patch-1.3.94 linux/arch/m68k/fpsp040/bugfix.S

• Lines: 497
• Date: Sat Feb 24 22:58:42 1996
• Orig file: v1.3.93/linux/arch/m68k/fpsp040/bugfix.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/fpsp040/bugfix.S linux/arch/m68k/fpsp040/bugfix.S
@@ -0,0 +1,496 @@
+|
+|	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