fpu_calcea.c revision 1.18
1 /* $NetBSD: fpu_calcea.c,v 1.18 2007/03/09 16:33:27 tsutsui Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Gordon W. Ross 5 * portion Copyright (c) 1995 Ken Nakata 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 4. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by Gordon Ross 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: fpu_calcea.c,v 1.18 2007/03/09 16:33:27 tsutsui Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/signal.h> 39 #include <sys/systm.h> 40 #include <machine/frame.h> 41 #include <m68k/m68k.h> 42 43 #include "fpu_emulate.h" 44 45 /* 46 * Prototypes of static functions 47 */ 48 static int decode_ea6 __P((struct frame *frame, struct instruction *insn, 49 struct insn_ea *ea, int modreg)); 50 static int fetch_immed __P((struct frame *frame, struct instruction *insn, 51 int *dst)); 52 static int fetch_disp __P((struct frame *frame, struct instruction *insn, 53 int size, int *res)); 54 static int calc_ea __P((struct insn_ea *ea, char *ptr, char **eaddr)); 55 56 /* 57 * Helper routines for dealing with "effective address" values. 58 */ 59 60 /* 61 * Decode an effective address into internal form. 62 * Returns zero on success, else signal number. 63 */ 64 int 65 fpu_decode_ea(frame, insn, ea, modreg) 66 struct frame *frame; 67 struct instruction *insn; 68 struct insn_ea *ea; 69 int modreg; 70 { 71 int sig; 72 73 #ifdef DEBUG 74 if (insn->is_datasize < 0) { 75 panic("decode_ea: called with uninitialized datasize"); 76 } 77 #endif 78 79 sig = 0; 80 81 /* Set the most common value here. */ 82 ea->ea_regnum = 8 + (modreg & 7); 83 84 if ((modreg & 060) == 0) { 85 /* register direct */ 86 ea->ea_regnum = modreg & 0xf; 87 ea->ea_flags = EA_DIRECT; 88 #ifdef DEBUG_FPE 89 printf("decode_ea: register direct reg=%d\n", ea->ea_regnum); 90 #endif 91 } else if ((modreg & 077) == 074) { 92 /* immediate */ 93 ea->ea_flags = EA_IMMED; 94 sig = fetch_immed(frame, insn, &ea->ea_immed[0]); 95 #ifdef DEBUG_FPE 96 printf("decode_ea: immediate size=%d\n", insn->is_datasize); 97 #endif 98 } 99 /* 100 * rest of the address modes need to be separately 101 * handled for the LC040 and the others. 102 */ 103 #if 0 /* XXX */ 104 else if (frame->f_format == 4 && frame->f_fmt4.f_fa) { 105 /* LC040 */ 106 ea->ea_flags = EA_FRAME_EA; 107 ea->ea_fea = frame->f_fmt4.f_fa; 108 #ifdef DEBUG_FPE 109 printf("decode_ea: 68LC040 - in-frame EA (%p) size %d\n", 110 (void *)ea->ea_fea, insn->is_datasize); 111 #endif 112 if ((modreg & 070) == 030) { 113 /* postincrement mode */ 114 ea->ea_flags |= EA_POSTINCR; 115 } else if ((modreg & 070) == 040) { 116 /* predecrement mode */ 117 ea->ea_flags |= EA_PREDECR; 118 #ifdef M68060 119 #if defined(M68020) || defined(M68030) || defined(M68040) 120 if (cputype == CPU_68060) 121 #endif 122 if (insn->is_datasize == 12) 123 ea->ea_fea -= 8; 124 #endif 125 } 126 } 127 #endif /* XXX */ 128 else { 129 /* 020/030 */ 130 switch (modreg & 070) { 131 132 case 020: /* (An) */ 133 ea->ea_flags = 0; 134 #ifdef DEBUG_FPE 135 printf("decode_ea: register indirect reg=%d\n", ea->ea_regnum); 136 #endif 137 break; 138 139 case 030: /* (An)+ */ 140 ea->ea_flags = EA_POSTINCR; 141 #ifdef DEBUG_FPE 142 printf("decode_ea: reg indirect postincrement reg=%d\n", 143 ea->ea_regnum); 144 #endif 145 break; 146 147 case 040: /* -(An) */ 148 ea->ea_flags = EA_PREDECR; 149 #ifdef DEBUG_FPE 150 printf("decode_ea: reg indirect predecrement reg=%d\n", 151 ea->ea_regnum); 152 #endif 153 break; 154 155 case 050: /* (d16,An) */ 156 ea->ea_flags = EA_OFFSET; 157 sig = fetch_disp(frame, insn, 1, &ea->ea_offset); 158 #ifdef DEBUG_FPE 159 printf("decode_ea: reg indirect with displacement reg=%d\n", 160 ea->ea_regnum); 161 #endif 162 break; 163 164 case 060: /* (d8,An,Xn) */ 165 ea->ea_flags = EA_INDEXED; 166 sig = decode_ea6(frame, insn, ea, modreg); 167 break; 168 169 case 070: /* misc. */ 170 ea->ea_regnum = (modreg & 7); 171 switch (modreg & 7) { 172 173 case 0: /* (xxxx).W */ 174 ea->ea_flags = EA_ABS; 175 sig = fetch_disp(frame, insn, 1, &ea->ea_absaddr); 176 #ifdef DEBUG_FPE 177 printf("decode_ea: absolute address (word)\n"); 178 #endif 179 break; 180 181 case 1: /* (xxxxxxxx).L */ 182 ea->ea_flags = EA_ABS; 183 sig = fetch_disp(frame, insn, 2, &ea->ea_absaddr); 184 #ifdef DEBUG_FPE 185 printf("decode_ea: absolute address (long)\n"); 186 #endif 187 break; 188 189 case 2: /* (d16,PC) */ 190 ea->ea_flags = EA_PC_REL | EA_OFFSET; 191 sig = fetch_disp(frame, insn, 1, &ea->ea_absaddr); 192 #ifdef DEBUG_FPE 193 printf("decode_ea: pc relative word displacement\n"); 194 #endif 195 break; 196 197 case 3: /* (d8,PC,Xn) */ 198 ea->ea_flags = EA_PC_REL | EA_INDEXED; 199 sig = decode_ea6(frame, insn, ea, modreg); 200 break; 201 202 case 4: /* #data */ 203 /* it should have been taken care of earlier */ 204 default: 205 #ifdef DEBUG_FPE 206 printf("decode_ea: invalid addr mode (7,%d)\n", modreg & 7); 207 #endif 208 return SIGILL; 209 } /* switch for mode 7 */ 210 break; 211 } /* switch mode */ 212 } 213 ea->ea_moffs = 0; 214 215 return sig; 216 } 217 218 /* 219 * Decode Mode=6 address modes 220 */ 221 static int 222 decode_ea6(frame, insn, ea, modreg) 223 struct frame *frame; 224 struct instruction *insn; 225 struct insn_ea *ea; 226 int modreg; 227 { 228 int extword, idx; 229 int basedisp, outerdisp; 230 int bd_size, od_size; 231 int sig; 232 233 extword = fusword((void *) (insn->is_pc + insn->is_advance)); 234 if (extword < 0) { 235 return SIGSEGV; 236 } 237 insn->is_advance += 2; 238 239 /* get register index */ 240 ea->ea_idxreg = (extword >> 12) & 0xf; 241 idx = frame->f_regs[ea->ea_idxreg]; 242 if ((extword & 0x0800) == 0) { 243 /* if word sized index, sign-extend */ 244 idx &= 0xffff; 245 if (idx & 0x8000) { 246 idx |= 0xffff0000; 247 } 248 } 249 /* scale register index */ 250 idx <<= ((extword >>9) & 3); 251 252 if ((extword & 0x100) == 0) { 253 /* brief extension word - sign-extend the displacement */ 254 basedisp = (extword & 0xff); 255 if (basedisp & 0x80) { 256 basedisp |= 0xffffff00; 257 } 258 259 ea->ea_basedisp = idx + basedisp; 260 ea->ea_outerdisp = 0; 261 #if DEBUG_FPE 262 printf("decode_ea6: brief ext word idxreg=%d, basedisp=%08x\n", 263 ea->ea_idxreg, ea->ea_basedisp); 264 #endif 265 } else { 266 /* full extension word */ 267 if (extword & 0x80) { 268 ea->ea_flags |= EA_BASE_SUPPRSS; 269 } 270 bd_size = ((extword >> 4) & 3) - 1; 271 od_size = (extword & 3) - 1; 272 sig = fetch_disp(frame, insn, bd_size, &basedisp); 273 if (sig) { 274 return sig; 275 } 276 if (od_size >= 0) { 277 ea->ea_flags |= EA_MEM_INDIR; 278 } 279 sig = fetch_disp(frame, insn, od_size, &outerdisp); 280 if (sig) { 281 return sig; 282 } 283 284 switch (extword & 0x44) { 285 case 0: /* preindexed */ 286 ea->ea_basedisp = basedisp + idx; 287 ea->ea_outerdisp = outerdisp; 288 break; 289 case 4: /* postindexed */ 290 ea->ea_basedisp = basedisp; 291 ea->ea_outerdisp = outerdisp + idx; 292 break; 293 case 0x40: /* no index */ 294 ea->ea_basedisp = basedisp; 295 ea->ea_outerdisp = outerdisp; 296 break; 297 default: 298 #ifdef DEBUG 299 printf("decode_ea6: invalid indirect mode: ext word %04x\n", 300 extword); 301 #endif 302 return SIGILL; 303 break; 304 } 305 #if DEBUG_FPE 306 printf("decode_ea6: full ext idxreg=%d, basedisp=%x, outerdisp=%x\n", 307 ea->ea_idxreg, ea->ea_basedisp, ea->ea_outerdisp); 308 #endif 309 } 310 #if DEBUG_FPE 311 printf("decode_ea6: regnum=%d, flags=%x\n", 312 ea->ea_regnum, ea->ea_flags); 313 #endif 314 return 0; 315 } 316 317 /* 318 * Load a value from an effective address. 319 * Returns zero on success, else signal number. 320 */ 321 int 322 fpu_load_ea(frame, insn, ea, dst) 323 struct frame *frame; 324 struct instruction *insn; 325 struct insn_ea *ea; 326 char *dst; 327 { 328 int *reg; 329 char *src; 330 int len, step; 331 int sig; 332 333 #ifdef DIAGNOSTIC 334 if (ea->ea_regnum & ~0xF) { 335 panic("load_ea: bad regnum"); 336 } 337 #endif 338 339 #ifdef DEBUG_FPE 340 printf("load_ea: frame at %p\n", frame); 341 #endif 342 /* dst is always int or larger. */ 343 len = insn->is_datasize; 344 if (len < 4) { 345 dst += (4 - len); 346 } 347 step = (len == 1 && ea->ea_regnum == 15 /* sp */) ? 2 : len; 348 349 #if 0 350 if (ea->ea_flags & EA_FRAME_EA) { 351 /* Using LC040 frame EA */ 352 #ifdef DEBUG_FPE 353 if (ea->ea_flags & (EA_PREDECR|EA_POSTINCR)) { 354 printf("load_ea: frame ea %08x w/r%d\n", 355 ea->ea_fea, ea->ea_regnum); 356 } else { 357 printf("load_ea: frame ea %08x\n", ea->ea_fea); 358 } 359 #endif 360 src = (char *)ea->ea_fea; 361 copyin(src + ea->ea_moffs, dst, len); 362 if (ea->ea_flags & EA_PREDECR) { 363 frame->f_regs[ea->ea_regnum] = ea->ea_fea; 364 ea->ea_fea -= step; 365 ea->ea_moffs = 0; 366 } else if (ea->ea_flags & EA_POSTINCR) { 367 ea->ea_fea += step; 368 frame->f_regs[ea->ea_regnum] = ea->ea_fea; 369 ea->ea_moffs = 0; 370 } else { 371 ea->ea_moffs += step; 372 } 373 /* That's it, folks */ 374 } else 375 #endif 376 if (ea->ea_flags & EA_DIRECT) { 377 if (len > 4) { 378 #ifdef DEBUG 379 printf("load_ea: operand doesn't fit CPU reg\n"); 380 #endif 381 return SIGILL; 382 } 383 if (ea->ea_moffs > 0) { 384 #ifdef DEBUG 385 printf("load_ea: more than one move from CPU reg\n"); 386 #endif 387 return SIGILL; 388 } 389 src = (char *)&frame->f_regs[ea->ea_regnum]; 390 /* The source is an int. */ 391 if (len < 4) { 392 src += (4 - len); 393 #ifdef DEBUG_FPE 394 printf("load_ea: short/byte opr - addr adjusted\n"); 395 #endif 396 } 397 #ifdef DEBUG_FPE 398 printf("load_ea: src %p\n", src); 399 #endif 400 memcpy(dst, src, len); 401 } else if (ea->ea_flags & EA_IMMED) { 402 #ifdef DEBUG_FPE 403 printf("load_ea: immed %08x%08x%08x size %d\n", 404 ea->ea_immed[0], ea->ea_immed[1], ea->ea_immed[2], len); 405 #endif 406 src = (char *)&ea->ea_immed[0]; 407 if (len < 4) { 408 src += (4 - len); 409 #ifdef DEBUG_FPE 410 printf("load_ea: short/byte immed opr - addr adjusted\n"); 411 #endif 412 } 413 memcpy(dst, src, len); 414 } else if (ea->ea_flags & EA_ABS) { 415 #ifdef DEBUG_FPE 416 printf("load_ea: abs addr %08x\n", ea->ea_absaddr); 417 #endif 418 src = (char *)ea->ea_absaddr; 419 copyin(src, dst, len); 420 } else /* register indirect */ { 421 if (ea->ea_flags & EA_PC_REL) { 422 #ifdef DEBUG_FPE 423 printf("load_ea: using PC\n"); 424 #endif 425 reg = NULL; 426 /* Grab the register contents. 4 is offset to the first 427 extension word from the opcode */ 428 src = (char *)insn->is_pc + 4; 429 #ifdef DEBUG_FPE 430 printf("load_ea: pc relative pc+4 = %p\n", src); 431 #endif 432 } else /* not PC relative */ { 433 #ifdef DEBUG_FPE 434 printf("load_ea: using register %c%d\n", 435 (ea->ea_regnum >= 8) ? 'a' : 'd', ea->ea_regnum & 7); 436 #endif 437 /* point to the register */ 438 reg = &frame->f_regs[ea->ea_regnum]; 439 440 if (ea->ea_flags & EA_PREDECR) { 441 #ifdef DEBUG_FPE 442 printf("load_ea: predecr mode - reg decremented\n"); 443 #endif 444 *reg -= step; 445 ea->ea_moffs = 0; 446 } 447 448 /* Grab the register contents. */ 449 src = (char *)*reg; 450 #ifdef DEBUG_FPE 451 printf("load_ea: reg indirect reg = %p\n", src); 452 #endif 453 } 454 455 sig = calc_ea(ea, src, &src); 456 if (sig) 457 return sig; 458 459 copyin(src + ea->ea_moffs, dst, len); 460 461 /* do post-increment */ 462 if (ea->ea_flags & EA_POSTINCR) { 463 if (ea->ea_flags & EA_PC_REL) { 464 #ifdef DEBUG 465 printf("load_ea: tried to postincrement PC\n"); 466 #endif 467 return SIGILL; 468 } 469 *reg += step; 470 ea->ea_moffs = 0; 471 #ifdef DEBUG_FPE 472 printf("load_ea: postinc mode - reg incremented\n"); 473 #endif 474 } else { 475 ea->ea_moffs += len; 476 } 477 } 478 479 return 0; 480 } 481 482 /* 483 * Store a value at the effective address. 484 * Returns zero on success, else signal number. 485 */ 486 int 487 fpu_store_ea(frame, insn, ea, src) 488 struct frame *frame; 489 struct instruction *insn; 490 struct insn_ea *ea; 491 char *src; 492 { 493 int *reg; 494 char *dst; 495 int len, step; 496 int sig; 497 498 #ifdef DIAGNOSTIC 499 if (ea->ea_regnum & ~0xf) { 500 panic("store_ea: bad regnum"); 501 } 502 #endif 503 504 if (ea->ea_flags & (EA_IMMED|EA_PC_REL)) { 505 /* not alterable address mode */ 506 #ifdef DEBUG 507 printf("store_ea: not alterable address mode\n"); 508 #endif 509 return SIGILL; 510 } 511 512 /* src is always int or larger. */ 513 len = insn->is_datasize; 514 if (len < 4) { 515 src += (4 - len); 516 } 517 step = (len == 1 && ea->ea_regnum == 15 /* sp */) ? 2 : len; 518 519 if (ea->ea_flags & EA_FRAME_EA) { 520 /* Using LC040 frame EA */ 521 #ifdef DEBUG_FPE 522 if (ea->ea_flags & (EA_PREDECR|EA_POSTINCR)) { 523 printf("store_ea: frame ea %08x w/r%d\n", 524 ea->ea_fea, ea->ea_regnum); 525 } else { 526 printf("store_ea: frame ea %08x\n", ea->ea_fea); 527 } 528 #endif 529 dst = (char *)ea->ea_fea; 530 copyout(src, dst + ea->ea_moffs, len); 531 if (ea->ea_flags & EA_PREDECR) { 532 frame->f_regs[ea->ea_regnum] = ea->ea_fea; 533 ea->ea_fea -= step; 534 ea->ea_moffs = 0; 535 } else if (ea->ea_flags & EA_POSTINCR) { 536 ea->ea_fea += step; 537 frame->f_regs[ea->ea_regnum] = ea->ea_fea; 538 ea->ea_moffs = 0; 539 } else { 540 ea->ea_moffs += step; 541 } 542 /* That's it, folks */ 543 } else if (ea->ea_flags & EA_ABS) { 544 #ifdef DEBUG_FPE 545 printf("store_ea: abs addr %08x\n", ea->ea_absaddr); 546 #endif 547 dst = (char *)ea->ea_absaddr; 548 copyout(src, dst + ea->ea_moffs, len); 549 ea->ea_moffs += len; 550 } else if (ea->ea_flags & EA_DIRECT) { 551 if (len > 4) { 552 #ifdef DEBUG 553 printf("store_ea: operand doesn't fit CPU reg\n"); 554 #endif 555 return SIGILL; 556 } 557 if (ea->ea_moffs > 0) { 558 #ifdef DEBUG 559 printf("store_ea: more than one move to CPU reg\n"); 560 #endif 561 return SIGILL; 562 } 563 dst = (char*)&frame->f_regs[ea->ea_regnum]; 564 /* The destination is an int. */ 565 if (len < 4) { 566 dst += (4 - len); 567 #ifdef DEBUG_FPE 568 printf("store_ea: short/byte opr - dst addr adjusted\n"); 569 #endif 570 } 571 #ifdef DEBUG_FPE 572 printf("store_ea: dst %p\n", dst); 573 #endif 574 memcpy(dst, src, len); 575 } else /* One of MANY indirect forms... */ { 576 #ifdef DEBUG_FPE 577 printf("store_ea: using register %c%d\n", 578 (ea->ea_regnum >= 8) ? 'a' : 'd', ea->ea_regnum & 7); 579 #endif 580 /* point to the register */ 581 reg = &(frame->f_regs[ea->ea_regnum]); 582 583 /* do pre-decrement */ 584 if (ea->ea_flags & EA_PREDECR) { 585 #ifdef DEBUG_FPE 586 printf("store_ea: predecr mode - reg decremented\n"); 587 #endif 588 *reg -= step; 589 ea->ea_moffs = 0; 590 } 591 592 /* calculate the effective address */ 593 sig = calc_ea(ea, (char *)*reg, &dst); 594 if (sig) 595 return sig; 596 597 #ifdef DEBUG_FPE 598 printf("store_ea: dst addr=%p+%d\n", dst, ea->ea_moffs); 599 #endif 600 copyout(src, dst + ea->ea_moffs, len); 601 602 /* do post-increment */ 603 if (ea->ea_flags & EA_POSTINCR) { 604 *reg += step; 605 ea->ea_moffs = 0; 606 #ifdef DEBUG_FPE 607 printf("store_ea: postinc mode - reg incremented\n"); 608 #endif 609 } else { 610 ea->ea_moffs += len; 611 } 612 } 613 614 return 0; 615 } 616 617 /* 618 * fetch_immed: fetch immediate operand 619 */ 620 static int 621 fetch_immed(frame, insn, dst) 622 struct frame *frame; 623 struct instruction *insn; 624 int *dst; 625 { 626 int data, ext_bytes; 627 628 ext_bytes = insn->is_datasize; 629 630 if (0 < ext_bytes) { 631 data = fusword((void *) (insn->is_pc + insn->is_advance)); 632 if (data < 0) { 633 return SIGSEGV; 634 } 635 if (ext_bytes == 1) { 636 /* sign-extend byte to long */ 637 data &= 0xff; 638 if (data & 0x80) { 639 data |= 0xffffff00; 640 } 641 } else if (ext_bytes == 2) { 642 /* sign-extend word to long */ 643 data &= 0xffff; 644 if (data & 0x8000) { 645 data |= 0xffff0000; 646 } 647 } 648 insn->is_advance += 2; 649 dst[0] = data; 650 } 651 if (2 < ext_bytes) { 652 data = fusword((void *) (insn->is_pc + insn->is_advance)); 653 if (data < 0) { 654 return SIGSEGV; 655 } 656 insn->is_advance += 2; 657 dst[0] <<= 16; 658 dst[0] |= data; 659 } 660 if (4 < ext_bytes) { 661 data = fusword((void *) (insn->is_pc + insn->is_advance)); 662 if (data < 0) { 663 return SIGSEGV; 664 } 665 dst[1] = data << 16; 666 data = fusword((void *) (insn->is_pc + insn->is_advance + 2)); 667 if (data < 0) { 668 return SIGSEGV; 669 } 670 insn->is_advance += 4; 671 dst[1] |= data; 672 } 673 if (8 < ext_bytes) { 674 data = fusword((void *) (insn->is_pc + insn->is_advance)); 675 if (data < 0) { 676 return SIGSEGV; 677 } 678 dst[2] = data << 16; 679 data = fusword((void *) (insn->is_pc + insn->is_advance + 2)); 680 if (data < 0) { 681 return SIGSEGV; 682 } 683 insn->is_advance += 4; 684 dst[2] |= data; 685 } 686 687 return 0; 688 } 689 690 /* 691 * fetch_disp: fetch displacement in full extension words 692 */ 693 static int 694 fetch_disp(frame, insn, size, res) 695 struct frame *frame; 696 struct instruction *insn; 697 int size, *res; 698 { 699 int disp, word; 700 701 if (size == 1) { 702 word = fusword((void *) (insn->is_pc + insn->is_advance)); 703 if (word < 0) { 704 return SIGSEGV; 705 } 706 disp = word & 0xffff; 707 if (disp & 0x8000) { 708 /* sign-extend */ 709 disp |= 0xffff0000; 710 } 711 insn->is_advance += 2; 712 } else if (size == 2) { 713 word = fusword((void *) (insn->is_pc + insn->is_advance)); 714 if (word < 0) { 715 return SIGSEGV; 716 } 717 disp = word << 16; 718 word = fusword((void *) (insn->is_pc + insn->is_advance + 2)); 719 if (word < 0) { 720 return SIGSEGV; 721 } 722 disp |= (word & 0xffff); 723 insn->is_advance += 4; 724 } else { 725 disp = 0; 726 } 727 *res = disp; 728 return 0; 729 } 730 731 /* 732 * Calculates an effective address for all address modes except for 733 * register direct, absolute, and immediate modes. However, it does 734 * not take care of predecrement/postincrement of register content. 735 * Returns a signal value (0 == no error). 736 */ 737 static int 738 calc_ea(ea, ptr, eaddr) 739 struct insn_ea *ea; 740 char *ptr; /* base address (usually a register content) */ 741 char **eaddr; /* pointer to result pointer */ 742 { 743 int data, word; 744 745 #if DEBUG_FPE 746 printf("calc_ea: reg indirect (reg) = %p\n", ptr); 747 #endif 748 749 if (ea->ea_flags & EA_OFFSET) { 750 /* apply the signed offset */ 751 #if DEBUG_FPE 752 printf("calc_ea: offset %d\n", ea->ea_offset); 753 #endif 754 ptr += ea->ea_offset; 755 } else if (ea->ea_flags & EA_INDEXED) { 756 #if DEBUG_FPE 757 printf("calc_ea: indexed mode\n"); 758 #endif 759 760 if (ea->ea_flags & EA_BASE_SUPPRSS) { 761 /* base register is suppressed */ 762 ptr = (char *)ea->ea_basedisp; 763 } else { 764 ptr += ea->ea_basedisp; 765 } 766 767 if (ea->ea_flags & EA_MEM_INDIR) { 768 #if DEBUG_FPE 769 printf("calc_ea: mem indir mode: basedisp=%08x, outerdisp=%08x\n", 770 ea->ea_basedisp, ea->ea_outerdisp); 771 printf("calc_ea: addr fetched from %p\n", ptr); 772 #endif 773 /* memory indirect modes */ 774 word = fusword(ptr); 775 if (word < 0) { 776 return SIGSEGV; 777 } 778 word <<= 16; 779 data = fusword(ptr + 2); 780 if (data < 0) { 781 return SIGSEGV; 782 } 783 word |= data; 784 #if DEBUG_FPE 785 printf("calc_ea: fetched ptr 0x%08x\n", word); 786 #endif 787 ptr = (char *)word + ea->ea_outerdisp; 788 } 789 } 790 791 *eaddr = ptr; 792 793 return 0; 794 } 795
Indexes created Tue Sep 30 17:09:57 GMT 2025