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Shorten the Cyrix handling code a little.

This commit is contained in:
mycroft 1994-11-14 23:35:48 +00:00
parent add2031dcf
commit e91e570cfd
1 changed files with 19 additions and 17 deletions
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36
sys/arch/i386/i386/locore.s
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@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.97 1994/11/07 05:32:50 mycroft Exp $ */
/* $NetBSD: locore.s,v 1.98 1994/11/14 23:35:48 mycroft Exp $ */
#undef DIAGNOSTIC
#define DIAGNOSTIC
@ -236,23 +236,24 @@ try486: /* Try to toggle identification flag; does not exist on early 486s. */
jnz try586
is486: movl $CPU_486,_cpu-KERNBASE
/* check for Cyrix 486DLC -- based on check routine */
/* documented in "Cx486SLC/e SMM Programmer's Guide" */
xorw %dx,%dx
cmpw %dx,%dx # set flags to known state
pushfw
popw %cx # store flags in ecx
movw $0xffff,%ax
movw $0x0004,%bx
divw %bx
pushfw
popw %ax
andw $0x08d5,%ax # mask off important bits
andw $0x08d5,%cx
cmpw %ax,%cx
jnz 2f # if flags changed, Intel chip
/*
* Check for Cyrix CPU by seeing if the flags change during a divide.
* This is documented in the Cx486SLC/e SMM Programmer's Guide.
*/
xorl %edx,%edx
cmpl %edx,%edx # set flags to known state
pushfl
popl %ecx # store flags in ecx
movl $-1,%eax
movl $4,%ebx
divl %ebx # do a long division
pushfl
popl %eax
xorl %ecx,%eax # are the flags different?
testl $0x8d5,%eax # only check C|PF|AF|Z|N|V
jne 2f # yes; must not be Cyrix CPU
movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix
movl $CPU_486DLC,_cpu-KERNBASE # set CPU type
movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string
movw $0x0078,_cpu_vendor-KERNBASE+4
@ -1527,6 +1528,7 @@ ENTRY(idle)
testl %ecx,%ecx
jnz sw1
sti
hlt
jmp _idle
#ifdef DIAGNOSTIC