frame_info (struct frame_info *fi) |
| 382 | { |
| 383 | int reg; |
| 384 | |
| 385 | if (fi->next) |
| 386 | fi->pc = FRAME_SAVED_PC (fi->next); |
| 387 | |
| 388 | memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs); |
| 389 | |
| 390 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 391 | { |
| 392 | /* We need to setup fi->frame here because run_stack_dummy gets it wrong |
| 393 | by assuming it's always FP. */ |
| 394 | fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM); |
| 395 | fi->framesize = 0; |
| 396 | return; |
| 397 | } |
| 398 | else |
| 399 | { |
| 400 | fi->using_frame_pointer = 0; |
| 401 | fi->framesize = m32r_scan_prologue (fi, &fi->fsr); |
| 402 | |
| 403 | if (!fi->next) |
| 404 | if (fi->using_frame_pointer) |
| 405 | { |
| 406 | fi->frame = read_register (FP_REGNUM); |
| 407 | } |
| 408 | else |
| 409 | fi->frame = read_register (SP_REGNUM); |
| 410 | else |
| 411 | /* fi->next means this is not the innermost frame */ if (fi->using_frame_pointer) |
| 412 | /* we have an FP */ |
| 413 | if (fi->next->fsr.regs[FP_REGNUM] != 0) /* caller saved our FP */ |
| 414 | fi->frame = read_memory_integer (fi->next->fsr.regs[FP_REGNUM], 4); |
| 415 | for (reg = 0; reg < NUM_REGS; reg++) |
| 416 | if (fi->fsr.regs[reg] != 0) |
| 417 | fi->fsr.regs[reg] = fi->frame + fi->framesize - fi->fsr.regs[reg]; |
| 418 | } |
| 419 | } |
| 420 | |
| 421 | /* Function: m32r_virtual_frame_pointer |
| 422 | Return the register that the function uses for a frame pointer, |
| 423 | plus any necessary offset to be applied to the register before |
| 424 | any frame pointer offsets. */ |
| 425 | |
| 426 | void |
| 427 | m32r_virtual_frame_pointer (CORE_ADDR pc, long *reg, long *offset) |
| 428 | { |
| 429 | struct frame_info fi; |
| 430 | |
| 431 | /* Set up a dummy frame_info. */ |
| 432 | fi.next = NULL; |
| 433 | fi.prev = NULL; |
| 434 | fi.frame = 0; |
| 435 | fi.pc = pc; |
| 436 | |
| 437 | /* Analyze the prolog and fill in the extra info. */ |
| 438 | m32r_init_extra_frame_info (&fi); |
| 439 | |
| 440 | |
| 441 | /* Results will tell us which type of frame it uses. */ |
| 442 | if (fi.using_frame_pointer) |
| 443 | { |
| 444 | *reg = FP_REGNUM; |
| 445 | *offset = 0; |
| 446 | } |
| 447 | else |
| 448 | { |
| 449 | *reg = SP_REGNUM; |
| 450 | *offset = 0; |
| 451 | } |
| 452 | } |
| 453 | |
| 454 | /* Function: find_callers_reg |
| 455 | Find REGNUM on the stack. Otherwise, it's in an active register. One thing |
| 456 | we might want to do here is to check REGNUM against the clobber mask, and |
| 457 | somehow flag it as invalid if it isn't saved on the stack somewhere. This |
| 458 | would provide a graceful failure mode when trying to get the value of |
| 459 | caller-saves registers for an inner frame. */ |
| 460 | |
| 461 | CORE_ADDR |
| 462 | m32r_find_callers_reg (struct frame_info *fi, int regnum) |
| 463 | { |
| 464 | for (; fi; fi = fi->next) |
| 465 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 466 | return generic_read_register_dummy (fi->pc, fi->frame, regnum); |
| 467 | else if (fi->fsr.regs[regnum] != 0) |
| 468 | return read_memory_integer (fi->fsr.regs[regnum], |
| 469 | REGISTER_RAW_SIZE (regnum)); |
| 470 | return read_register (regnum); |
| 471 | } |
| 472 | |
| 473 | /* Function: frame_chain |
| 474 | Given a GDB frame, determine the address of the calling function's frame. |
| 475 | This will be used to create a new GDB frame struct, and then |
| 476 | INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame. |
| 477 | For m32r, we save the frame size when we initialize the frame_info. */ |
| 478 | |
| 479 | CORE_ADDR |
| 480 | m32r_frame_chain (struct frame_info *fi) |
| 481 | { |
| 482 | CORE_ADDR fn_start, callers_pc, fp; |
| 483 | |
| 484 | /* is this a dummy frame? */ |
| 485 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 486 | return fi->frame; /* dummy frame same as caller's frame */ |
| 487 | |
| 488 | /* is caller-of-this a dummy frame? */ |
| 489 | callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */ |
| 490 | fp = m32r_find_callers_reg (fi, FP_REGNUM); |
| 491 | if (PC_IN_CALL_DUMMY (callers_pc, fp, fp)) |
| 492 | return fp; /* dummy frame's frame may bear no relation to ours */ |
| 493 | |
| 494 | if (find_pc_partial_function (fi->pc, 0, &fn_start, 0)) |
| 495 | if (fn_start == entry_point_address ()) |
| 496 | return 0; /* in _start fn, don't chain further */ |
| 497 | if (fi->framesize == 0) |
| 498 | { |
| 499 | printf_filtered ("cannot determine frame size @ %s , pc(%s)\n", |
| 500 | paddr (fi->frame), |
| 501 | paddr (fi->pc)); |
| 502 | return 0; |
| 503 | } |
| 504 | insn_debug (("m32rx frame %08x\n", fi->frame + fi->framesize)); |
| 505 | return fi->frame + fi->framesize; |
| 506 | } |
| 507 | |
| 508 | /* Function: push_return_address (pc) |
| 509 | Set up the return address for the inferior function call. |
| 510 | Necessary for targets that don't actually execute a JSR/BSR instruction |
| 511 | (ie. when using an empty CALL_DUMMY) */ |
| 512 | |
| 513 | CORE_ADDR |
| 514 | m32r_push_return_address (CORE_ADDR pc, CORE_ADDR sp) |
| 515 | { |
| 516 | write_register (RP_REGNUM, CALL_DUMMY_ADDRESS ()); |
| 517 | return sp; |
| 518 | } |
| 519 | |
| 520 | |
| 521 | /* Function: pop_frame |
| 522 | Discard from the stack the innermost frame, |
| 523 | restoring all saved registers. */ |
| 524 | |
| 525 | struct frame_info * |
| 526 | m32r_pop_frame (struct frame_info *frame) |
| 527 | { |
| 528 | int regnum; |
| 529 | |
| 530 | if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)) |
| 531 | generic_pop_dummy_frame (); |
| 532 | else |
| 533 | { |
| 534 | for (regnum = 0; regnum < NUM_REGS; regnum++) |
| 535 | if (frame->fsr.regs[regnum] != 0) |
| 536 | write_register (regnum, |
| 537 | read_memory_integer (frame->fsr.regs[regnum], 4)); |
| 538 | |
| 539 | write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); |
| 540 | write_register (SP_REGNUM, read_register (FP_REGNUM)); |
| 541 | if (read_register (PSW_REGNUM) & 0x80) |
| 542 | write_register (SPU_REGNUM, read_register (SP_REGNUM)); |
| 543 | else |
| 544 | write_register (SPI_REGNUM, read_register (SP_REGNUM)); |
| 545 | } |
| 546 | flush_cached_frames (); |
| 547 | return NULL; |
| 548 | } |
| 549 | |
| 550 | /* Function: frame_saved_pc |
| 551 | Find the caller of this frame. We do this by seeing if RP_REGNUM is saved |
| 552 | in the stack anywhere, otherwise we get it from the registers. */ |
| 553 | |
| 554 | CORE_ADDR |
| 555 | m32r_frame_saved_pc (struct frame_info *fi) |
| 556 | { |
| 557 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 558 | return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM); |
| 559 | else |
| 560 | return m32r_find_callers_reg (fi, RP_REGNUM); |
| 561 | } |
| 562 | |
| 563 | /* Function: push_arguments |
| 564 | Setup the function arguments for calling a function in the inferior. |
| 565 | |
| 566 | On the Mitsubishi M32R architecture, there are four registers (R0 to R3) |
| 567 | which are dedicated for passing function arguments. Up to the first |
| 568 | four arguments (depending on size) may go into these registers. |
| 569 | The rest go on the stack. |
| 570 | |
| 571 | Arguments that are smaller than 4 bytes will still take up a whole |
| 572 | register or a whole 32-bit word on the stack, and will be |
| 573 | right-justified in the register or the stack word. This includes |
| 574 | chars, shorts, and small aggregate types. |
| 575 | |
| 576 | Arguments of 8 bytes size are split between two registers, if |
| 577 | available. If only one register is available, the argument will |
| 578 | be split between the register and the stack. Otherwise it is |
| 579 | passed entirely on the stack. Aggregate types with sizes between |
| 580 | 4 and 8 bytes are passed entirely on the stack, and are left-justified |
| 581 | within the double-word (as opposed to aggregates smaller than 4 bytes |
| 582 | which are right-justified). |
| 583 | |
| 584 | Aggregates of greater than 8 bytes are first copied onto the stack, |
| 585 | and then a pointer to the copy is passed in the place of the normal |
| 586 | argument (either in a register if available, or on the stack). |
| 587 | |
| 588 | Functions that must return an aggregate type can return it in the |
| 589 | normal return value registers (R0 and R1) if its size is 8 bytes or |
| 590 | less. For larger return values, the caller must allocate space for |
| 591 | the callee to copy the return value to. A pointer to this space is |
| 592 | passed as an implicit first argument, always in R0. */ |
| 593 | |
| 594 | CORE_ADDR |
| 595 | m32r_push_arguments (int nargs, value_ptr *args, CORE_ADDR sp, |
| 596 | unsigned char struct_return, CORE_ADDR struct_addr) |
| 597 | { |
| 598 | int stack_offset, stack_alloc; |
| 599 | int argreg; |
| 600 | int argnum; |
| 601 | struct type *type; |
| 602 | CORE_ADDR regval; |
| 603 | char *val; |
| 604 | char valbuf[4]; |
| 605 | int len; |
| 606 | int odd_sized_struct; |
| 607 | |
| 608 | /* first force sp to a 4-byte alignment */ |
| 609 | sp = sp & ~3; |
| 610 | |
| 611 | argreg = ARG0_REGNUM; |
| 612 | /* The "struct return pointer" pseudo-argument goes in R0 */ |
| 613 | if (struct_return) |
| 614 | write_register (argreg++, struct_addr); |
| 615 | |
| 616 | /* Now make sure there's space on the stack */ |
| 617 | for (argnum = 0, stack_alloc = 0; |
| 618 | argnum < nargs; argnum++) |
| 619 | stack_alloc += ((TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3); |
| 620 | sp -= stack_alloc; /* make room on stack for args */ |
| 621 | |
| 622 | |
| 623 | /* Now load as many as possible of the first arguments into |
| 624 | registers, and push the rest onto the stack. There are 16 bytes |
| 625 | in four registers available. Loop thru args from first to last. */ |
| 626 | |
| 627 | argreg = ARG0_REGNUM; |
| 628 | for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++) |
| 629 | { |
| 630 | type = VALUE_TYPE (args[argnum]); |
| 631 | len = TYPE_LENGTH (type); |
| 632 | memset (valbuf, 0, sizeof (valbuf)); |
| 633 | if (len < 4) |
| 634 | { /* value gets right-justified in the register or stack word */ |
| 635 | memcpy (valbuf + (4 - len), |
| 636 | (char *) VALUE_CONTENTS (args[argnum]), len); |
| 637 | val = valbuf; |
| 638 | } |
| 639 | else |
| 640 | val = (char *) VALUE_CONTENTS (args[argnum]); |
| 641 | |
| 642 | if (len > 4 && (len & 3) != 0) |
| 643 | odd_sized_struct = 1; /* such structs go entirely on stack */ |
| 644 | else |
| 645 | odd_sized_struct = 0; |
| 646 | while (len > 0) |
| 647 | { |
| 648 | if (argreg > ARGLAST_REGNUM || odd_sized_struct) |
| 649 | { /* must go on the stack */ |
| 650 | write_memory (sp + stack_offset, val, 4); |
| 651 | stack_offset += 4; |
| 652 | } |
| 653 | /* NOTE WELL!!!!! This is not an "else if" clause!!! |
| 654 | That's because some *&^%$ things get passed on the stack |
| 655 | AND in the registers! */ |
| 656 | if (argreg <= ARGLAST_REGNUM) |
| 657 | { /* there's room in a register */ |
| 658 | regval = extract_address (val, REGISTER_RAW_SIZE (argreg)); |
| 659 | write_register (argreg++, regval); |
| 660 | } |
| 661 | /* Store the value 4 bytes at a time. This means that things |
| 662 | larger than 4 bytes may go partly in registers and partly |
| 663 | on the stack. */ |
| 664 | len -= REGISTER_RAW_SIZE (argreg); |
| 665 | val += REGISTER_RAW_SIZE (argreg); |
| 666 | } |
| 667 | } |
| 668 | return sp; |
| 669 | } |
| 670 | |
| 671 | /* Function: fix_call_dummy |
| 672 | If there is real CALL_DUMMY code (eg. on the stack), this function |
| 673 | has the responsability to insert the address of the actual code that |
| 674 | is the target of the target function call. */ |
| 675 | |
| 676 | void |
| 677 | m32r_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs, |
| 678 | value_ptr *args, struct type *type, int gcc_p) |
| 679 | { |
| 680 | /* ld24 r8, <(imm24) fun> */ |
| 681 | *(unsigned long *) (dummy) = (fun & 0x00ffffff) | 0xe8000000; |
| 682 | } |
| 683 | |
| 684 | |
| 685 | /* Function: m32r_write_sp |
| 686 | Because SP is really a read-only register that mirrors either SPU or SPI, |
| 687 | we must actually write one of those two as well, depending on PSW. */ |
| 688 | |
| 689 | void |
| 690 | m32r_write_sp (CORE_ADDR val) |
| 691 | { |
| 692 | unsigned long psw = read_register (PSW_REGNUM); |
| 693 | |
| 694 | if (psw & 0x80) /* stack mode: user or interrupt */ |
| 695 | write_register (SPU_REGNUM, val); |
| 696 | else |
| 697 | write_register (SPI_REGNUM, val); |
| 698 | write_register (SP_REGNUM, val); |
| 699 | } |
| 700 | |
| 701 | void |
| 702 | _initialize_m32r_tdep (void) |
| 703 | { |
| 704 | tm_print_insn = print_insn_m32r; |
| 705 | } |