/* * Copyright (C) 1994 by HOSOKAWA, Tatsumi * * 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 1.7 1996/07/10 15:09:48 nate Exp $ */ #include "apm.h" #if NAPM > 0 #define ASSEMBLER #include "assym.s" /* system definitions */ #include /* miscellaneous asm macros */ #include #include #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 ) */ /* * 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