freebsd-src/sys/i386/apm/apm_setup.s
Nate Williams 6774cdb846 Whee. Fix two bugs which ended up cancelling each other out.
apm_setup.s was storing apm_cs16_base and apm_cs32_base addresses in
each others slots, and apm.c was reversing the result so the bugs
cancelled out, but the code looked wrong.

No functional differences unfortunately.

Submitted by:	dave edmondson <davided@sco.com>
1996-07-10 15:09:48 +00:00

180 lines
4.0 KiB
ArmAsm

/*
* LP (Laptop Package)
*
* Copyright (C) 1994 by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>
*
* This software may be used, modified, copied, distributed, and sold,
* in both source and binary form provided that the above copyright and
* these terms are retained. Under no circumstances is the author
* responsible for the proper functioning of this software, nor does
* the author assume any responsibility for damages incurred with its
* use.
*
* Sep., 1994 Implemented on FreeBSD 1.1.5.1R (Toshiba AVS001WD)
*
* $Id: apm_setup.s,v 1.6 1996/03/11 06:48:48 nate Exp $
*/
#include "apm.h"
#if NAPM > 0
#define ASSEMBLER
#include "assym.s" /* system definitions */
#include <machine/asmacros.h> /* miscellaneous asm macros */
#include <machine/apm_bios.h>
#include <machine/apm_segments.h>
#define PADDR(addr) addr-KERNBASE
.file "apm_setup.s"
.data
_apm_init_image:
.globl _apm_init_image
1:
#include "i386/apm/apm_init/apm_init.inc"
2:
_apm_init_image_size:
.globl _apm_init_image_size
.long 2b - 1b
_apm_version:
.globl _apm_version
.long 0
_apm_cs_entry:
.globl _apm_cs_entry
.long 0
_apm_cs16_base:
.globl _apm_cs16_base
.word 0
_apm_cs32_base:
.globl _apm_cs32_base
.word 0
_apm_ds_base:
.globl _apm_ds_base
.word 0
_apm_cs_limit:
.globl _apm_cs_limit
.word 0
_apm_ds_limit:
.globl _apm_ds_limit
.word 0
_apm_flags:
.globl _apm_flags
.word 0
.globl _apm_current_gdt_pdesc /* current GDT pseudo desc. */
_apm_current_gdt_pdesc:
.word 0, 0, 0
.globl _bootstrap_gdt
_bootstrap_gdt:
.space SIZEOF_GDT*BOOTSTRAP_GDT_NUM
.text
_apm_setup:
.globl _apm_setup
/*
* Setup APM BIOS:
*
* APM BIOS initialization should be done from real mode or V86 mode.
*
* (by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>)
*/
/*
* Don't trust the value of %fs and %gs (some AT-compatible BIOS
* implementations leave junk values in these segment registers
* on bootstrap)
*/
xorl %eax, %eax /* null selector */
movw %ax, %fs
movw %ax, %gs
/*
* Copy APM initializer under 1MB boundary:
*
* APM initializer program must switch the CPU to real mode.
* But FreeBSD kernel runs above 1MB boundary. So we must
* copy the initializer code to conventional memory.
*/
movl PADDR(_apm_init_image_size), %ecx /* size */
lea PADDR(_apm_init_image), %esi /* source */
movl $ APM_OURADDR, %edi /* destination */
cld
rep
movsb
/* get GDT base */
sgdt PADDR(_apm_current_gdt_pdesc)
/* copy GDT to _bootstrap_gdt */
xorl %ecx, %ecx
movw PADDR(_apm_current_gdt_pdesc), %cx
movl PADDR(_apm_current_gdt_pdesc + 2), %esi
lea PADDR(_bootstrap_gdt), %edi
cld
rep
movsb
/* setup GDT pseudo descriptor */
movw $(SIZEOF_GDT*BOOTSTRAP_GDT_NUM), %ax
movw %ax, PADDR(_apm_current_gdt_pdesc)
leal PADDR(_bootstrap_gdt), %eax
movl %eax, PADDR(_apm_current_gdt_pdesc + 2)
/* load new GDTR */
lgdt PADDR(_apm_current_gdt_pdesc)
/* setup GDT for APM initializer */
lea PADDR(_bootstrap_gdt), %ecx
movl $(APM_OURADDR), %eax /* use %ax for 15..0 */
movl %eax, %ebx
shrl $16, %ebx /* use %bl for 23..16 */
/* use %bh for 31..24 */
#define APM_SETUP_GDT(index, attrib) \
movl $(index), %si ; \
lea 0(%ecx,%esi,8), %edx ; \
movw $0xffff, (%edx) ; \
movw %ax, 2(%edx) ; \
movb %bl, 4(%edx) ; \
movw $(attrib), 5(%edx) ; \
movb %bh, 7(%edx)
APM_SETUP_GDT(APM_INIT_CS_INDEX , CS32_ATTRIB)
APM_SETUP_GDT(APM_INIT_DS_INDEX , DS32_ATTRIB)
APM_SETUP_GDT(APM_INIT_CS16_INDEX, CS16_ATTRIB)
APM_SETUP_GDT(APM_INIT_DS16_INDEX, DS16_ATTRIB)
/*
* Call the initializer:
*
* direct intersegment call to conventional memory code
*/
.byte 0x9a /* actually, lcall $APM_INIT_CS_SEL, $0 */
.long 0
.word APM_INIT_CS_SEL
movl %eax, PADDR(_apm_version)
movl %ebx, PADDR(_apm_cs_entry)
movw %cx, PADDR(_apm_cs16_base)
shrl $16, %ecx
movw %cx, PADDR(_apm_cs32_base)
movw %dx, PADDR(_apm_ds_base)
movw %si, PADDR(_apm_cs_limit)
shrl $16, %esi
movw %si, PADDR(_apm_ds_limit)
movw %di, PADDR(_apm_flags)
ret
#endif NAPM > 0