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Load %fs with the flat data segment selector while in protected mode.

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This will be used for convenient access to the BIOS variables.
This commit is contained in:
Bruce Evans 1996-03-08 05:43:46 +00:00
parent c50f3ecf5a
commit 0ae65c1a2b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=14413
1 changed files with 7 additions and 3 deletions
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10
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 1.6 1995/01/25 21:37:36 bde Exp $
* $Id: asm.S,v 1.7 1996/03/08 05:15:53 bde Exp $
*/
@ -93,12 +93,14 @@ ENTRY(real_to_prot)
xprot:
/*
* we are in USE32 mode now
* set up the protected mode segment registers : DS, SS, ES
* set up the protected mode segment registers : DS, SS, ES, FS
*/
mov $0x20, %eax
movw %ax, %ds
movw %ax, %ss
movw %ax, %es
movw $0x10, %ax /* flat segment */
movw %ax, %fs
#ifdef BDE_DEBUGGER
/* load idtr so we can debug */
@ -126,6 +128,7 @@ x16:
mov %ax, %ds
mov %ax, %ss
mov %ax, %es
mov %ax, %fs
/* clear the PE bit of CR0 */
mov %cr0, %eax
@ -143,12 +146,13 @@ xreal:
/*
* we are in real mode now
* set up the real mode segment registers : DS, SS, ES
* 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
#ifdef BDE_DEBUGGER
/* load idtr so we can debug */