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|

|       bugfix.sa 3.2 1/31/91

|

|

|       This file contains workarounds for bugs in the 040

|       relating to the Floating-Point Software Package (FPSP)

|

|       Fixes for bugs: 1238

|

|       Bug: 1238

|

|

|    /* The following dirty_bit clear should be left in

|     * the handler permanently to improve throughput.

|     * The dirty_bits are located at bits [23:16] in

|     * longword $08 in the busy frame $4x60.  Bit 16

|     * corresponds to FP0, bit 17 corresponds to FP1,

|     * and so on.

|     */

|    if  (E3_exception_just_serviced)   {

|         dirty_bit[cmdreg3b[9:7]] = 0;

|         }

|

|    if  (fsave_format_version != $40)  {goto NOFIX}

|

|    if !(E3_exception_just_serviced)   {goto NOFIX}

|    if  (cupc == 0000000)              {goto NOFIX}

|    if  ((cmdreg1b[15:13] != 000) &&

|         (cmdreg1b[15:10] != 010001))  {goto NOFIX}

|    if (((cmdreg1b[15:13] != 000) || ((cmdreg1b[12:10] != cmdreg2b[9:7]) &&

|                                     (cmdreg1b[12:10] != cmdreg3b[9:7]))  ) &&

|        ((cmdreg1b[ 9: 7] != cmdreg2b[9:7]) &&

|         (cmdreg1b[ 9: 7] != cmdreg3b[9:7])) )  {goto NOFIX}

|

|    /* Note: for 6d43b or 8d43b, you may want to add the following code

|     * to get better coverage.  (If you do not insert this code, the part

|     * won't lock up; it will simply get the wrong answer.)

|     * Do NOT insert this code for 10d43b or later parts.

|     *

|     *  if (fpiarcu == integer stack return address) {

|     *       cupc = 0000000;

|     *       goto NOFIX;

|     *       }

|     */

|

|    if (cmdreg1b[15:13] != 000)   {goto FIX_OPCLASS2}

|    FIX_OPCLASS0:

|    if (((cmdreg1b[12:10] == cmdreg2b[9:7]) ||

|        (cmdreg1b[ 9: 7] == cmdreg2b[9:7])) &&

|       (cmdreg1b[12:10] != cmdreg3b[9:7]) &&

|       (cmdreg1b[ 9: 7] != cmdreg3b[9:7]))  {  /* xu conflict only */

|       /* We execute the following code if there is an

|          xu conflict and NOT an nu conflict */

|

|       /* first save some values on the fsave frame */

|       stag_temp     = STAG[fsave_frame];

|       cmdreg1b_temp = CMDREG1B[fsave_frame];

|       dtag_temp     = DTAG[fsave_frame];

|       ete15_temp    = ETE15[fsave_frame];

|

|       CUPC[fsave_frame] = 0000000;

|       FRESTORE

|       FSAVE

|

|       /* If the xu instruction is exceptional, we punt.

|        * Otherwise, we would have to include OVFL/UNFL handler

|        * code here to get the correct answer.

|        */

|       if (fsave_frame_format == $4060) {goto KILL_PROCESS}

|

|       fsave_frame = /* build a long frame of all zeros */

|       fsave_frame_format = $4060;  /* label it as long frame */

|

|       /* load it with the temps we saved */

|       STAG[fsave_frame]     =  stag_temp;

|       CMDREG1B[fsave_frame] =  cmdreg1b_temp;

|       DTAG[fsave_frame]     =  dtag_temp;

|       ETE15[fsave_frame]    =  ete15_temp;

|

|       /* Make sure that the cmdreg3b dest reg is not going to

|        * be destroyed by a FMOVEM at the end of all this code.

|        * If it is, you should move the current value of the reg

|        * onto the stack so that the reg will loaded with that value.

|        */

|

|       /* All done.  Proceed with the code below */

|    }

|

|    etemp  = FP_reg_[cmdreg1b[12:10]];

|    ete15  = ~ete14;

|    cmdreg1b[15:10] = 010010;

|    clear(bug_flag_procIDxxxx);

|    FRESTORE and return;

|

|

|    FIX_OPCLASS2:

|    if ((cmdreg1b[9:7] == cmdreg2b[9:7]) &&

|       (cmdreg1b[9:7] != cmdreg3b[9:7]))  {  /* xu conflict only */

|       /* We execute the following code if there is an

|          xu conflict and NOT an nu conflict */

|

|       /* first save some values on the fsave frame */

|       stag_temp     = STAG[fsave_frame];

|       cmdreg1b_temp = CMDREG1B[fsave_frame];

|       dtag_temp     = DTAG[fsave_frame];

|       ete15_temp    = ETE15[fsave_frame];

|       etemp_temp    = ETEMP[fsave_frame];

|

|       CUPC[fsave_frame] = 0000000;

|       FRESTORE

|       FSAVE

|

|

|       /* If the xu instruction is exceptional, we punt.

|        * Otherwise, we would have to include OVFL/UNFL handler

|        * code here to get the correct answer.

|        */

|       if (fsave_frame_format == $4060) {goto KILL_PROCESS}

|

|       fsave_frame = /* build a long frame of all zeros */

|       fsave_frame_format = $4060;  /* label it as long frame */

|

|       /* load it with the temps we saved */

|       STAG[fsave_frame]     =  stag_temp;

|       CMDREG1B[fsave_frame] =  cmdreg1b_temp;

|       DTAG[fsave_frame]     =  dtag_temp;

|       ETE15[fsave_frame]    =  ete15_temp;

|       ETEMP[fsave_frame]    =  etemp_temp;

|

|       /* Make sure that the cmdreg3b dest reg is not going to

|        * be destroyed by a FMOVEM at the end of all this code.

|        * If it is, you should move the current value of the reg

|        * onto the stack so that the reg will loaded with that value.

|        */

|

|       /* All done.  Proceed with the code below */

|    }

|

|    if (etemp_exponent == min_sgl)   etemp_exponent = min_dbl;

|    if (etemp_exponent == max_sgl)   etemp_exponent = max_dbl;

|    cmdreg1b[15:10] = 010101;

|    clear(bug_flag_procIDxxxx);

|    FRESTORE and return;

|

|

|    NOFIX:

|    clear(bug_flag_procIDxxxx);

|    FRESTORE and return;

|

|               Copyright (C) Motorola, Inc. 1990

|                       All Rights Reserved

|

|       THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA

|       The copyright notice above does not evidence any

|       actual or intended publication of such source code.

|BUGFIX    idnt    2,1 | Motorola 040 Floating Point Software Package

        |section        8

        .include "fpsp.h"

        |xref   fpsp_fmt_error

        .global b1238_fix

b1238_fix:

|

| This code is entered only on completion of the handling of an

| nu-generated ovfl, unfl, or inex exception.  If the version

| number of the fsave is not $40, this handler is not necessary.

| Simply branch to fix_done and exit normally.

|

        cmpib   #VER_40,4(%a7)

        bne     fix_done

|

| Test for cu_savepc equal to zero.  If not, this is not a bug

| #1238 case.

|

        moveb   CU_SAVEPC(%a6),%d0

        andib   #0xFE,%d0

        beq     fix_done        |if zero, this is not bug #1238

|

| Test the register conflict aspect.  If opclass0, check for

| cu src equal to xu dest or equal to nu dest.  If so, go to

| op0.  Else, or if opclass2, check for cu dest equal to

| xu dest or equal to nu dest.  If so, go to tst_opcl.  Else,

| exit, it is not the bug case.

|

| Check for opclass 0.  If not, go and check for opclass 2 and sgl.

|

        movew   CMDREG1B(%a6),%d0

        andiw   #0xE000,%d0             |strip all but opclass

        bne     op2sgl                  |not opclass 0, check op2

|

| Check for cu and nu register conflict.  If one exists, this takes

| priority over a cu and xu conflict.

|

        bfextu  CMDREG1B(%a6){#3:#3},%d0        |get 1st src

        bfextu  CMDREG3B(%a6){#6:#3},%d1        |get 3rd dest

        cmpb    %d0,%d1

        beqs    op0                     |if equal, continue bugfix

|

| Check for cu dest equal to nu dest.  If so, go and fix the

| bug condition.  Otherwise, exit.

|

        bfextu  CMDREG1B(%a6){#6:#3},%d0        |get 1st dest

        cmpb    %d0,%d1                 |cmp 1st dest with 3rd dest

        beqs    op0                     |if equal, continue bugfix

|

| Check for cu and xu register conflict.

|

        bfextu  CMDREG2B(%a6){#6:#3},%d1        |get 2nd dest

        cmpb    %d0,%d1                 |cmp 1st dest with 2nd dest

        beqs    op0_xu                  |if equal, continue bugfix

        bfextu  CMDREG1B(%a6){#3:#3},%d0        |get 1st src

        cmpb    %d0,%d1                 |cmp 1st src with 2nd dest

        beq     op0_xu

        bne     fix_done                |if the reg checks fail, exit

|

| We have the opclass 0 situation.

|

op0:

        bfextu  CMDREG1B(%a6){#3:#3},%d0        |get source register no

        movel   #7,%d1

        subl    %d0,%d1

        clrl    %d0

        bsetl   %d1,%d0

        fmovemx %d0,ETEMP(%a6)          |load source to ETEMP

        moveb   #0x12,%d0

        bfins   %d0,CMDREG1B(%a6){#0:#6}        |opclass 2, extended

|

|       Set ETEMP exponent bit 15 as the opposite of ete14

|

        btst    #6,ETEMP_EX(%a6)                |check etemp exponent bit 14

        beq     setete15

        bclr    #etemp15_bit,STAG(%a6)

        bra     finish

setete15:

        bset    #etemp15_bit,STAG(%a6)

        bra     finish

|

| We have the case in which a conflict exists between the cu src or

| dest and the dest of the xu.  We must clear the instruction in

| the cu and restore the state, allowing the instruction in the

| xu to complete.  Remember, the instruction in the nu

| was exceptional, and was completed by the appropriate handler.

| If the result of the xu instruction is not exceptional, we can

| restore the instruction from the cu to the frame and continue

| processing the original exception.  If the result is also

| exceptional, we choose to kill the process.

|

|       Items saved from the stack:

|

|               $3c stag     - L_SCR1

|               $40 cmdreg1b - L_SCR2

|               $44 dtag     - L_SCR3

|

| The cu savepc is set to zero, and the frame is restored to the

| fpu.

|

op0_xu:

        movel   STAG(%a6),L_SCR1(%a6)

        movel   CMDREG1B(%a6),L_SCR2(%a6)

        movel   DTAG(%a6),L_SCR3(%a6)

        andil   #0xe0000000,L_SCR3(%a6)

        moveb   #0,CU_SAVEPC(%a6)

        movel   (%a7)+,%d1              |save return address from bsr

        frestore (%a7)+

        fsave   -(%a7)

|

| Check if the instruction which just completed was exceptional.

|

        cmpw    #0x4060,(%a7)

        beq     op0_xb

|

| It is necessary to isolate the result of the instruction in the

| xu if it is to fp0 - fp3 and write that value to the USER_FPn

| locations on the stack.  The correct destination register is in

| cmdreg2b.

|

        bfextu  CMDREG2B(%a6){#6:#3},%d0        |get dest register no

        cmpil   #3,%d0

        bgts    op0_xi

        beqs    op0_fp3

        cmpil   #1,%d0

        blts    op0_fp0

        beqs    op0_fp1

op0_fp2:

        fmovemx %fp2-%fp2,USER_FP2(%a6)

        bras    op0_xi

op0_fp1:

        fmovemx %fp1-%fp1,USER_FP1(%a6)

        bras    op0_xi

op0_fp0:

        fmovemx %fp0-%fp0,USER_FP0(%a6)

        bras    op0_xi

op0_fp3:

        fmovemx %fp3-%fp3,USER_FP3(%a6)

|

| The frame returned is idle.  We must build a busy frame to hold

| the cu state information and setup etemp.

|

op0_xi:

        movel   #22,%d0         |clear 23 lwords

        clrl    (%a7)

op0_loop:

        clrl    -(%a7)

        dbf     %d0,op0_loop

        movel   #0x40600000,-(%a7)

        movel   L_SCR1(%a6),STAG(%a6)

        movel   L_SCR2(%a6),CMDREG1B(%a6)

        movel   L_SCR3(%a6),DTAG(%a6)

        moveb   #0x6,CU_SAVEPC(%a6)

        movel   %d1,-(%a7)              |return bsr return address

        bfextu  CMDREG1B(%a6){#3:#3},%d0        |get source register no

        movel   #7,%d1

        subl    %d0,%d1

        clrl    %d0

        bsetl   %d1,%d0

        fmovemx %d0,ETEMP(%a6)          |load source to ETEMP

        moveb   #0x12,%d0

        bfins   %d0,CMDREG1B(%a6){#0:#6}        |opclass 2, extended

|

|       Set ETEMP exponent bit 15 as the opposite of ete14

|

        btst    #6,ETEMP_EX(%a6)                |check etemp exponent bit 14

        beq     op0_sete15

        bclr    #etemp15_bit,STAG(%a6)

        bra     finish

op0_sete15:

        bset    #etemp15_bit,STAG(%a6)

        bra     finish

|

| The frame returned is busy.  It is not possible to reconstruct

| the code sequence to allow completion.  We will jump to

| fpsp_fmt_error and allow the kernel to kill the process.

|

op0_xb:

        jmp     fpsp_fmt_error

|

| Check for opclass 2 and single size.  If not both, exit.

|

op2sgl:

        movew   CMDREG1B(%a6),%d0

        andiw   #0xFC00,%d0             |strip all but opclass and size

        cmpiw   #0x4400,%d0             |test for opclass 2 and size=sgl

        bne     fix_done                |if not, it is not bug 1238

|

| Check for cu dest equal to nu dest or equal to xu dest, with

| a cu and nu conflict taking priority an nu conflict.  If either,

| go and fix the bug condition.  Otherwise, exit.

|

        bfextu  CMDREG1B(%a6){#6:#3},%d0        |get 1st dest

        bfextu  CMDREG3B(%a6){#6:#3},%d1        |get 3rd dest

        cmpb    %d0,%d1                 |cmp 1st dest with 3rd dest

        beq     op2_com                 |if equal, continue bugfix

        bfextu  CMDREG2B(%a6){#6:#3},%d1        |get 2nd dest

        cmpb    %d0,%d1                 |cmp 1st dest with 2nd dest

        bne     fix_done                |if the reg checks fail, exit

|

| We have the case in which a conflict exists between the cu src or

| dest and the dest of the xu.  We must clear the instruction in

| the cu and restore the state, allowing the instruction in the

| xu to complete.  Remember, the instruction in the nu

| was exceptional, and was completed by the appropriate handler.

| If the result of the xu instruction is not exceptional, we can

| restore the instruction from the cu to the frame and continue

| processing the original exception.  If the result is also

| exceptional, we choose to kill the process.

|

|       Items saved from the stack:

|

|               $3c stag     - L_SCR1

|               $40 cmdreg1b - L_SCR2

|               $44 dtag     - L_SCR3

|               etemp        - FP_SCR2

|

| The cu savepc is set to zero, and the frame is restored to the

| fpu.

|

op2_xu:

        movel   STAG(%a6),L_SCR1(%a6)

        movel   CMDREG1B(%a6),L_SCR2(%a6)

        movel   DTAG(%a6),L_SCR3(%a6)

        andil   #0xe0000000,L_SCR3(%a6)

        moveb   #0,CU_SAVEPC(%a6)

        movel   ETEMP(%a6),FP_SCR2(%a6)

        movel   ETEMP_HI(%a6),FP_SCR2+4(%a6)

        movel   ETEMP_LO(%a6),FP_SCR2+8(%a6)

        movel   (%a7)+,%d1              |save return address from bsr

        frestore (%a7)+

        fsave   -(%a7)

|

| Check if the instruction which just completed was exceptional.

|

        cmpw    #0x4060,(%a7)

        beq     op2_xb

|

| It is necessary to isolate the result of the instruction in the

| xu if it is to fp0 - fp3 and write that value to the USER_FPn

| locations on the stack.  The correct destination register is in

| cmdreg2b.

|

        bfextu  CMDREG2B(%a6){#6:#3},%d0        |get dest register no

        cmpil   #3,%d0

        bgts    op2_xi

        beqs    op2_fp3

        cmpil   #1,%d0

        blts    op2_fp0

        beqs    op2_fp1

op2_fp2:

        fmovemx %fp2-%fp2,USER_FP2(%a6)

        bras    op2_xi

op2_fp1:

        fmovemx %fp1-%fp1,USER_FP1(%a6)

        bras    op2_xi

op2_fp0:

        fmovemx %fp0-%fp0,USER_FP0(%a6)

        bras    op2_xi

op2_fp3:

        fmovemx %fp3-%fp3,USER_FP3(%a6)

|

| The frame returned is idle.  We must build a busy frame to hold

| the cu state information and fix up etemp.

|

op2_xi:

        movel   #22,%d0         |clear 23 lwords

        clrl    (%a7)

op2_loop:

        clrl    -(%a7)

        dbf     %d0,op2_loop

        movel   #0x40600000,-(%a7)

        movel   L_SCR1(%a6),STAG(%a6)

        movel   L_SCR2(%a6),CMDREG1B(%a6)

        movel   L_SCR3(%a6),DTAG(%a6)

        moveb   #0x6,CU_SAVEPC(%a6)

        movel   FP_SCR2(%a6),ETEMP(%a6)

        movel   FP_SCR2+4(%a6),ETEMP_HI(%a6)

        movel   FP_SCR2+8(%a6),ETEMP_LO(%a6)

        movel   %d1,-(%a7)

        bra     op2_com

|

| We have the opclass 2 single source situation.

|

op2_com:

        moveb   #0x15,%d0

        bfins   %d0,CMDREG1B(%a6){#0:#6}        |opclass 2, double

        cmpw    #0x407F,ETEMP_EX(%a6)   |single +max

        bnes    case2

        movew   #0x43FF,ETEMP_EX(%a6)   |to double +max

        bra     finish

case2:

        cmpw    #0xC07F,ETEMP_EX(%a6)   |single -max

        bnes    case3

        movew   #0xC3FF,ETEMP_EX(%a6)   |to double -max

        bra     finish

case3:

        cmpw    #0x3F80,ETEMP_EX(%a6)   |single +min

        bnes    case4

        movew   #0x3C00,ETEMP_EX(%a6)   |to double +min

        bra     finish

case4:

        cmpw    #0xBF80,ETEMP_EX(%a6)   |single -min

        bne     fix_done

        movew   #0xBC00,ETEMP_EX(%a6)   |to double -min

        bra     finish

|

| The frame returned is busy.  It is not possible to reconstruct

| the code sequence to allow completion.  fpsp_fmt_error causes

| an fline illegal instruction to be executed.

|

| You should replace the jump to fpsp_fmt_error with a jump

| to the entry point used to kill a process.

|

op2_xb:

        jmp     fpsp_fmt_error

|

| Enter here if the case is not of the situations affected by

| bug #1238, or if the fix is completed, and exit.

|

finish:

fix_done:

        rts

        |end