arch/m68k/fpsp040/bugfix.S

   1 |
   2 |       bugfix.sa 3.2 1/31/91
   3 |
   4 |
   5 |       This file contains workarounds for bugs in the 040
   6 |       relating to the Floating-Point Software Package (FPSP)
   7 |
   8 |       Fixes for bugs: 1238
   9 |
  10 |       Bug: 1238
  11 |
  12 |
  13 |    /* The following dirty_bit clear should be left in
  14 |     * the handler permanently to improve throughput.
  15 |     * The dirty_bits are located at bits [23:16] in
  16 |     * longword $08 in the busy frame $4x60.  Bit 16
  17 |     * corresponds to FP0, bit 17 corresponds to FP1,
  18 |     * and so on.
  19 |     */
  20 |    if  (E3_exception_just_serviced)   {
  21 |         dirty_bit[cmdreg3b[9:7]] = 0;
  22 |         }
  23 |
  24 |    if  (fsave_format_version != $40)  {goto NOFIX}
  25 |
  26 |    if !(E3_exception_just_serviced)   {goto NOFIX}
  27 |    if  (cupc == 0000000)              {goto NOFIX}
  28 |    if  ((cmdreg1b[15:13] != 000) &&
  29 |         (cmdreg1b[15:10] != 010001))  {goto NOFIX}
  30 |    if (((cmdreg1b[15:13] != 000) || ((cmdreg1b[12:10] != cmdreg2b[9:7]) &&
  31 |                                     (cmdreg1b[12:10] != cmdreg3b[9:7]))  ) &&
  32 |        ((cmdreg1b[ 9: 7] != cmdreg2b[9:7]) &&
  33 |         (cmdreg1b[ 9: 7] != cmdreg3b[9:7])) )  {goto NOFIX}
  34 |
  35 |    /* Note: for 6d43b or 8d43b, you may want to add the following code
  36 |     * to get better coverage.  (If you do not insert this code, the part
  37 |     * won't lock up; it will simply get the wrong answer.)
  38 |     * Do NOT insert this code for 10d43b or later parts.
  39 |     *
  40 |     *  if (fpiarcu == integer stack return address) {
  41 |     *       cupc = 0000000;
  42 |     *       goto NOFIX;
  43 |     *       }
  44 |     */
  45 |
  46 |    if (cmdreg1b[15:13] != 000)   {goto FIX_OPCLASS2}
  47 |    FIX_OPCLASS0:
  48 |    if (((cmdreg1b[12:10] == cmdreg2b[9:7]) ||
  49 |        (cmdreg1b[ 9: 7] == cmdreg2b[9:7])) &&
  50 |       (cmdreg1b[12:10] != cmdreg3b[9:7]) &&
  51 |       (cmdreg1b[ 9: 7] != cmdreg3b[9:7]))  {  /* xu conflict only */
  52 |       /* We execute the following code if there is an
  53 |          xu conflict and NOT an nu conflict */
  54 |
  55 |       /* first save some values on the fsave frame */
  56 |       stag_temp     = STAG[fsave_frame];
  57 |       cmdreg1b_temp = CMDREG1B[fsave_frame];
  58 |       dtag_temp     = DTAG[fsave_frame];
  59 |       ete15_temp    = ETE15[fsave_frame];
  60 |
  61 |       CUPC[fsave_frame] = 0000000;
  62 |       FRESTORE
  63 |       FSAVE
  64 |
  65 |       /* If the xu instruction is exceptional, we punt.
  66 |        * Otherwise, we would have to include OVFL/UNFL handler
  67 |        * code here to get the correct answer.
  68 |        */
  69 |       if (fsave_frame_format == $4060) {goto KILL_PROCESS}
  70 |
  71 |       fsave_frame = /* build a long frame of all zeros */
  72 |       fsave_frame_format = $4060;  /* label it as long frame */
  73 |
  74 |       /* load it with the temps we saved */
  75 |       STAG[fsave_frame]     =  stag_temp;
  76 |       CMDREG1B[fsave_frame] =  cmdreg1b_temp;
  77 |       DTAG[fsave_frame]     =  dtag_temp;
  78 |       ETE15[fsave_frame]    =  ete15_temp;
  79 |
  80 |       /* Make sure that the cmdreg3b dest reg is not going to
  81 |        * be destroyed by a FMOVEM at the end of all this code.
  82 |        * If it is, you should move the current value of the reg
  83 |        * onto the stack so that the reg will loaded with that value.
  84 |        */
  85 |
  86 |       /* All done.  Proceed with the code below */
  87 |    }
  88 |
  89 |    etemp  = FP_reg_[cmdreg1b[12:10]];
  90 |    ete15  = ~ete14;
  91 |    cmdreg1b[15:10] = 010010;
  92 |    clear(bug_flag_procIDxxxx);
  93 |    FRESTORE and return;
  94 |
  95 |
  96 |    FIX_OPCLASS2:
  97 |    if ((cmdreg1b[9:7] == cmdreg2b[9:7]) &&
  98 |       (cmdreg1b[9:7] != cmdreg3b[9:7]))  {  /* xu conflict only */
  99 |       /* We execute the following code if there is an
 100 |          xu conflict and NOT an nu conflict */
 101 |
 102 |       /* first save some values on the fsave frame */
 103 |       stag_temp     = STAG[fsave_frame];
 104 |       cmdreg1b_temp = CMDREG1B[fsave_frame];
 105 |       dtag_temp     = DTAG[fsave_frame];
 106 |       ete15_temp    = ETE15[fsave_frame];
 107 |       etemp_temp    = ETEMP[fsave_frame];
 108 |
 109 |       CUPC[fsave_frame] = 0000000;
 110 |       FRESTORE
 111 |       FSAVE
 112 |
 113 |
 114 |       /* If the xu instruction is exceptional, we punt.
 115 |        * Otherwise, we would have to include OVFL/UNFL handler
 116 |        * code here to get the correct answer.
 117 |        */
 118 |       if (fsave_frame_format == $4060) {goto KILL_PROCESS}
 119 |
 120 |       fsave_frame = /* build a long frame of all zeros */
 121 |       fsave_frame_format = $4060;  /* label it as long frame */
 122 |
 123 |       /* load it with the temps we saved */
 124 |       STAG[fsave_frame]     =  stag_temp;
 125 |       CMDREG1B[fsave_frame] =  cmdreg1b_temp;
 126 |       DTAG[fsave_frame]     =  dtag_temp;
 127 |       ETE15[fsave_frame]    =  ete15_temp;
 128 |       ETEMP[fsave_frame]    =  etemp_temp;
 129 |
 130 |       /* Make sure that the cmdreg3b dest reg is not going to
 131 |        * be destroyed by a FMOVEM at the end of all this code.
 132 |        * If it is, you should move the current value of the reg
 133 |        * onto the stack so that the reg will loaded with that value.
 134 |        */
 135 |
 136 |       /* All done.  Proceed with the code below */
 137 |    }
 138 |
 139 |    if (etemp_exponent == min_sgl)   etemp_exponent = min_dbl;
 140 |    if (etemp_exponent == max_sgl)   etemp_exponent = max_dbl;
 141 |    cmdreg1b[15:10] = 010101;
 142 |    clear(bug_flag_procIDxxxx);
 143 |    FRESTORE and return;
 144 |
 145 |
 146 |    NOFIX:
 147 |    clear(bug_flag_procIDxxxx);
 148 |    FRESTORE and return;
 149 |
 150
 151
 152 |               Copyright (C) Motorola, Inc. 1990
 153 |                       All Rights Reserved
 154 |
 155 |       For details on the license for this file, please see the
 156 |       file, README, in this same directory.
 157
 158 |BUGFIX    idnt    2,1 | Motorola 040 Floating Point Software Package
 159
 160         |section        8
 161
 162 #include "fpsp.h"
 163
 164         |xref   fpsp_fmt_error
 165
 166         .global b1238_fix
 167 b1238_fix:
 168 |
 169 | This code is entered only on completion of the handling of an
 170 | nu-generated ovfl, unfl, or inex exception.  If the version
 171 | number of the fsave is not $40, this handler is not necessary.
 172 | Simply branch to fix_done and exit normally.
 173 |
 174         cmpib   #VER_40,4(%a7)
 175         bne     fix_done
 176 |
 177 | Test for cu_savepc equal to zero.  If not, this is not a bug
 178 | #1238 case.
 179 |
 180         moveb   CU_SAVEPC(%a6),%d0
 181         andib   #0xFE,%d0
 182         beq     fix_done        |if zero, this is not bug #1238
 183
 184 |
 185 | Test the register conflict aspect.  If opclass0, check for
 186 | cu src equal to xu dest or equal to nu dest.  If so, go to
 187 | op0.  Else, or if opclass2, check for cu dest equal to
 188 | xu dest or equal to nu dest.  If so, go to tst_opcl.  Else,
 189 | exit, it is not the bug case.
 190 |
 191 | Check for opclass 0.  If not, go and check for opclass 2 and sgl.
 192 |
 193         movew   CMDREG1B(%a6),%d0
 194         andiw   #0xE000,%d0             |strip all but opclass
 195         bne     op2sgl                  |not opclass 0, check op2
 196 |
 197 | Check for cu and nu register conflict.  If one exists, this takes
 198 | priority over a cu and xu conflict.
 199 |
 200         bfextu  CMDREG1B(%a6){#3:#3},%d0        |get 1st src
 201         bfextu  CMDREG3B(%a6){#6:#3},%d1        |get 3rd dest
 202         cmpb    %d0,%d1
 203         beqs    op0                     |if equal, continue bugfix
 204 |
 205 | Check for cu dest equal to nu dest.  If so, go and fix the
 206 | bug condition.  Otherwise, exit.
 207 |
 208         bfextu  CMDREG1B(%a6){#6:#3},%d0        |get 1st dest
 209         cmpb    %d0,%d1                 |cmp 1st dest with 3rd dest
 210         beqs    op0                     |if equal, continue bugfix
 211 |
 212 | Check for cu and xu register conflict.
 213 |
 214         bfextu  CMDREG2B(%a6){#6:#3},%d1        |get 2nd dest
 215         cmpb    %d0,%d1                 |cmp 1st dest with 2nd dest
 216         beqs    op0_xu                  |if equal, continue bugfix
 217         bfextu  CMDREG1B(%a6){#3:#3},%d0        |get 1st src
 218         cmpb    %d0,%d1                 |cmp 1st src with 2nd dest
 219         beq     op0_xu
 220         bne     fix_done                |if the reg checks fail, exit
 221 |
 222 | We have the opclass 0 situation.
 223 |
 224 op0:
 225         bfextu  CMDREG1B(%a6){#3:#3},%d0        |get source register no
 226         movel   #7,%d1
 227         subl    %d0,%d1
 228         clrl    %d0
 229         bsetl   %d1,%d0
 230         fmovemx %d0,ETEMP(%a6)          |load source to ETEMP
 231
 232         moveb   #0x12,%d0
 233         bfins   %d0,CMDREG1B(%a6){#0:#6}        |opclass 2, extended
 234 |
 235 |       Set ETEMP exponent bit 15 as the opposite of ete14
 236 |
 237         btst    #6,ETEMP_EX(%a6)                |check etemp exponent bit 14
 238         beq     setete15
 239         bclr    #etemp15_bit,STAG(%a6)
 240         bra     finish
 241 setete15:
 242         bset    #etemp15_bit,STAG(%a6)
 243         bra     finish
 244
 245 |
 246 | We have the case in which a conflict exists between the cu src or
 247 | dest and the dest of the xu.  We must clear the instruction in
 248 | the cu and restore the state, allowing the instruction in the
 249 | xu to complete.  Remember, the instruction in the nu
 250 | was exceptional, and was completed by the appropriate handler.
 251 | If the result of the xu instruction is not exceptional, we can
 252 | restore the instruction from the cu to the frame and continue
 253 | processing the original exception.  If the result is also
 254 | exceptional, we choose to kill the process.
 255 |
 256 |       Items saved from the stack:
 257 |
 258 |               $3c stag     - L_SCR1
 259 |               $40 cmdreg1b - L_SCR2
 260 |               $44 dtag     - L_SCR3
 261 |
 262 | The cu savepc is set to zero, and the frame is restored to the
 263 | fpu.
 264 |
 265 op0_xu:
 266         movel   STAG(%a6),L_SCR1(%a6)
 267         movel   CMDREG1B(%a6),L_SCR2(%a6)
 268         movel   DTAG(%a6),L_SCR3(%a6)
 269         andil   #0xe0000000,L_SCR3(%a6)
 270         moveb   #0,CU_SAVEPC(%a6)
 271         movel   (%a7)+,%d1              |save return address from bsr
 272         frestore (%a7)+
 273         fsave   -(%a7)
 274 |
 275 | Check if the instruction which just completed was exceptional.
 276 |
 277         cmpw    #0x4060,(%a7)
 278         beq     op0_xb
 279 |
 280 | It is necessary to isolate the result of the instruction in the
 281 | xu if it is to fp0 - fp3 and write that value to the USER_FPn
 282 | locations on the stack.  The correct destination register is in
 283 | cmdreg2b.
 284 |
 285         bfextu  CMDREG2B(%a6){#6:#3},%d0        |get dest register no
 286         cmpil   #3,%d0
 287         bgts    op0_xi
 288         beqs    op0_fp3
 289         cmpil   #1,%d0
 290         blts    op0_fp0
 291         beqs    op0_fp1
 292 op0_fp2:
 293         fmovemx %fp2-%fp2,USER_FP2(%a6)
 294         bras    op0_xi
 295 op0_fp1:
 296         fmovemx %fp1-%fp1,USER_FP1(%a6)
 297         bras    op0_xi
 298 op0_fp0:
 299         fmovemx %fp0-%fp0,USER_FP0(%a6)
 300         bras    op0_xi
 301 op0_fp3:
 302         fmovemx %fp3-%fp3,USER_FP3(%a6)
 303 |
 304 | The frame returned is idle.  We must build a busy frame to hold
 305 | the cu state information and setup etemp.
 306 |
 307 op0_xi:
 308         movel   #22,%d0         |clear 23 lwords
 309         clrl    (%a7)
 310 op0_loop:
 311         clrl    -(%a7)
 312         dbf     %d0,op0_loop
 313         movel   #0x40600000,-(%a7)
 314         movel   L_SCR1(%a6),STAG(%a6)
 315         movel   L_SCR2(%a6),CMDREG1B(%a6)
 316         movel   L_SCR3(%a6),DTAG(%a6)
 317         moveb   #0x6,CU_SAVEPC(%a6)
 318         movel   %d1,-(%a7)              |return bsr return address
 319         bfextu  CMDREG1B(%a6){#3:#3},%d0        |get source register no
 320         movel   #7,%d1
 321         subl    %d0,%d1
 322         clrl    %d0
 323         bsetl   %d1,%d0
 324         fmovemx %d0,ETEMP(%a6)          |load source to ETEMP
 325
 326         moveb   #0x12,%d0
 327         bfins   %d0,CMDREG1B(%a6){#0:#6}        |opclass 2, extended
 328 |
 329 |       Set ETEMP exponent bit 15 as the opposite of ete14
 330 |
 331         btst    #6,ETEMP_EX(%a6)                |check etemp exponent bit 14
 332         beq     op0_sete15
 333         bclr    #etemp15_bit,STAG(%a6)
 334         bra     finish
 335 op0_sete15:
 336         bset    #etemp15_bit,STAG(%a6)
 337         bra     finish
 338
 339 |
 340 | The frame returned is busy.  It is not possible to reconstruct
 341 | the code sequence to allow completion.  We will jump to
 342 | fpsp_fmt_error and allow the kernel to kill the process.
 343 |
 344 op0_xb:
 345         jmp     fpsp_fmt_error
 346
 347 |
 348 | Check for opclass 2 and single size.  If not both, exit.
 349 |
 350 op2sgl:
 351         movew   CMDREG1B(%a6),%d0
 352         andiw   #0xFC00,%d0             |strip all but opclass and size
 353         cmpiw   #0x4400,%d0             |test for opclass 2 and size=sgl
 354         bne     fix_done                |if not, it is not bug 1238
 355 |
 356 | Check for cu dest equal to nu dest or equal to xu dest, with
 357 | a cu and nu conflict taking priority an nu conflict.  If either,
 358 | go and fix the bug condition.  Otherwise, exit.
 359 |
 360         bfextu  CMDREG1B(%a6){#6:#3},%d0        |get 1st dest
 361         bfextu  CMDREG3B(%a6){#6:#3},%d1        |get 3rd dest
 362         cmpb    %d0,%d1                 |cmp 1st dest with 3rd dest
 363         beq     op2_com                 |if equal, continue bugfix
 364         bfextu  CMDREG2B(%a6){#6:#3},%d1        |get 2nd dest
 365         cmpb    %d0,%d1                 |cmp 1st dest with 2nd dest
 366         bne     fix_done                |if the reg checks fail, exit
 367 |
 368 | We have the case in which a conflict exists between the cu src or
 369 | dest and the dest of the xu.  We must clear the instruction in
 370 | the cu and restore the state, allowing the instruction in the
 371 | xu to complete.  Remember, the instruction in the nu
 372 | was exceptional, and was completed by the appropriate handler.
 373 | If the result of the xu instruction is not exceptional, we can
 374 | restore the instruction from the cu to the frame and continue
 375 | processing the original exception.  If the result is also
 376 | exceptional, we choose to kill the process.
 377 |
 378 |       Items saved from the stack:
 379 |
 380 |               $3c stag     - L_SCR1
 381 |               $40 cmdreg1b - L_SCR2
 382 |               $44 dtag     - L_SCR3
 383 |               etemp        - FP_SCR2
 384 |
 385 | The cu savepc is set to zero, and the frame is restored to the
 386 | fpu.
 387 |
 388 op2_xu:
 389         movel   STAG(%a6),L_SCR1(%a6)
 390         movel   CMDREG1B(%a6),L_SCR2(%a6)
 391         movel   DTAG(%a6),L_SCR3(%a6)
 392         andil   #0xe0000000,L_SCR3(%a6)
 393         moveb   #0,CU_SAVEPC(%a6)
 394         movel   ETEMP(%a6),FP_SCR2(%a6)
 395         movel   ETEMP_HI(%a6),FP_SCR2+4(%a6)
 396         movel   ETEMP_LO(%a6),FP_SCR2+8(%a6)
 397         movel   (%a7)+,%d1              |save return address from bsr
 398         frestore (%a7)+
 399         fsave   -(%a7)
 400 |
 401 | Check if the instruction which just completed was exceptional.
 402 |
 403         cmpw    #0x4060,(%a7)
 404         beq     op2_xb
 405 |
 406 | It is necessary to isolate the result of the instruction in the
 407 | xu if it is to fp0 - fp3 and write that value to the USER_FPn
 408 | locations on the stack.  The correct destination register is in
 409 | cmdreg2b.
 410 |
 411         bfextu  CMDREG2B(%a6){#6:#3},%d0        |get dest register no
 412         cmpil   #3,%d0
 413         bgts    op2_xi
 414         beqs    op2_fp3
 415         cmpil   #1,%d0
 416         blts    op2_fp0
 417         beqs    op2_fp1
 418 op2_fp2:
 419         fmovemx %fp2-%fp2,USER_FP2(%a6)
 420         bras    op2_xi
 421 op2_fp1:
 422         fmovemx %fp1-%fp1,USER_FP1(%a6)
 423         bras    op2_xi
 424 op2_fp0:
 425         fmovemx %fp0-%fp0,USER_FP0(%a6)
 426         bras    op2_xi
 427 op2_fp3:
 428         fmovemx %fp3-%fp3,USER_FP3(%a6)
 429 |
 430 | The frame returned is idle.  We must build a busy frame to hold
 431 | the cu state information and fix up etemp.
 432 |
 433 op2_xi:
 434         movel   #22,%d0         |clear 23 lwords
 435         clrl    (%a7)
 436 op2_loop:
 437         clrl    -(%a7)
 438         dbf     %d0,op2_loop
 439         movel   #0x40600000,-(%a7)
 440         movel   L_SCR1(%a6),STAG(%a6)
 441         movel   L_SCR2(%a6),CMDREG1B(%a6)
 442         movel   L_SCR3(%a6),DTAG(%a6)
 443         moveb   #0x6,CU_SAVEPC(%a6)
 444         movel   FP_SCR2(%a6),ETEMP(%a6)
 445         movel   FP_SCR2+4(%a6),ETEMP_HI(%a6)
 446         movel   FP_SCR2+8(%a6),ETEMP_LO(%a6)
 447         movel   %d1,-(%a7)
 448         bra     op2_com
 449
 450 |
 451 | We have the opclass 2 single source situation.
 452 |
 453 op2_com:
 454         moveb   #0x15,%d0
 455         bfins   %d0,CMDREG1B(%a6){#0:#6}        |opclass 2, double
 456
 457         cmpw    #0x407F,ETEMP_EX(%a6)   |single +max
 458         bnes    case2
 459         movew   #0x43FF,ETEMP_EX(%a6)   |to double +max
 460         bra     finish
 461 case2:
 462         cmpw    #0xC07F,ETEMP_EX(%a6)   |single -max
 463         bnes    case3
 464         movew   #0xC3FF,ETEMP_EX(%a6)   |to double -max
 465         bra     finish
 466 case3:
 467         cmpw    #0x3F80,ETEMP_EX(%a6)   |single +min
 468         bnes    case4
 469         movew   #0x3C00,ETEMP_EX(%a6)   |to double +min
 470         bra     finish
 471 case4:
 472         cmpw    #0xBF80,ETEMP_EX(%a6)   |single -min
 473         bne     fix_done
 474         movew   #0xBC00,ETEMP_EX(%a6)   |to double -min
 475         bra     finish
 476 |
 477 | The frame returned is busy.  It is not possible to reconstruct
 478 | the code sequence to allow completion.  fpsp_fmt_error causes
 479 | an fline illegal instruction to be executed.
 480 |
 481 | You should replace the jump to fpsp_fmt_error with a jump
 482 | to the entry point used to kill a process.
 483 |
 484 op2_xb:
 485         jmp     fpsp_fmt_error
 486
 487 |
 488 | Enter here if the case is not of the situations affected by
 489 | bug #1238, or if the fix is completed, and exit.
 490 |
 491 finish:
 492 fix_done:
 493         rts
 494
 495         |end