bugfix.S
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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