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Saved 14 bytes by avoiding gas braindamage and 8 bytes by better

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instruction selection, for a total of 16 bytes after padding.  Whee.
This commit is contained in:
Bruce Evans 1996-03-08 07:27:52 +00:00
parent 6add522f93
commit bb859b2bb8
1 changed files with 22 additions and 23 deletions
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45
sys/i386/boot/biosboot/asm.S
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@ -24,7 +24,7 @@
* the rights to redistribute these changes.
*
* from: Mach, Revision 2.2 92/04/04 11:34:13 rpd
* $Id: asm.S,v 1.7 1996/03/08 05:15:53 bde Exp $
* $Id: asm.S,v 1.8 1996/03/08 05:43:46 bde Exp $
*/
@ -89,18 +89,18 @@ ENTRY(real_to_prot)
*/
data32
ljmp $0x18, $xprot
xprot:
/*
* we are in USE32 mode now
* set up the protected mode segment registers : DS, SS, ES, FS
*/
mov $0x20, %eax
movw %ax, %ds
movw %ax, %ss
movw %ax, %es
movw $0x20, %ax /* data segment */
mov %ax, %ds /* gas would waste a prefix byte for movw */
mov %ax, %ss
mov %ax, %es
movw $0x10, %ax /* flat segment */
movw %ax, %fs
mov %ax, %fs
#ifdef BDE_DEBUGGER
/* load idtr so we can debug */
@ -148,11 +148,11 @@ xreal:
* we are in real mode now
* set up the real mode segment registers : DS, SS, ES, FS
*/
movw %cs, %ax
movw %ax, %ds
movw %ax, %ss
movw %ax, %es
movw %ax, %fs
mov %cs, %ax
mov %ax, %ds
mov %ax, %ss
mov %ax, %es
mov %ax, %fs
#ifdef BDE_DEBUGGER
/* load idtr so we can debug */
@ -179,8 +179,8 @@ ENTRY(startprog)
movl %esp, %eax /* Use eax as the old stack pointer */
/* convert the current stack to a 32 bit flat model */
mov $0x10, %ebx
movw %bx, %ss
movw $0x10, %bx
mov %bx, %ss
addl $(BOOTSEG<<4),%esp
/* copy the arguments from the old stack to the new stack */
@ -199,9 +199,9 @@ ENTRY(startprog)
pushl 0x08(%eax) /* kernel entry address */
/* convert over the other data segs */
mov $0x10, %ebx
movw %bx, %ds
movw %bx, %es
movw $0x10, %bx
mov %bx, %ds
mov %bx, %es
/* convert the PC (and code seg) */
lret
@ -226,12 +226,12 @@ ENTRY(pbzero)
cld
/* set %es to point at the flat segment */
mov $0x10, %eax
movw %ax, %es
movw $0x10, %ax
mov %ax, %es
mov 0x8(%ebp), %edi /* destination */
mov 0xc(%ebp), %ecx /* count */
mov $0x0, %eax /* value */
xorl %eax, %eax /* value 0 */
rep
stosb
@ -259,8 +259,8 @@ ENTRY(pcpy)
cld
/* set %es to point at the flat segment */
mov $0x10, %eax
movw %ax, %es
movw $0x10, %ax
mov %ax, %es
mov 0x8(%ebp), %esi /* source */
mov 0xc(%ebp), %edi /* destination */
@ -276,4 +276,3 @@ ENTRY(pcpy)
pop %ebp
ret