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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 | // SPDX-License-Identifier: GPL-2.0 /*---------------------------------------------------------------------------+ | fpu_entry.c | | | | The entry functions for wm-FPU-emu | | | | Copyright (C) 1992,1993,1994,1996,1997 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | | E-mail billm@suburbia.net | | | | See the files "README" and "COPYING" for further copyright and warranty | | information. | | | +---------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------+ | Note: | | The file contains code which accesses user memory. | | Emulator static data may change when user memory is accessed, due to | | other processes using the emulator while swapping is in progress. | +---------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------+ | math_emulate(), restore_i387_soft() and save_i387_soft() are the only | | entry points for wm-FPU-emu. | +---------------------------------------------------------------------------*/ #include <linux/signal.h> #include <linux/regset.h> #include <linux/uaccess.h> #include <asm/traps.h> #include <asm/user.h> #include <asm/fpu/api.h> #include "fpu_system.h" #include "fpu_emu.h" #include "exception.h" #include "control_w.h" #include "status_w.h" #define __BAD__ FPU_illegal /* Illegal on an 80486, causes SIGILL */ /* fcmovCC and f(u)comi(p) are enabled if CPUID(1).EDX(15) "cmov" is set */ /* WARNING: "u" entries are not documented by Intel in their 80486 manual and may not work on FPU clones or later Intel FPUs. Changes to support them provided by Linus Torvalds. */ static FUNC const st_instr_table[64] = { /* Opcode: d8 d9 da db */ /* dc dd de df */ /* c0..7 */ fadd__, fld_i_, fcmovb, fcmovnb, /* c0..7 */ fadd_i, ffree_, faddp_, ffreep,/*u*/ /* c8..f */ fmul__, fxch_i, fcmove, fcmovne, /* c8..f */ fmul_i, fxch_i,/*u*/ fmulp_, fxch_i,/*u*/ /* d0..7 */ fcom_st, fp_nop, fcmovbe, fcmovnbe, /* d0..7 */ fcom_st,/*u*/ fst_i_, fcompst,/*u*/ fstp_i,/*u*/ /* d8..f */ fcompst, fstp_i,/*u*/ fcmovu, fcmovnu, /* d8..f */ fcompst,/*u*/ fstp_i, fcompp, fstp_i,/*u*/ /* e0..7 */ fsub__, FPU_etc, __BAD__, finit_, /* e0..7 */ fsubri, fucom_, fsubrp, fstsw_, /* e8..f */ fsubr_, fconst, fucompp, fucomi_, /* e8..f */ fsub_i, fucomp, fsubp_, fucomip, /* f0..7 */ fdiv__, FPU_triga, __BAD__, fcomi_, /* f0..7 */ fdivri, __BAD__, fdivrp, fcomip, /* f8..f */ fdivr_, FPU_trigb, __BAD__, __BAD__, /* f8..f */ fdiv_i, __BAD__, fdivp_, __BAD__, }; #define _NONE_ 0 /* Take no special action */ #define _REG0_ 1 /* Need to check for not empty st(0) */ #define _REGI_ 2 /* Need to check for not empty st(0) and st(rm) */ #define _REGi_ 0 /* Uses st(rm) */ #define _PUSH_ 3 /* Need to check for space to push onto stack */ #define _null_ 4 /* Function illegal or not implemented */ #define _REGIi 5 /* Uses st(0) and st(rm), result to st(rm) */ #define _REGIp 6 /* Uses st(0) and st(rm), result to st(rm) then pop */ #define _REGIc 0 /* Compare st(0) and st(rm) */ #define _REGIn 0 /* Uses st(0) and st(rm), but handle checks later */ static u_char const type_table[64] = { /* Opcode: d8 d9 da db dc dd de df */ /* c0..7 */ _REGI_, _NONE_, _REGIn, _REGIn, _REGIi, _REGi_, _REGIp, _REGi_, /* c8..f */ _REGI_, _REGIn, _REGIn, _REGIn, _REGIi, _REGI_, _REGIp, _REGI_, /* d0..7 */ _REGIc, _NONE_, _REGIn, _REGIn, _REGIc, _REG0_, _REGIc, _REG0_, /* d8..f */ _REGIc, _REG0_, _REGIn, _REGIn, _REGIc, _REG0_, _REGIc, _REG0_, /* e0..7 */ _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_, /* e8..f */ _REGI_, _NONE_, _REGIc, _REGIc, _REGIi, _REGIc, _REGIp, _REGIc, /* f0..7 */ _REGI_, _NONE_, _null_, _REGIc, _REGIi, _null_, _REGIp, _REGIc, /* f8..f */ _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_, }; #ifdef RE_ENTRANT_CHECKING u_char emulating = 0; #endif /* RE_ENTRANT_CHECKING */ static int valid_prefix(u_char *Byte, u_char __user ** fpu_eip, overrides * override); void math_emulate(struct math_emu_info *info) { u_char FPU_modrm, byte1; unsigned short code; fpu_addr_modes addr_modes; int unmasked; FPU_REG loaded_data; FPU_REG *st0_ptr; u_char loaded_tag, st0_tag; void __user *data_address; struct address data_sel_off; struct address entry_sel_off; unsigned long code_base = 0; unsigned long code_limit = 0; /* Initialized to stop compiler warnings */ struct desc_struct code_descriptor; #ifdef RE_ENTRANT_CHECKING if (emulating) { printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n"); } RE_ENTRANT_CHECK_ON; #endif /* RE_ENTRANT_CHECKING */ FPU_info = info; FPU_ORIG_EIP = FPU_EIP; if ((FPU_EFLAGS & 0x00020000) != 0) { /* Virtual 8086 mode */ addr_modes.default_mode = VM86; FPU_EIP += code_base = FPU_CS << 4; code_limit = code_base + 0xffff; /* Assumes code_base <= 0xffff0000 */ } else if (FPU_CS == __USER_CS && FPU_DS == __USER_DS) { addr_modes.default_mode = 0; } else if (FPU_CS == __KERNEL_CS) { printk("math_emulate: %04x:%08lx\n", FPU_CS, FPU_EIP); panic("Math emulation needed in kernel"); } else { if ((FPU_CS & 4) != 4) { /* Must be in the LDT */ /* Can only handle segmented addressing via the LDT for now, and it must be 16 bit */ printk("FPU emulator: Unsupported addressing mode\n"); math_abort(FPU_info, SIGILL); } code_descriptor = FPU_get_ldt_descriptor(FPU_CS); if (code_descriptor.d) { /* The above test may be wrong, the book is not clear */ /* Segmented 32 bit protected mode */ addr_modes.default_mode = SEG32; } else { /* 16 bit protected mode */ addr_modes.default_mode = PM16; } FPU_EIP += code_base = seg_get_base(&code_descriptor); code_limit = seg_get_limit(&code_descriptor) + 1; code_limit *= seg_get_granularity(&code_descriptor); code_limit += code_base - 1; if (code_limit < code_base) code_limit = 0xffffffff; } FPU_lookahead = !(FPU_EFLAGS & X86_EFLAGS_TF); if (!valid_prefix(&byte1, (u_char __user **) & FPU_EIP, &addr_modes.override)) { RE_ENTRANT_CHECK_OFF; printk ("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n" "FPU emulator: self-modifying code! (emulation impossible)\n", byte1); RE_ENTRANT_CHECK_ON; EXCEPTION(EX_INTERNAL | 0x126); math_abort(FPU_info, SIGILL); } do_another_FPU_instruction: no_ip_update = 0; FPU_EIP++; /* We have fetched the prefix and first code bytes. */ if (addr_modes.default_mode) { /* This checks for the minimum instruction bytes. We also need to check any extra (address mode) code access. */ if (FPU_EIP > code_limit) math_abort(FPU_info, SIGSEGV); } if ((byte1 & 0xf8) != 0xd8) { if (byte1 == FWAIT_OPCODE) { if (partial_status & SW_Summary) goto do_the_FPU_interrupt; else goto FPU_fwait_done; } #ifdef PARANOID EXCEPTION(EX_INTERNAL | 0x128); math_abort(FPU_info, SIGILL); #endif /* PARANOID */ } RE_ENTRANT_CHECK_OFF; FPU_code_access_ok(1); FPU_get_user(FPU_modrm, (u_char __user *) FPU_EIP); RE_ENTRANT_CHECK_ON; FPU_EIP++; if (partial_status & SW_Summary) { /* Ignore the error for now if the current instruction is a no-wait control instruction */ /* The 80486 manual contradicts itself on this topic, but a real 80486 uses the following instructions: fninit, fnstenv, fnsave, fnstsw, fnstenv, fnclex. */ code = (FPU_modrm << 8) | byte1; if (!((((code & 0xf803) == 0xe003) || /* fnclex, fninit, fnstsw */ (((code & 0x3003) == 0x3001) && /* fnsave, fnstcw, fnstenv, fnstsw */ ((code & 0xc000) != 0xc000))))) { /* * We need to simulate the action of the kernel to FPU * interrupts here. */ do_the_FPU_interrupt: FPU_EIP = FPU_ORIG_EIP; /* Point to current FPU instruction. */ RE_ENTRANT_CHECK_OFF; current->thread.trap_nr = X86_TRAP_MF; current->thread.error_code = 0; send_sig(SIGFPE, current, 1); return; } } entry_sel_off.offset = FPU_ORIG_EIP; entry_sel_off.selector = FPU_CS; entry_sel_off.opcode = (byte1 << 8) | FPU_modrm; entry_sel_off.empty = 0; FPU_rm = FPU_modrm & 7; if (FPU_modrm < 0300) { /* All of these instructions use the mod/rm byte to get a data address */ if ((addr_modes.default_mode & SIXTEEN) ^ (addr_modes.override.address_size == ADDR_SIZE_PREFIX)) data_address = FPU_get_address_16(FPU_modrm, &FPU_EIP, &data_sel_off, addr_modes); else data_address = FPU_get_address(FPU_modrm, &FPU_EIP, &data_sel_off, addr_modes); if (addr_modes.default_mode) { if (FPU_EIP - 1 > code_limit) math_abort(FPU_info, SIGSEGV); } if (!(byte1 & 1)) { unsigned short status1 = partial_status; st0_ptr = &st(0); st0_tag = FPU_gettag0(); /* Stack underflow has priority */ if (NOT_EMPTY_ST0) { if (addr_modes.default_mode & PROTECTED) { /* This table works for 16 and 32 bit protected mode */ if (access_limit < data_sizes_16[(byte1 >> 1) & 3]) math_abort(FPU_info, SIGSEGV); } unmasked = 0; /* Do this here to stop compiler warnings. */ switch ((byte1 >> 1) & 3) { case 0: unmasked = FPU_load_single((float __user *) data_address, &loaded_data); loaded_tag = unmasked & 0xff; unmasked &= ~0xff; break; case 1: loaded_tag = FPU_load_int32((long __user *) data_address, &loaded_data); break; case 2: unmasked = FPU_load_double((double __user *) data_address, &loaded_data); loaded_tag = unmasked & 0xff; unmasked &= ~0xff; break; case 3: default: /* Used here to suppress gcc warnings. */ loaded_tag = FPU_load_int16((short __user *) data_address, &loaded_data); break; } /* No more access to user memory, it is safe to use static data now */ /* NaN operands have the next priority. */ /* We have to delay looking at st(0) until after loading the data, because that data might contain an SNaN */ if (((st0_tag == TAG_Special) && isNaN(st0_ptr)) || ((loaded_tag == TAG_Special) && isNaN(&loaded_data))) { /* Restore the status word; we might have loaded a denormal. */ partial_status = status1; if ((FPU_modrm & 0x30) == 0x10) { /* fcom or fcomp */ EXCEPTION(EX_Invalid); setcc(SW_C3 | SW_C2 | SW_C0); if ((FPU_modrm & 0x08) && (control_word & CW_Invalid)) FPU_pop(); /* fcomp, masked, so we pop. */ } else { if (loaded_tag == TAG_Special) loaded_tag = FPU_Special (&loaded_data); #ifdef PECULIAR_486 /* This is not really needed, but gives behaviour identical to an 80486 */ if ((FPU_modrm & 0x28) == 0x20) /* fdiv or fsub */ real_2op_NaN (&loaded_data, loaded_tag, 0, &loaded_data); else #endif /* PECULIAR_486 */ /* fadd, fdivr, fmul, or fsubr */ real_2op_NaN (&loaded_data, loaded_tag, 0, st0_ptr); } goto reg_mem_instr_done; } if (unmasked && !((FPU_modrm & 0x30) == 0x10)) { /* Is not a comparison instruction. */ if ((FPU_modrm & 0x38) == 0x38) { /* fdivr */ if ((st0_tag == TAG_Zero) && ((loaded_tag == TAG_Valid) || (loaded_tag == TAG_Special && isdenormal (&loaded_data)))) { if (FPU_divide_by_zero (0, getsign (&loaded_data)) < 0) { /* We use the fact here that the unmasked exception in the loaded data was for a denormal operand */ /* Restore the state of the denormal op bit */ partial_status &= ~SW_Denorm_Op; partial_status |= status1 & SW_Denorm_Op; } else setsign(st0_ptr, getsign (&loaded_data)); } } goto reg_mem_instr_done; } switch ((FPU_modrm >> 3) & 7) { case 0: /* fadd */ clear_C1(); FPU_add(&loaded_data, loaded_tag, 0, control_word); break; case 1: /* fmul */ clear_C1(); FPU_mul(&loaded_data, loaded_tag, 0, control_word); break; case 2: /* fcom */ FPU_compare_st_data(&loaded_data, loaded_tag); break; case 3: /* fcomp */ if (!FPU_compare_st_data (&loaded_data, loaded_tag) && !unmasked) FPU_pop(); break; case 4: /* fsub */ clear_C1(); FPU_sub(LOADED | loaded_tag, (int)&loaded_data, control_word); break; case 5: /* fsubr */ clear_C1(); FPU_sub(REV | LOADED | loaded_tag, (int)&loaded_data, control_word); break; case 6: /* fdiv */ clear_C1(); FPU_div(LOADED | loaded_tag, (int)&loaded_data, control_word); break; case 7: /* fdivr */ clear_C1(); if (st0_tag == TAG_Zero) partial_status = status1; /* Undo any denorm tag, zero-divide has priority. */ FPU_div(REV | LOADED | loaded_tag, (int)&loaded_data, control_word); break; } } else { if ((FPU_modrm & 0x30) == 0x10) { /* The instruction is fcom or fcomp */ EXCEPTION(EX_StackUnder); setcc(SW_C3 | SW_C2 | SW_C0); if ((FPU_modrm & 0x08) && (control_word & CW_Invalid)) FPU_pop(); /* fcomp */ } else FPU_stack_underflow(); } reg_mem_instr_done: operand_address = data_sel_off; } else { if (!(no_ip_update = FPU_load_store(((FPU_modrm & 0x38) | (byte1 & 6)) >> 1, addr_modes, data_address))) { operand_address = data_sel_off; } } } else { /* None of these instructions access user memory */ u_char instr_index = (FPU_modrm & 0x38) | (byte1 & 7); #ifdef PECULIAR_486 /* This is supposed to be undefined, but a real 80486 seems to do this: */ operand_address.offset = 0; operand_address.selector = FPU_DS; #endif /* PECULIAR_486 */ st0_ptr = &st(0); st0_tag = FPU_gettag0(); switch (type_table[(int)instr_index]) { case _NONE_: /* also _REGIc: _REGIn */ break; case _REG0_: if (!NOT_EMPTY_ST0) { FPU_stack_underflow(); goto FPU_instruction_done; } break; case _REGIi: if (!NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm)) { FPU_stack_underflow_i(FPU_rm); goto FPU_instruction_done; } break; case _REGIp: if (!NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm)) { FPU_stack_underflow_pop(FPU_rm); goto FPU_instruction_done; } break; case _REGI_: if (!NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm)) { FPU_stack_underflow(); goto FPU_instruction_done; } break; case _PUSH_: /* Only used by the fld st(i) instruction */ break; case _null_: FPU_illegal(); goto FPU_instruction_done; default: EXCEPTION(EX_INTERNAL | 0x111); goto FPU_instruction_done; } (*st_instr_table[(int)instr_index]) (); FPU_instruction_done: ; } if (!no_ip_update) instruction_address = entry_sel_off; FPU_fwait_done: #ifdef DEBUG RE_ENTRANT_CHECK_OFF; FPU_printall(); RE_ENTRANT_CHECK_ON; #endif /* DEBUG */ if (FPU_lookahead && !need_resched()) { FPU_ORIG_EIP = FPU_EIP - code_base; if (valid_prefix(&byte1, (u_char __user **) & FPU_EIP, &addr_modes.override)) goto do_another_FPU_instruction; } if (addr_modes.default_mode) FPU_EIP -= code_base; RE_ENTRANT_CHECK_OFF; } /* Support for prefix bytes is not yet complete. To properly handle all prefix bytes, further changes are needed in the emulator code which accesses user address space. Access to separate segments is important for msdos emulation. */ static int valid_prefix(u_char *Byte, u_char __user **fpu_eip, overrides * override) { u_char byte; u_char __user *ip = *fpu_eip; *override = (overrides) { 0, 0, PREFIX_DEFAULT}; /* defaults */ RE_ENTRANT_CHECK_OFF; FPU_code_access_ok(1); FPU_get_user(byte, ip); RE_ENTRANT_CHECK_ON; while (1) { switch (byte) { case ADDR_SIZE_PREFIX: override->address_size = ADDR_SIZE_PREFIX; goto do_next_byte; case OP_SIZE_PREFIX: override->operand_size = OP_SIZE_PREFIX; goto do_next_byte; case PREFIX_CS: override->segment = PREFIX_CS_; goto do_next_byte; case PREFIX_ES: override->segment = PREFIX_ES_; goto do_next_byte; case PREFIX_SS: override->segment = PREFIX_SS_; goto do_next_byte; case PREFIX_FS: override->segment = PREFIX_FS_; goto do_next_byte; case PREFIX_GS: override->segment = PREFIX_GS_; goto do_next_byte; case PREFIX_DS: override->segment = PREFIX_DS_; goto do_next_byte; /* lock is not a valid prefix for FPU instructions, let the cpu handle it to generate a SIGILL. */ /* case PREFIX_LOCK: */ /* rep.. prefixes have no meaning for FPU instructions */ case PREFIX_REPE: case PREFIX_REPNE: do_next_byte: ip++; RE_ENTRANT_CHECK_OFF; FPU_code_access_ok(1); FPU_get_user(byte, ip); RE_ENTRANT_CHECK_ON; break; case FWAIT_OPCODE: *Byte = byte; return 1; default: if ((byte & 0xf8) == 0xd8) { *Byte = byte; *fpu_eip = ip; return 1; } else { /* Not a valid sequence of prefix bytes followed by an FPU instruction. */ *Byte = byte; /* Needed for error message. */ return 0; } } } } void math_abort(struct math_emu_info *info, unsigned int signal) { FPU_EIP = FPU_ORIG_EIP; current->thread.trap_nr = X86_TRAP_MF; current->thread.error_code = 0; send_sig(signal, current, 1); RE_ENTRANT_CHECK_OFF; __asm__("movl %0,%%esp ; ret": :"g"(((long)info) - 4)); #ifdef PARANOID printk("ERROR: wm-FPU-emu math_abort failed!\n"); #endif /* PARANOID */ } #define S387 ((struct swregs_state *)s387) #define sstatus_word() \ ((S387->swd & ~SW_Top & 0xffff) | ((S387->ftop << SW_Top_Shift) & SW_Top)) int fpregs_soft_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { struct swregs_state *s387 = &target->thread.fpu.fpstate->regs.soft; void *space = s387->st_space; int ret; int offset, other, i, tags, regnr, tag, newtop; RE_ENTRANT_CHECK_OFF; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, s387, 0, offsetof(struct swregs_state, st_space)); RE_ENTRANT_CHECK_ON; if (ret) return ret; S387->ftop = (S387->swd >> SW_Top_Shift) & 7; offset = (S387->ftop & 7) * 10; other = 80 - offset; RE_ENTRANT_CHECK_OFF; /* Copy all registers in stack order. */ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, space + offset, 0, other); if (!ret && offset) ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, space, 0, offset); RE_ENTRANT_CHECK_ON; /* The tags may need to be corrected now. */ tags = S387->twd; newtop = S387->ftop; for (i = 0; i < 8; i++) { regnr = (i + newtop) & 7; if (((tags >> ((regnr & 7) * 2)) & 3) != TAG_Empty) { /* The loaded data over-rides all other cases. */ tag = FPU_tagof((FPU_REG *) ((u_char *) S387->st_space + 10 * regnr)); tags &= ~(3 << (regnr * 2)); tags |= (tag & 3) << (regnr * 2); } } S387->twd = tags; return ret; } int fpregs_soft_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { struct swregs_state *s387 = &target->thread.fpu.fpstate->regs.soft; const void *space = s387->st_space; int offset = (S387->ftop & 7) * 10, other = 80 - offset; RE_ENTRANT_CHECK_OFF; #ifdef PECULIAR_486 S387->cwd &= ~0xe080; /* An 80486 sets nearly all of the reserved bits to 1. */ S387->cwd |= 0xffff0040; S387->swd = sstatus_word() | 0xffff0000; S387->twd |= 0xffff0000; S387->fcs &= ~0xf8000000; S387->fos |= 0xffff0000; #endif /* PECULIAR_486 */ membuf_write(&to, s387, offsetof(struct swregs_state, st_space)); membuf_write(&to, space + offset, other); membuf_write(&to, space, offset); RE_ENTRANT_CHECK_ON; return 0; } |