| 1 | /* Target-dependent code for the Fujitsu FR30. |
| 2 | Copyright 1999, 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 | |
| 32 | /* An expression that tells us whether the function invocation represented |
| 33 | by FI does not have a frame on the stack associated with it. */ |
| 34 | int |
| 35 | fr30_frameless_function_invocation (fi) |
| 36 | struct frame_info *fi; |
| 37 | { |
| 38 | int frameless; |
| 39 | CORE_ADDR func_start, after_prologue; |
| 40 | func_start = (get_pc_function_start ((fi)->pc) + |
| 41 | FUNCTION_START_OFFSET); |
| 42 | after_prologue = func_start; |
| 43 | after_prologue = SKIP_PROLOGUE (after_prologue); |
| 44 | frameless = (after_prologue == func_start); |
| 45 | return frameless; |
| 46 | } |
| 47 | |
| 48 | /* Function: pop_frame |
| 49 | This routine gets called when either the user uses the `return' |
| 50 | command, or the call dummy breakpoint gets hit. */ |
| 51 | |
| 52 | void |
| 53 | fr30_pop_frame () |
| 54 | { |
| 55 | struct frame_info *frame = get_current_frame (); |
| 56 | int regnum; |
| 57 | CORE_ADDR sp = read_register (SP_REGNUM); |
| 58 | |
| 59 | if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)) |
| 60 | generic_pop_dummy_frame (); |
| 61 | else |
| 62 | { |
| 63 | write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); |
| 64 | |
| 65 | for (regnum = 0; regnum < NUM_REGS; regnum++) |
| 66 | if (frame->fsr.regs[regnum] != 0) |
| 67 | { |
| 68 | write_register (regnum, |
| 69 | read_memory_unsigned_integer (frame->fsr.regs[regnum], |
| 70 | REGISTER_RAW_SIZE (regnum))); |
| 71 | } |
| 72 | write_register (SP_REGNUM, sp + frame->framesize); |
| 73 | } |
| 74 | flush_cached_frames (); |
| 75 | } |
| 76 | |
| 77 | |
| 78 | /* Function: fr30_store_return_value |
| 79 | Put a value where a caller expects to see it. Used by the 'return' |
| 80 | command. */ |
| 81 | void |
| 82 | fr30_store_return_value (struct type *type, |
| 83 | char *valbuf) |
| 84 | { |
| 85 | /* Here's how the FR30 returns values (gleaned from gcc/config/ |
| 86 | fr30/fr30.h): |
| 87 | |
| 88 | If the return value is 32 bits long or less, it goes in r4. |
| 89 | |
| 90 | If the return value is 64 bits long or less, it goes in r4 (most |
| 91 | significant word) and r5 (least significant word. |
| 92 | |
| 93 | If the function returns a structure, of any size, the caller |
| 94 | passes the function an invisible first argument where the callee |
| 95 | should store the value. But GDB doesn't let you do that anyway. |
| 96 | |
| 97 | If you're returning a value smaller than a word, it's not really |
| 98 | necessary to zero the upper bytes of the register; the caller is |
| 99 | supposed to ignore them. However, the FR30 typically keeps its |
| 100 | values extended to the full register width, so we should emulate |
| 101 | that. */ |
| 102 | |
| 103 | /* The FR30 is big-endian, so if we return a small value (like a |
| 104 | short or a char), we need to position it correctly within the |
| 105 | register. We round the size up to a register boundary, and then |
| 106 | adjust the offset so as to place the value at the right end. */ |
| 107 | int value_size = TYPE_LENGTH (type); |
| 108 | int returned_size = (value_size + FR30_REGSIZE - 1) & ~(FR30_REGSIZE - 1); |
| 109 | int offset = (REGISTER_BYTE (RETVAL_REG) |
| 110 | + (returned_size - value_size)); |
| 111 | char *zeros = alloca (returned_size); |
| 112 | memset (zeros, 0, returned_size); |
| 113 | |
| 114 | write_register_bytes (REGISTER_BYTE (RETVAL_REG), zeros, returned_size); |
| 115 | write_register_bytes (offset, valbuf, value_size); |
| 116 | } |
| 117 | |
| 118 | |
| 119 | /* Function: skip_prologue |
| 120 | Return the address of the first code past the prologue of the function. */ |
| 121 | |
| 122 | CORE_ADDR |
| 123 | fr30_skip_prologue (CORE_ADDR pc) |
| 124 | { |
| 125 | CORE_ADDR func_addr, func_end; |
| 126 | |
| 127 | /* See what the symbol table says */ |
| 128 | |
| 129 | if (find_pc_partial_function (pc, NULL, &func_addr, &func_end)) |
| 130 | { |
| 131 | struct symtab_and_line sal; |
| 132 | |
| 133 | sal = find_pc_line (func_addr, 0); |
| 134 | |
| 135 | if (sal.line != 0 && sal.end < func_end) |
| 136 | { |
| 137 | return sal.end; |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | /* Either we didn't find the start of this function (nothing we can do), |
| 142 | or there's no line info, or the line after the prologue is after |
| 143 | the end of the function (there probably isn't a prologue). */ |
| 144 | |
| 145 | return pc; |
| 146 | } |
| 147 | |
| 148 | |
| 149 | /* Function: push_arguments |
| 150 | Setup arguments and RP for a call to the target. First four args |
| 151 | go in FIRST_ARGREG -> LAST_ARGREG, subsequent args go on stack... |
| 152 | Structs are passed by reference. XXX not right now Z.R. |
| 153 | 64 bit quantities (doubles and long longs) may be split between |
| 154 | the regs and the stack. |
| 155 | When calling a function that returns a struct, a pointer to the struct |
| 156 | is passed in as a secret first argument (always in FIRST_ARGREG). |
| 157 | |
| 158 | Stack space for the args has NOT been allocated: that job is up to us. |
| 159 | */ |
| 160 | |
| 161 | CORE_ADDR |
| 162 | fr30_push_arguments (nargs, args, sp, struct_return, struct_addr) |
| 163 | int nargs; |
| 164 | value_ptr *args; |
| 165 | CORE_ADDR sp; |
| 166 | int struct_return; |
| 167 | CORE_ADDR struct_addr; |
| 168 | { |
| 169 | int argreg; |
| 170 | int argnum; |
| 171 | int stack_offset; |
| 172 | struct stack_arg |
| 173 | { |
| 174 | char *val; |
| 175 | int len; |
| 176 | int offset; |
| 177 | }; |
| 178 | struct stack_arg *stack_args = |
| 179 | (struct stack_arg *) alloca (nargs * sizeof (struct stack_arg)); |
| 180 | int nstack_args = 0; |
| 181 | |
| 182 | argreg = FIRST_ARGREG; |
| 183 | |
| 184 | /* the struct_return pointer occupies the first parameter-passing reg */ |
| 185 | if (struct_return) |
| 186 | write_register (argreg++, struct_addr); |
| 187 | |
| 188 | stack_offset = 0; |
| 189 | |
| 190 | /* Process args from left to right. Store as many as allowed in |
| 191 | registers, save the rest to be pushed on the stack */ |
| 192 | for (argnum = 0; argnum < nargs; argnum++) |
| 193 | { |
| 194 | char *val; |
| 195 | value_ptr arg = args[argnum]; |
| 196 | struct type *arg_type = check_typedef (VALUE_TYPE (arg)); |
| 197 | struct type *target_type = TYPE_TARGET_TYPE (arg_type); |
| 198 | int len = TYPE_LENGTH (arg_type); |
| 199 | enum type_code typecode = TYPE_CODE (arg_type); |
| 200 | CORE_ADDR regval; |
| 201 | int newarg; |
| 202 | |
| 203 | val = (char *) VALUE_CONTENTS (arg); |
| 204 | |
| 205 | { |
| 206 | /* Copy the argument to general registers or the stack in |
| 207 | register-sized pieces. Large arguments are split between |
| 208 | registers and stack. */ |
| 209 | while (len > 0) |
| 210 | { |
| 211 | if (argreg <= LAST_ARGREG) |
| 212 | { |
| 213 | int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE; |
| 214 | regval = extract_address (val, partial_len); |
| 215 | |
| 216 | /* It's a simple argument being passed in a general |
| 217 | register. */ |
| 218 | write_register (argreg, regval); |
| 219 | argreg++; |
| 220 | len -= partial_len; |
| 221 | val += partial_len; |
| 222 | } |
| 223 | else |
| 224 | { |
| 225 | /* keep for later pushing */ |
| 226 | stack_args[nstack_args].val = val; |
| 227 | stack_args[nstack_args++].len = len; |
| 228 | break; |
| 229 | } |
| 230 | } |
| 231 | } |
| 232 | } |
| 233 | /* now do the real stack pushing, process args right to left */ |
| 234 | while (nstack_args--) |
| 235 | { |
| 236 | sp -= stack_args[nstack_args].len; |
| 237 | write_memory (sp, stack_args[nstack_args].val, |
| 238 | stack_args[nstack_args].len); |
| 239 | } |
| 240 | |
| 241 | /* Return adjusted stack pointer. */ |
| 242 | return sp; |
| 243 | } |
| 244 | |
| 245 | void _initialize_fr30_tdep PARAMS ((void)); |
| 246 | |
| 247 | void |
| 248 | _initialize_fr30_tdep () |
| 249 | { |
| 250 | extern int print_insn_fr30 (bfd_vma, disassemble_info *); |
| 251 | tm_print_insn = print_insn_fr30; |
| 252 | } |
| 253 | |
| 254 | /* Function: check_prologue_cache |
| 255 | Check if prologue for this frame's PC has already been scanned. |
| 256 | If it has, copy the relevant information about that prologue and |
| 257 | return non-zero. Otherwise do not copy anything and return zero. |
| 258 | |
| 259 | The information saved in the cache includes: |
| 260 | * the frame register number; |
| 261 | * the size of the stack frame; |
| 262 | * the offsets of saved regs (relative to the old SP); and |
| 263 | * the offset from the stack pointer to the frame pointer |
| 264 | |
| 265 | The cache contains only one entry, since this is adequate |
| 266 | for the typical sequence of prologue scan requests we get. |
| 267 | When performing a backtrace, GDB will usually ask to scan |
| 268 | the same function twice in a row (once to get the frame chain, |
| 269 | and once to fill in the extra frame information). |
| 270 | */ |
| 271 | |
| 272 | static struct frame_info prologue_cache; |
| 273 | |
| 274 | static int |
| 275 | check_prologue_cache (fi) |
| 276 | struct frame_info *fi; |
| 277 | { |
| 278 | int i; |
| 279 | |
| 280 | if (fi->pc == prologue_cache.pc) |
| 281 | { |
| 282 | fi->framereg = prologue_cache.framereg; |
| 283 | fi->framesize = prologue_cache.framesize; |
| 284 | fi->frameoffset = prologue_cache.frameoffset; |
| 285 | for (i = 0; i <= NUM_REGS; i++) |
| 286 | fi->fsr.regs[i] = prologue_cache.fsr.regs[i]; |
| 287 | return 1; |
| 288 | } |
| 289 | else |
| 290 | return 0; |
| 291 | } |
| 292 | |
| 293 | |
| 294 | /* Function: save_prologue_cache |
| 295 | Copy the prologue information from fi to the prologue cache. |
| 296 | */ |
| 297 | |
| 298 | static void |
| 299 | save_prologue_cache (fi) |
| 300 | struct frame_info *fi; |
| 301 | { |
| 302 | int i; |
| 303 | |
| 304 | prologue_cache.pc = fi->pc; |
| 305 | prologue_cache.framereg = fi->framereg; |
| 306 | prologue_cache.framesize = fi->framesize; |
| 307 | prologue_cache.frameoffset = fi->frameoffset; |
| 308 | |
| 309 | for (i = 0; i <= NUM_REGS; i++) |
| 310 | { |
| 311 | prologue_cache.fsr.regs[i] = fi->fsr.regs[i]; |
| 312 | } |
| 313 | } |
| 314 | |
| 315 | |
| 316 | /* Function: scan_prologue |
| 317 | Scan the prologue of the function that contains PC, and record what |
| 318 | we find in PI. PI->fsr must be zeroed by the called. Returns the |
| 319 | pc after the prologue. Note that the addresses saved in pi->fsr |
| 320 | are actually just frame relative (negative offsets from the frame |
| 321 | pointer). This is because we don't know the actual value of the |
| 322 | frame pointer yet. In some circumstances, the frame pointer can't |
| 323 | be determined till after we have scanned the prologue. */ |
| 324 | |
| 325 | static void |
| 326 | fr30_scan_prologue (fi) |
| 327 | struct frame_info *fi; |
| 328 | { |
| 329 | int sp_offset, fp_offset; |
| 330 | CORE_ADDR prologue_start, prologue_end, current_pc; |
| 331 | |
| 332 | /* Check if this function is already in the cache of frame information. */ |
| 333 | if (check_prologue_cache (fi)) |
| 334 | return; |
| 335 | |
| 336 | /* Assume there is no frame until proven otherwise. */ |
| 337 | fi->framereg = SP_REGNUM; |
| 338 | fi->framesize = 0; |
| 339 | fi->frameoffset = 0; |
| 340 | |
| 341 | /* Find the function prologue. If we can't find the function in |
| 342 | the symbol table, peek in the stack frame to find the PC. */ |
| 343 | if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end)) |
| 344 | { |
| 345 | /* Assume the prologue is everything between the first instruction |
| 346 | in the function and the first source line. */ |
| 347 | struct symtab_and_line sal = find_pc_line (prologue_start, 0); |
| 348 | |
| 349 | if (sal.line == 0) /* no line info, use current PC */ |
| 350 | prologue_end = fi->pc; |
| 351 | else if (sal.end < prologue_end) /* next line begins after fn end */ |
| 352 | prologue_end = sal.end; /* (probably means no prologue) */ |
| 353 | } |
| 354 | else |
| 355 | { |
| 356 | /* XXX Z.R. What now??? The following is entirely bogus */ |
| 357 | prologue_start = (read_memory_integer (fi->frame, 4) & 0x03fffffc) - 12; |
| 358 | prologue_end = prologue_start + 40; |
| 359 | } |
| 360 | |
| 361 | /* Now search the prologue looking for instructions that set up the |
| 362 | frame pointer, adjust the stack pointer, and save registers. */ |
| 363 | |
| 364 | sp_offset = fp_offset = 0; |
| 365 | for (current_pc = prologue_start; current_pc < prologue_end; current_pc += 2) |
| 366 | { |
| 367 | unsigned int insn; |
| 368 | |
| 369 | insn = read_memory_unsigned_integer (current_pc, 2); |
| 370 | |
| 371 | if ((insn & 0xfe00) == 0x8e00) /* stm0 or stm1 */ |
| 372 | { |
| 373 | int reg, mask = insn & 0xff; |
| 374 | |
| 375 | /* scan in one sweep - create virtual 16-bit mask from either insn's mask */ |
| 376 | if ((insn & 0x0100) == 0) |
| 377 | { |
| 378 | mask <<= 8; /* stm0 - move to upper byte in virtual mask */ |
| 379 | } |
| 380 | |
| 381 | /* Calculate offsets of saved registers (to be turned later into addresses). */ |
| 382 | for (reg = R4_REGNUM; reg <= R11_REGNUM; reg++) |
| 383 | if (mask & (1 << (15 - reg))) |
| 384 | { |
| 385 | sp_offset -= 4; |
| 386 | fi->fsr.regs[reg] = sp_offset; |
| 387 | } |
| 388 | } |
| 389 | else if ((insn & 0xfff0) == 0x1700) /* st rx,@-r15 */ |
| 390 | { |
| 391 | int reg = insn & 0xf; |
| 392 | |
| 393 | sp_offset -= 4; |
| 394 | fi->fsr.regs[reg] = sp_offset; |
| 395 | } |
| 396 | else if ((insn & 0xff00) == 0x0f00) /* enter */ |
| 397 | { |
| 398 | fp_offset = fi->fsr.regs[FP_REGNUM] = sp_offset - 4; |
| 399 | sp_offset -= 4 * (insn & 0xff); |
| 400 | fi->framereg = FP_REGNUM; |
| 401 | } |
| 402 | else if (insn == 0x1781) /* st rp,@-sp */ |
| 403 | { |
| 404 | sp_offset -= 4; |
| 405 | fi->fsr.regs[RP_REGNUM] = sp_offset; |
| 406 | } |
| 407 | else if (insn == 0x170e) /* st fp,@-sp */ |
| 408 | { |
| 409 | sp_offset -= 4; |
| 410 | fi->fsr.regs[FP_REGNUM] = sp_offset; |
| 411 | } |
| 412 | else if (insn == 0x8bfe) /* mov sp,fp */ |
| 413 | { |
| 414 | fi->framereg = FP_REGNUM; |
| 415 | } |
| 416 | else if ((insn & 0xff00) == 0xa300) /* addsp xx */ |
| 417 | { |
| 418 | sp_offset += 4 * (signed char) (insn & 0xff); |
| 419 | } |
| 420 | else if ((insn & 0xff0f) == 0x9b00 && /* ldi:20 xx,r0 */ |
| 421 | read_memory_unsigned_integer (current_pc + 4, 2) |
| 422 | == 0xac0f) /* sub r0,sp */ |
| 423 | { |
| 424 | /* large stack adjustment */ |
| 425 | sp_offset -= (((insn & 0xf0) << 12) | read_memory_unsigned_integer (current_pc + 2, 2)); |
| 426 | current_pc += 4; |
| 427 | } |
| 428 | else if (insn == 0x9f80 && /* ldi:32 xx,r0 */ |
| 429 | read_memory_unsigned_integer (current_pc + 6, 2) |
| 430 | == 0xac0f) /* sub r0,sp */ |
| 431 | { |
| 432 | /* large stack adjustment */ |
| 433 | sp_offset -= |
| 434 | (read_memory_unsigned_integer (current_pc + 2, 2) << 16 | |
| 435 | read_memory_unsigned_integer (current_pc + 4, 2)); |
| 436 | current_pc += 6; |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | /* The frame size is just the negative of the offset (from the original SP) |
| 441 | of the last thing thing we pushed on the stack. The frame offset is |
| 442 | [new FP] - [new SP]. */ |
| 443 | fi->framesize = -sp_offset; |
| 444 | fi->frameoffset = fp_offset - sp_offset; |
| 445 | |
| 446 | save_prologue_cache (fi); |
| 447 | } |
| 448 | |
| 449 | /* Function: init_extra_frame_info |
| 450 | Setup the frame's frame pointer, pc, and frame addresses for saved |
| 451 | registers. Most of the work is done in scan_prologue(). |
| 452 | |
| 453 | Note that when we are called for the last frame (currently active frame), |
| 454 | that fi->pc and fi->frame will already be setup. However, fi->frame will |
| 455 | be valid only if this routine uses FP. For previous frames, fi-frame will |
| 456 | always be correct (since that is derived from fr30_frame_chain ()). |
| 457 | |
| 458 | We can be called with the PC in the call dummy under two circumstances. |
| 459 | First, during normal backtracing, second, while figuring out the frame |
| 460 | pointer just prior to calling the target function (see run_stack_dummy). */ |
| 461 | |
| 462 | void |
| 463 | fr30_init_extra_frame_info (fi) |
| 464 | struct frame_info *fi; |
| 465 | { |
| 466 | int reg; |
| 467 | |
| 468 | if (fi->next) |
| 469 | fi->pc = FRAME_SAVED_PC (fi->next); |
| 470 | |
| 471 | memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs); |
| 472 | |
| 473 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 474 | { |
| 475 | /* We need to setup fi->frame here because run_stack_dummy gets it wrong |
| 476 | by assuming it's always FP. */ |
| 477 | fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM); |
| 478 | fi->framesize = 0; |
| 479 | fi->frameoffset = 0; |
| 480 | return; |
| 481 | } |
| 482 | fr30_scan_prologue (fi); |
| 483 | |
| 484 | if (!fi->next) /* this is the innermost frame? */ |
| 485 | fi->frame = read_register (fi->framereg); |
| 486 | else |
| 487 | /* not the innermost frame */ |
| 488 | /* If we have an FP, the callee saved it. */ if (fi->framereg == FP_REGNUM) |
| 489 | if (fi->next->fsr.regs[fi->framereg] != 0) |
| 490 | fi->frame = read_memory_integer (fi->next->fsr.regs[fi->framereg], |
| 491 | 4); |
| 492 | /* Calculate actual addresses of saved registers using offsets determined |
| 493 | by fr30_scan_prologue. */ |
| 494 | for (reg = 0; reg < NUM_REGS; reg++) |
| 495 | if (fi->fsr.regs[reg] != 0) |
| 496 | { |
| 497 | fi->fsr.regs[reg] += fi->frame + fi->framesize - fi->frameoffset; |
| 498 | } |
| 499 | } |
| 500 | |
| 501 | /* Function: find_callers_reg |
| 502 | Find REGNUM on the stack. Otherwise, it's in an active register. |
| 503 | One thing we might want to do here is to check REGNUM against the |
| 504 | clobber mask, and somehow flag it as invalid if it isn't saved on |
| 505 | the stack somewhere. This would provide a graceful failure mode |
| 506 | when trying to get the value of caller-saves registers for an inner |
| 507 | frame. */ |
| 508 | |
| 509 | CORE_ADDR |
| 510 | fr30_find_callers_reg (fi, regnum) |
| 511 | struct frame_info *fi; |
| 512 | int regnum; |
| 513 | { |
| 514 | for (; fi; fi = fi->next) |
| 515 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 516 | return generic_read_register_dummy (fi->pc, fi->frame, regnum); |
| 517 | else if (fi->fsr.regs[regnum] != 0) |
| 518 | return read_memory_unsigned_integer (fi->fsr.regs[regnum], |
| 519 | REGISTER_RAW_SIZE (regnum)); |
| 520 | |
| 521 | return read_register (regnum); |
| 522 | } |
| 523 | |
| 524 | |
| 525 | /* Function: frame_chain |
| 526 | Figure out the frame prior to FI. Unfortunately, this involves |
| 527 | scanning the prologue of the caller, which will also be done |
| 528 | shortly by fr30_init_extra_frame_info. For the dummy frame, we |
| 529 | just return the stack pointer that was in use at the time the |
| 530 | function call was made. */ |
| 531 | |
| 532 | |
| 533 | CORE_ADDR |
| 534 | fr30_frame_chain (fi) |
| 535 | struct frame_info *fi; |
| 536 | { |
| 537 | CORE_ADDR fn_start, callers_pc, fp; |
| 538 | struct frame_info caller_fi; |
| 539 | int framereg; |
| 540 | |
| 541 | /* is this a dummy frame? */ |
| 542 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 543 | return fi->frame; /* dummy frame same as caller's frame */ |
| 544 | |
| 545 | /* is caller-of-this a dummy frame? */ |
| 546 | callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */ |
| 547 | fp = fr30_find_callers_reg (fi, FP_REGNUM); |
| 548 | if (PC_IN_CALL_DUMMY (callers_pc, fp, fp)) |
| 549 | return fp; /* dummy frame's frame may bear no relation to ours */ |
| 550 | |
| 551 | if (find_pc_partial_function (fi->pc, 0, &fn_start, 0)) |
| 552 | if (fn_start == entry_point_address ()) |
| 553 | return 0; /* in _start fn, don't chain further */ |
| 554 | |
| 555 | framereg = fi->framereg; |
| 556 | |
| 557 | /* If the caller is the startup code, we're at the end of the chain. */ |
| 558 | if (find_pc_partial_function (callers_pc, 0, &fn_start, 0)) |
| 559 | if (fn_start == entry_point_address ()) |
| 560 | return 0; |
| 561 | |
| 562 | memset (&caller_fi, 0, sizeof (caller_fi)); |
| 563 | caller_fi.pc = callers_pc; |
| 564 | fr30_scan_prologue (&caller_fi); |
| 565 | framereg = caller_fi.framereg; |
| 566 | |
| 567 | /* If the caller used a frame register, return its value. |
| 568 | Otherwise, return the caller's stack pointer. */ |
| 569 | if (framereg == FP_REGNUM) |
| 570 | return fr30_find_callers_reg (fi, framereg); |
| 571 | else |
| 572 | return fi->frame + fi->framesize; |
| 573 | } |
| 574 | |
| 575 | /* Function: frame_saved_pc |
| 576 | Find the caller of this frame. We do this by seeing if RP_REGNUM |
| 577 | is saved in the stack anywhere, otherwise we get it from the |
| 578 | registers. If the inner frame is a dummy frame, return its PC |
| 579 | instead of RP, because that's where "caller" of the dummy-frame |
| 580 | will be found. */ |
| 581 | |
| 582 | CORE_ADDR |
| 583 | fr30_frame_saved_pc (fi) |
| 584 | struct frame_info *fi; |
| 585 | { |
| 586 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 587 | return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM); |
| 588 | else |
| 589 | return fr30_find_callers_reg (fi, RP_REGNUM); |
| 590 | } |
| 591 | |
| 592 | /* Function: fix_call_dummy |
| 593 | Pokes the callee function's address into the CALL_DUMMY assembly stub. |
| 594 | Assumes that the CALL_DUMMY looks like this: |
| 595 | jarl <offset24>, r31 |
| 596 | trap |
| 597 | */ |
| 598 | |
| 599 | int |
| 600 | fr30_fix_call_dummy (dummy, sp, fun, nargs, args, type, gcc_p) |
| 601 | char *dummy; |
| 602 | CORE_ADDR sp; |
| 603 | CORE_ADDR fun; |
| 604 | int nargs; |
| 605 | value_ptr *args; |
| 606 | struct type *type; |
| 607 | int gcc_p; |
| 608 | { |
| 609 | long offset24; |
| 610 | |
| 611 | offset24 = (long) fun - (long) entry_point_address (); |
| 612 | offset24 &= 0x3fffff; |
| 613 | offset24 |= 0xff800000; /* jarl <offset24>, r31 */ |
| 614 | |
| 615 | store_unsigned_integer ((unsigned int *) &dummy[2], 2, offset24 & 0xffff); |
| 616 | store_unsigned_integer ((unsigned int *) &dummy[0], 2, offset24 >> 16); |
| 617 | return 0; |
| 618 | } |