arch/i386/math-emu/reg

/* */
   1         .file "reg_round.S"
   2 /*---------------------------------------------------------------------------+
   3  |  reg_round.S                                                              |
   4  |                                                                           |
   5  | Rounding/truncation/etc for FPU basic arithmetic functions.               |
   6  |                                                                           |
   7  | Copyright (C) 1993                                                        |
   8  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   9  |                       Australia.  E-mail   billm@vaxc.cc.monash.edu.au    |
  10  |                                                                           |
  11  | This code has four possible entry points.                                 |
  12  | The following must be entered by a jmp instruction:                       |
  13  |   fpu_reg_round, fpu_reg_round_sqrt, and fpu_Arith_exit.                  |
  14  |                                                                           |
  15  | The _round_reg entry point is intended to be used by C code.              |
  16  | From C, call as:                                                          |
  17  | void round_reg(FPU_REG *arg, unsigned int extent, unsigned int control_w) |
  18  |                                                                           |
  19  | For correct "up" and "down" rounding, the argument must have the correct  |
  20  | sign.                                                                     |
  21  |                                                                           |
  22  +---------------------------------------------------------------------------*/
  23 
  24 /*---------------------------------------------------------------------------+
  25  | Four entry points.                                                        |
  26  |                                                                           |
  27  | Needed by both the fpu_reg_round and fpu_reg_round_sqrt entry points:     |
  28  |  %eax:%ebx  64 bit significand                                            |
  29  |  %edx       32 bit extension of the significand                           |
  30  |  %edi       pointer to an FPU_REG for the result to be stored             |
  31  |  stack      calling function must have set up a C stack frame and         |
  32  |             pushed %esi, %edi, and %ebx                                   |
  33  |                                                                           |
  34  | Needed just for the fpu_reg_round_sqrt entry point:                       |
  35  |  %cx  A control word in the same format as the FPU control word.          |
  36  | Otherwise, PARAM4 must give such a value.                                 |
  37  |                                                                           |
  38  |                                                                           |
  39  | The significand and its extension are assumed to be exact in the          |
  40  | following sense:                                                          |
  41  |   If the significand by itself is the exact result then the significand   |
  42  |   extension (%edx) must contain 0, otherwise the significand extension    |
  43  |   must be non-zero.                                                       |
  44  |   If the significand extension is non-zero then the significand is        |
  45  |   smaller than the magnitude of the correct exact result by an amount     |
  46  |   greater than zero and less than one ls bit of the significand.          |
  47  |   The significand extension is only required to have three possible       |
  48  |   non-zero values:                                                        |
  49  |       less than 0x80000000  <=> the significand is less than 1/2 an ls    |
  50  |                                 bit smaller than the magnitude of the     |
  51  |                                 true exact result.                        |
  52  |         exactly 0x80000000  <=> the significand is exactly 1/2 an ls bit  |
  53  |                                 smaller than the magnitude of the true    |
  54  |                                 exact result.                             |
  55  |    greater than 0x80000000  <=> the significand is more than 1/2 an ls    |
  56  |                                 bit smaller than the magnitude of the     |
  57  |                                 true exact result.                        |
  58  |                                                                           |
  59  +---------------------------------------------------------------------------*/
  60 
  61 /*---------------------------------------------------------------------------+
  62  |  The code in this module has become quite complex, but it should handle   |
  63  |  all of the FPU flags which are set at this stage of the basic arithmetic |
  64  |  computations.                                                            |
  65  |  There are a few rare cases where the results are not set identically to  |
  66  |  a real FPU. These require a bit more thought because at this stage the   |
  67  |  results of the code here appear to be more consistent...                 |
  68  |  This may be changed in a future version.                                 |
  69  +---------------------------------------------------------------------------*/
  70 
  71 
  72 #include "fpu_asm.h"
  73 #include "exception.h"
  74 #include "control_w.h"
  75 
  76 /* Flags for FPU_bits_lost */
  77 #define LOST_DOWN       $1
  78 #define LOST_UP         $2
  79 
  80 /* Flags for FPU_denormal */
  81 #define DENORMAL        $1
  82 #define UNMASKED_UNDERFLOW $2
  83 
  84 
  85 #ifndef NON_REENTRANT_FPU
  86 /*      Make the code re-entrant by putting
  87         local storage on the stack: */
  88 #define FPU_bits_lost   (%esp)
  89 #define FPU_denormal    1(%esp)
  90 
  91 #else
  92 /*      Not re-entrant, so we can gain speed by putting
  93         local storage in a static area: */
  94 .data
  95         .align 2,0
  96 FPU_bits_lost:
  97         .byte   0
  98 FPU_denormal:
  99         .byte   0
 100 #endif NON_REENTRANT_FPU
 101 
 102 
 103 .text
 104         .align 2,144
 105 .globl fpu_reg_round
 106 .globl fpu_reg_round_sqrt
 107 .globl fpu_Arith_exit
 108 .globl _round_reg
 109 
 110 /* Entry point when called from C */
 111 _round_reg:
 112         pushl   %ebp
 113         movl    %esp,%ebp
 114         pushl   %esi
 115         pushl   %edi
 116         pushl   %ebx
 117 
 118         movl    PARAM1,%edi
 119         movl    SIGH(%edi),%eax
 120         movl    SIGL(%edi),%ebx
 121         movl    PARAM2,%edx
 122         movl    PARAM3,%ecx
 123         jmp     fpu_reg_round_sqrt
 124 
 125 fpu_reg_round:                  /* Normal entry point */
 126         movl    PARAM4,%ecx
 127 
 128 fpu_reg_round_sqrt:             /* Entry point from wm_sqrt.S */
 129 
 130 #ifndef NON_REENTRANT_FPU
 131         pushl   %ebx            /* adjust the stack pointer */
 132 #endif NON_REENTRANT_FPU
 133 
 134 #ifdef PARANOID
 135 /* Cannot use this here yet */
 136 /*      orl     %eax,%eax */
 137 /*      jns     L_entry_bugged */
 138 #endif PARANOID
 139 
 140         cmpl    EXP_UNDER,EXP(%edi)
 141         jle     xMake_denorm                    /* The number is a de-normal */
 142 
 143         movb    $0,FPU_denormal                 /* 0 -> not a de-normal */
 144 
 145 xDenorm_done:
 146         movb    $0,FPU_bits_lost                /* No bits yet lost in rounding */
 147 
 148         movl    %ecx,%esi
 149         andl    CW_PC,%ecx
 150         cmpl    PR_64_BITS,%ecx
 151         je      LRound_To_64
 152 
 153         cmpl    PR_53_BITS,%ecx
 154         je      LRound_To_53
 155 
 156         cmpl    PR_24_BITS,%ecx
 157         je      LRound_To_24
 158 
 159 #ifdef PECULIAR_486
 160 /* With the precision control bits set to 01 "(reserved)", a real 80486
 161    behaves as if the precision control bits were set to 11 "64 bits" */
 162         cmpl    PR_RESERVED_BITS,%ecx
 163         je      LRound_To_64
 164 #ifdef PARANOID
 165         jmp     L_bugged_denorm_486
 166 #endif PARANOID
 167 #else
 168 #ifdef PARANOID
 169         jmp     L_bugged_denorm /* There is no bug, just a bad control word */
 170 #endif PARANOID
 171 #endif PECULIAR_486
 172 
 173 
 174 /* Round etc to 24 bit precision */
 175 LRound_To_24:
 176         movl    %esi,%ecx
 177         andl    CW_RC,%ecx
 178         cmpl    RC_RND,%ecx
 179         je      LRound_nearest_24
 180 
 181         cmpl    RC_CHOP,%ecx
 182         je      LCheck_truncate_24
 183 
 184         cmpl    RC_UP,%ecx              /* Towards +infinity */
 185         je      LUp_24
 186 
 187         cmpl    RC_DOWN,%ecx            /* Towards -infinity */
 188         je      LDown_24
 189 
 190 #ifdef PARANOID
 191         jmp     L_bugged_round24
 192 #endif PARANOID
 193 
 194 LUp_24:
 195         cmpb    SIGN_POS,SIGN(%edi)
 196         jne     LCheck_truncate_24      /* If negative then  up==truncate */
 197 
 198         jmp     LCheck_24_round_up
 199 
 200 LDown_24:
 201         cmpb    SIGN_POS,SIGN(%edi)
 202         je      LCheck_truncate_24      /* If positive then  down==truncate */
 203 
 204 LCheck_24_round_up:
 205         movl    %eax,%ecx
 206         andl    $0x000000ff,%ecx
 207         orl     %ebx,%ecx
 208         orl     %edx,%ecx
 209         jnz     LDo_24_round_up
 210         jmp     LRe_normalise
 211 
 212 LRound_nearest_24:
 213         /* Do rounding of the 24th bit if needed (nearest or even) */
 214         movl    %eax,%ecx
 215         andl    $0x000000ff,%ecx
 216         cmpl    $0x00000080,%ecx
 217         jc      LCheck_truncate_24      /* less than half, no increment needed */
 218 
 219         jne     LGreater_Half_24        /* greater than half, increment needed */
 220 
 221         /* Possibly half, we need to check the ls bits */
 222         orl     %ebx,%ebx
 223         jnz     LGreater_Half_24        /* greater than half, increment needed */
 224 
 225         orl     %edx,%edx
 226         jnz     LGreater_Half_24        /* greater than half, increment needed */
 227 
 228         /* Exactly half, increment only if 24th bit is 1 (round to even) */
 229         testl   $0x00000100,%eax
 230         jz      LDo_truncate_24
 231 
 232 LGreater_Half_24:                       /* Rounding: increment at the 24th bit */
 233 LDo_24_round_up:
 234         andl    $0xffffff00,%eax        /* Truncate to 24 bits */
 235         xorl    %ebx,%ebx
 236         movb    LOST_UP,FPU_bits_lost
 237         addl    $0x00000100,%eax
 238         jmp     LCheck_Round_Overflow
 239 
 240 LCheck_truncate_24:
 241         movl    %eax,%ecx
 242         andl    $0x000000ff,%ecx
 243         orl     %ebx,%ecx
 244         orl     %edx,%ecx
 245         jz      LRe_normalise           /* No truncation needed */
 246 
 247 LDo_truncate_24:
 248         andl    $0xffffff00,%eax        /* Truncate to 24 bits */
 249         xorl    %ebx,%ebx
 250         movb    LOST_DOWN,FPU_bits_lost
 251         jmp     LRe_normalise
 252 
 253 
 254 /* Round etc to 53 bit precision */
 255 LRound_To_53:
 256         movl    %esi,%ecx
 257         andl    CW_RC,%ecx
 258         cmpl    RC_RND,%ecx
 259         je      LRound_nearest_53
 260 
 261         cmpl    RC_CHOP,%ecx
 262         je      LCheck_truncate_53
 263 
 264         cmpl    RC_UP,%ecx              /* Towards +infinity */
 265         je      LUp_53
 266 
 267         cmpl    RC_DOWN,%ecx            /* Towards -infinity */
 268         je      LDown_53
 269 
 270 #ifdef PARANOID
 271         jmp     L_bugged_round53
 272 #endif PARANOID
 273 
 274 LUp_53:
 275         cmpb    SIGN_POS,SIGN(%edi)
 276         jne     LCheck_truncate_53      /* If negative then  up==truncate */
 277 
 278         jmp     LCheck_53_round_up
 279 
 280 LDown_53:
 281         cmpb    SIGN_POS,SIGN(%edi)
 282         je      LCheck_truncate_53      /* If positive then  down==truncate */
 283 
 284 LCheck_53_round_up:
 285         movl    %ebx,%ecx
 286         andl    $0x000007ff,%ecx
 287         orl     %edx,%ecx
 288         jnz     LDo_53_round_up
 289         jmp     LRe_normalise
 290 
 291 LRound_nearest_53:
 292         /* Do rounding of the 53rd bit if needed (nearest or even) */
 293         movl    %ebx,%ecx
 294         andl    $0x000007ff,%ecx
 295         cmpl    $0x00000400,%ecx
 296         jc      LCheck_truncate_53      /* less than half, no increment needed */
 297 
 298         jnz     LGreater_Half_53        /* greater than half, increment needed */
 299 
 300         /* Possibly half, we need to check the ls bits */
 301         orl     %edx,%edx
 302         jnz     LGreater_Half_53        /* greater than half, increment needed */
 303 
 304         /* Exactly half, increment only if 53rd bit is 1 (round to even) */
 305         testl   $0x00000800,%ebx
 306         jz      LTruncate_53
 307 
 308 LGreater_Half_53:                       /* Rounding: increment at the 53rd bit */
 309 LDo_53_round_up:
 310         movb    LOST_UP,FPU_bits_lost
 311         andl    $0xfffff800,%ebx        /* Truncate to 53 bits */
 312         addl    $0x00000800,%ebx
 313         adcl    $0,%eax
 314         jmp     LCheck_Round_Overflow
 315 
 316 LCheck_truncate_53:
 317         movl    %ebx,%ecx
 318         andl    $0x000007ff,%ecx
 319         orl     %edx,%ecx
 320         jz      LRe_normalise
 321 
 322 LTruncate_53:
 323         movb    LOST_DOWN,FPU_bits_lost
 324         andl    $0xfffff800,%ebx        /* Truncate to 53 bits */
 325         jmp     LRe_normalise
 326 
 327 
 328 /* Round etc to 64 bit precision */
 329 LRound_To_64:
 330         movl    %esi,%ecx
 331         andl    CW_RC,%ecx
 332         cmpl    RC_RND,%ecx
 333         je      LRound_nearest_64
 334 
 335         cmpl    RC_CHOP,%ecx
 336         je      LCheck_truncate_64
 337 
 338         cmpl    RC_UP,%ecx              /* Towards +infinity */
 339         je      LUp_64
 340 
 341         cmpl    RC_DOWN,%ecx            /* Towards -infinity */
 342         je      LDown_64
 343 
 344 #ifdef PARANOID
 345         jmp     L_bugged_round64
 346 #endif PARANOID
 347 
 348 LUp_64:
 349         cmpb    SIGN_POS,SIGN(%edi)
 350         jne     LCheck_truncate_64      /* If negative then  up==truncate */
 351 
 352         orl     %edx,%edx
 353         jnz     LDo_64_round_up
 354         jmp     LRe_normalise
 355 
 356 LDown_64:
 357         cmpb    SIGN_POS,SIGN(%edi)
 358         je      LCheck_truncate_64      /* If positive then  down==truncate */
 359 
 360         orl     %edx,%edx
 361         jnz     LDo_64_round_up
 362         jmp     LRe_normalise
 363 
 364 LRound_nearest_64:
 365         cmpl    $0x80000000,%edx
 366         jc      LCheck_truncate_64
 367 
 368         jne     LDo_64_round_up
 369 
 370         /* Now test for round-to-even */
 371         testb   $1,%ebx
 372         jz      LCheck_truncate_64
 373 
 374 LDo_64_round_up:
 375         movb    LOST_UP,FPU_bits_lost
 376         addl    $1,%ebx
 377         adcl    $0,%eax
 378 
 379 LCheck_Round_Overflow:
 380         jnc     LRe_normalise
 381 
 382         /* Overflow, adjust the result (significand to 1.0) */
 383         rcrl    $1,%eax
 384         rcrl    $1,%ebx
 385         incl    EXP(%edi)
 386         jmp     LRe_normalise
 387 
 388 LCheck_truncate_64:
 389         orl     %edx,%edx
 390         jz      LRe_normalise
 391 
 392 LTruncate_64:
 393         movb    LOST_DOWN,FPU_bits_lost
 394 
 395 LRe_normalise:
 396         testb   $0xff,FPU_denormal
 397         jnz     xNormalise_result
 398 
 399 xL_Normalised:
 400         cmpb    LOST_UP,FPU_bits_lost
 401         je      xL_precision_lost_up
 402 
 403         cmpb    LOST_DOWN,FPU_bits_lost
 404         je      xL_precision_lost_down
 405 
 406 xL_no_precision_loss:
 407         /* store the result */
 408         movb    TW_Valid,TAG(%edi)
 409 
 410 xL_Store_significand:
 411         movl    %eax,SIGH(%edi)
 412         movl    %ebx,SIGL(%edi)
 413 
 414         xorl    %eax,%eax       /* No errors detected. */
 415 
 416         cmpl    EXP_OVER,EXP(%edi)
 417         jge     L_overflow
 418 
 419 fpu_reg_round_exit:
 420 #ifndef NON_REENTRANT_FPU
 421         popl    %ebx            /* adjust the stack pointer */
 422 #endif NON_REENTRANT_FPU
 423 
 424 fpu_Arith_exit:
 425         popl    %ebx
 426         popl    %edi
 427         popl    %esi
 428         leave
 429         ret
 430 
 431 
 432 /*
 433  * Set the FPU status flags to represent precision loss due to
 434  * round-up.
 435  */
 436 xL_precision_lost_up:
 437         push    %eax
 438         call    _set_precision_flag_up
 439         popl    %eax
 440         jmp     xL_no_precision_loss
 441 
 442 /*
 443  * Set the FPU status flags to represent precision loss due to
 444  * truncation.
 445  */
 446 xL_precision_lost_down:
 447         push    %eax
 448         call    _set_precision_flag_down
 449         popl    %eax
 450         jmp     xL_no_precision_loss
 451 
 452 
 453 /*
 454  * The number is a denormal (which might get rounded up to a normal)
 455  * Shift the number right the required number of bits, which will
 456  * have to be undone later...
 457  */
 458 xMake_denorm:
 459         /* The action to be taken depends upon whether the underflow
 460            exception is masked */
 461         testb   CW_Underflow,%cl                /* Underflow mask. */
 462         jz      xUnmasked_underflow             /* Do not make a denormal. */
 463 
 464         movb    DENORMAL,FPU_denormal
 465 
 466         pushl   %ecx            /* Save */
 467         movl    EXP_UNDER+1,%ecx
 468         subl    EXP(%edi),%ecx
 469 
 470         cmpl    $64,%ecx        /* shrd only works for 0..31 bits */
 471         jnc     xDenorm_shift_more_than_63
 472 
 473         cmpl    $32,%ecx        /* shrd only works for 0..31 bits */
 474         jnc     xDenorm_shift_more_than_32
 475 
 476 /*
 477  * We got here without jumps by assuming that the most common requirement
 478  *   is for a small de-normalising shift.
 479  * Shift by [1..31] bits
 480  */
 481         addl    %ecx,EXP(%edi)
 482         orl     %edx,%edx       /* extension */
 483         setne   %ch             /* Save whether %edx is non-zero */
 484         xorl    %edx,%edx
 485         shrd    %cl,%ebx,%edx
 486         shrd    %cl,%eax,%ebx
 487         shr     %cl,%eax
 488         orb     %ch,%dl
 489         popl    %ecx
 490         jmp     xDenorm_done
 491 
 492 /* Shift by [32..63] bits */
 493 xDenorm_shift_more_than_32:
 494         addl    %ecx,EXP(%edi)
 495         subb    $32,%cl
 496         orl     %edx,%edx
 497         setne   %ch
 498         orb     %ch,%bl
 499         xorl    %edx,%edx
 500         shrd    %cl,%ebx,%edx
 501         shrd    %cl,%eax,%ebx
 502         shr     %cl,%eax
 503         orl     %edx,%edx               /* test these 32 bits */
 504         setne   %cl
 505         orb     %ch,%bl
 506         orb     %cl,%bl
 507         movl    %ebx,%edx
 508         movl    %eax,%ebx
 509         xorl    %eax,%eax
 510         popl    %ecx
 511         jmp     xDenorm_done
 512 
 513 /* Shift by [64..) bits */
 514 xDenorm_shift_more_than_63:
 515         cmpl    $64,%ecx
 516         jne     xDenorm_shift_more_than_64
 517 
 518 /* Exactly 64 bit shift */
 519         addl    %ecx,EXP(%edi)
 520         xorl    %ecx,%ecx
 521         orl     %edx,%edx
 522         setne   %cl
 523         orl     %ebx,%ebx
 524         setne   %ch
 525         orb     %ch,%cl
 526         orb     %cl,%al
 527         movl    %eax,%edx
 528         xorl    %eax,%eax
 529         xorl    %ebx,%ebx
 530         popl    %ecx
 531         jmp     xDenorm_done
 532 
 533 xDenorm_shift_more_than_64:
 534         movl    EXP_UNDER+1,EXP(%edi)
 535 /* This is easy, %eax must be non-zero, so.. */
 536         movl    $1,%edx
 537         xorl    %eax,%eax
 538         xorl    %ebx,%ebx
 539         popl    %ecx
 540         jmp     xDenorm_done
 541 
 542 
 543 xUnmasked_underflow:
 544         movb    UNMASKED_UNDERFLOW,FPU_denormal
 545         jmp     xDenorm_done
 546 
 547 
 548 /* Undo the de-normalisation. */
 549 xNormalise_result:
 550         cmpb    UNMASKED_UNDERFLOW,FPU_denormal
 551         je      xSignal_underflow
 552 
 553 /* The number must be a denormal if we got here. */
 554 #ifdef PARANOID
 555         /* But check it... just in case. */
 556         cmpl    EXP_UNDER+1,EXP(%edi)
 557         jne     L_norm_bugged
 558 #endif PARANOID
 559 
 560 #ifdef PECULIAR_486
 561         /*
 562          * This implements a special feature of 80486 behaviour.
 563          * Underflow will be signalled even if the number is
 564          * not a denormal after rounding.
 565          * This difference occurs only for masked underflow, and not
 566          * in the unmasked case.
 567          * Actual 80486 behaviour differs from this in some circumstances.
 568          */
 569         orl     %eax,%eax               /* ms bits */
 570         js      LNormalise_shift_done   /* Will be masked underflow */
 571 #endif PECULIAR_486
 572 
 573         orl     %eax,%eax               /* ms bits */
 574         js      xL_Normalised           /* No longer a denormal */
 575 
 576         jnz     LNormalise_shift_up_to_31       /* Shift left 0 - 31 bits */
 577 
 578         orl     %ebx,%ebx
 579         jz      L_underflow_to_zero     /* The contents are zero */
 580 
 581 /* Shift left 32 - 63 bits */
 582         movl    %ebx,%eax
 583         xorl    %ebx,%ebx
 584         subl    $32,EXP(%edi)
 585 
 586 LNormalise_shift_up_to_31:
 587         bsrl    %eax,%ecx       /* get the required shift in %ecx */
 588         subl    $31,%ecx
 589         negl    %ecx
 590         shld    %cl,%ebx,%eax
 591         shl     %cl,%ebx
 592         subl    %ecx,EXP(%edi)
 593 
 594 LNormalise_shift_done:
 595         testb   $0xff,FPU_bits_lost     /* bits lost == underflow */
 596         jz      xL_Normalised
 597 
 598         /* There must be a masked underflow */
 599         push    %eax
 600         pushl   EX_Underflow
 601         call    _exception
 602         popl    %eax
 603         popl    %eax
 604         jmp     xL_Normalised
 605 
 606 
 607 /*
 608  * The operations resulted in a number too small to represent.
 609  * Masked response.
 610  */
 611 L_underflow_to_zero:
 612         push    %eax
 613         call    _set_precision_flag_down
 614         popl    %eax
 615 
 616         push    %eax
 617         pushl   EX_Underflow
 618         call    _exception
 619         popl    %eax
 620         popl    %eax
 621 
 622 /* Reduce the exponent to EXP_UNDER */
 623         movl    EXP_UNDER,EXP(%edi)
 624         movb    TW_Zero,TAG(%edi)
 625         jmp     xL_Store_significand
 626 
 627 
 628 /* The operations resulted in a number too large to represent. */
 629 L_overflow:
 630         push    %edi
 631         call    _arith_overflow
 632         pop     %edi
 633         jmp     fpu_reg_round_exit
 634 
 635 
 636 xSignal_underflow:
 637         /* The number may have been changed to a non-denormal */
 638         /* by the rounding operations. */
 639         cmpl    EXP_UNDER,EXP(%edi)
 640         jle     xDo_unmasked_underflow
 641 
 642         jmp     xL_Normalised
 643 
 644 xDo_unmasked_underflow:
 645         /* Increase the exponent by the magic number */
 646         addl    $(3*(1<<13)),EXP(%edi)
 647         push    %eax
 648         pushl   EX_Underflow
 649         call    EXCEPTION
 650         popl    %eax
 651         popl    %eax
 652         jmp     xL_Normalised
 653 
 654 
 655 #ifdef PARANOID
 656 #ifdef PECULIAR_486
 657 L_bugged_denorm_486:
 658         pushl   EX_INTERNAL|0x236
 659         call    EXCEPTION
 660         popl    %ebx
 661         jmp     L_exception_exit
 662 #else
 663 L_bugged_denorm:
 664         pushl   EX_INTERNAL|0x230
 665         call    EXCEPTION
 666         popl    %ebx
 667         jmp     L_exception_exit
 668 #endif PECULIAR_486
 669 
 670 L_bugged_round24:
 671         pushl   EX_INTERNAL|0x231
 672         call    EXCEPTION
 673         popl    %ebx
 674         jmp     L_exception_exit
 675 
 676 L_bugged_round53:
 677         pushl   EX_INTERNAL|0x232
 678         call    EXCEPTION
 679         popl    %ebx
 680         jmp     L_exception_exit
 681 
 682 L_bugged_round64:
 683         pushl   EX_INTERNAL|0x233
 684         call    EXCEPTION
 685         popl    %ebx
 686         jmp     L_exception_exit
 687 
 688 L_norm_bugged:
 689         pushl   EX_INTERNAL|0x234
 690         call    EXCEPTION
 691         popl    %ebx
 692         jmp     L_exception_exit
 693 
 694 L_entry_bugged:
 695         pushl   EX_INTERNAL|0x235
 696         call    EXCEPTION
 697         popl    %ebx
 698 L_exception_exit:
 699         mov     $1,%eax
 700         jmp     fpu_reg_round_exit
 701 #endif PARANOID
/* */
root/arch/i386/math-emu/reg_round.S
