diff options
| author | kato <kato@FreeBSD.org> | 1997-01-11 07:14:35 +0000 |
|---|---|---|
| committer | kato <kato@FreeBSD.org> | 1997-01-11 07:14:35 +0000 |
| commit | 28348225e5d0c64129b52fd69842b86a2bed19ef (patch) | |
| tree | aff35f0414df71b75ebd877b3a1d21dd0177f725 /sys | |
| parent | cff4731777d863a3d72ff8c5a90a9911f41ccfaf (diff) | |
| download | FreeBSD-src-28348225e5d0c64129b52fd69842b86a2bed19ef.zip FreeBSD-src-28348225e5d0c64129b52fd69842b86a2bed19ef.tar.gz | |
Change initialize routine of Cyrix 5x86 CPU.
- Turn off BTB (Branch Target Buffer) because the BTB makes system
unstable on some machines. The BTB feature can be enabled if
"options BTB_EN" is added in kernel a configuration file.
- Change comment.
- Reorder `orb XX,%al's.
- Reset NMI F/F (mask NMI) before setting registers, and set it after
setting them. Normally, this change has no effect.
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/pc98/i386/locore.s | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/sys/pc98/i386/locore.s b/sys/pc98/i386/locore.s index d098f5a..4afc6e4 100644 --- a/sys/pc98/i386/locore.s +++ b/sys/pc98/i386/locore.s @@ -34,7 +34,7 @@ * SUCH DAMAGE. * * from: @(#)locore.s 7.3 (Berkeley) 5/13/91 - * $Id: locore.s,v 1.6 1996/11/09 00:39:35 asami Exp $ + * $Id: locore.s,v 1.7 1996/12/04 04:20:22 asami Exp $ * * originally from: locore.s, by William F. Jolitz * @@ -407,6 +407,8 @@ begin: #ifdef CYRIX_5X86 /* CYRIX 5x86 CPU */ cli + + outb %al,$0x50 # Reset NMI F/F mov %cr0,%eax orl $0x40000000,%eax # disable cache movl %eax,%cr0 @@ -419,7 +421,7 @@ begin: movb $0x0c1,%al # CCR1 outb %al,$0x22 - movb $0x00,%al + movb $0x00,%al # No SMM support outb %al,$0x23 movb $0x0c2,%al # CCR2 outb %al,$0x22 @@ -428,7 +430,7 @@ begin: #else movb $0x02,%al # USE_WBAK #endif - outb %al,$0x23 # Interface Pins + outb %al,$0x23 movb $0xc3,%al # CCR3 outb %al,$0x22 # movb $0x10,%al # MAPEN0 (to access CCR4) @@ -447,15 +449,18 @@ begin: outb %al,$0x23 movb $0x020,%al # PCR0 outb %al,$0x22 - movb $0x02, %al # BTB_EN -#ifndef DISALBE_5X86_LSSER - orb $0x80, %al # LSSER -#endif + xorb %al, %al #ifdef RSTK_EN - orb $0x01, %al + orb $0x01, %al # Return Stack Enable +#endif +#ifdef BTB_EN + orb $0x02, %al # Branch Target Buffer enable #endif #ifdef LOOP_EN - orb $0x04, %al + orb $0x04, %al # Loop Enable +#endif +#ifndef DISALBE_5X86_LSSER + orb $0x80, %al # Reorder #endif outb %al,$0x23 movb $0x0c3,%al # CCR3 @@ -471,6 +476,7 @@ begin: orl $0x020000000,%ebx # write back mode movl %ebx,%cr0 # go! + outb %al,$0x52 # Set NMI F/F sti #endif /* CYRIX_5X86 */ #endif /* PC98 */ |
