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/*
* Our pretty trivial BIOS emulation
*/
#include "assembly.h"
#include "processor-flags.h"
.org 0
.code16gcc
/*
* handy BIOS macros
*/
/* If you change these macros, remember to update 'struct biosregs' */
.macro SAVE_BIOSREGS
pushl %fs
pushl %es
pushl %ds
pushl %edi
pushl %esi
pushl %ebp
pushl %esp
pushl %edx
pushl %ecx
pushl %ebx
pushl %eax
.endm
.macro RESTORE_BIOSREGS
popl %eax
popl %ebx
popl %ecx
popl %edx
popl %esp
popl %ebp
popl %esi
popl %edi
popl %ds
popl %es
popl %fs
.endm
ENTRY(bios_irq)
pushw %ax
mov $0x20, %al
out %al, $0x20
popw %ax
IRET
ENTRY_END(bios_irq)
/*
* fake interrupt handler, nothing can be faster ever
*/
ENTRY(bios_intfake)
/*
* Set CF to indicate failure. We don't want callers to think that the
* interrupt handler succeeded and then treat the return values in
* registers as valid data.
*/
orl $X86_EFLAGS_CF, 0x4(%esp)
IRET
ENTRY_END(bios_intfake)
/*
* int 10 - video - service
*/
ENTRY(bios_int10)
SAVE_BIOSREGS
movl %esp, %eax
/* this is way easier than doing it in assembly */
/* just push all the regs and jump to a C handler */
call int10_handler
RESTORE_BIOSREGS
/* Clear CF to indicate success. */
andl $~X86_EFLAGS_CF, 0x4(%esp)
IRET
ENTRY_END(bios_int10)
ENTRY(bios_int15)
SAVE_BIOSREGS
movl %esp, %eax
call int15_handler
RESTORE_BIOSREGS
IRET
ENTRY_END(bios_int15)
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