mirror of
https://gitlab.com/qemu-project/qboot.git
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139 lines
2.1 KiB
ArmAsm
139 lines
2.1 KiB
ArmAsm
/*
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* Our pretty trivial BIOS emulation
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*/
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#include "assembly.h"
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#include "processor-flags.h"
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.org 0
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.code16gcc
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/*
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* handy BIOS macros
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*/
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/* If you change these macros, remember to update 'struct biosregs' */
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.macro SAVE_BIOSREGS
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pushl %fs
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pushl %es
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pushl %ds
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pushl %edi
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pushl %esi
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pushl %ebp
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pushl %esp
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pushl %edx
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pushl %ecx
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pushl %ebx
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pushl %eax
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.endm
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.macro RESTORE_BIOSREGS
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popl %eax
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popl %ebx
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popl %ecx
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popl %edx
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popl %esp
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popl %ebp
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popl %esi
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popl %edi
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popl %ds
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popl %es
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popl %fs
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.endm
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ENTRY(bios_irq)
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pushw %ax
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mov $0x20, %al
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out %al, $0x20
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popw %ax
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IRET
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ENTRY_END(bios_irq)
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/*
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* fake interrupt handler, nothing can be faster ever
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*/
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ENTRY(bios_intfake)
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/*
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* Set CF to indicate failure. We don't want callers to think that the
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* interrupt handler succeeded and then treat the return values in
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* registers as valid data.
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*/
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orb $X86_EFLAGS_CF, 0x4(%esp)
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IRET
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ENTRY_END(bios_intfake)
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/*
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* int 10 - video - service
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*/
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ENTRY(bios_int10)
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andb $~X86_EFLAGS_CF, 0x4(%esp)
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SAVE_BIOSREGS
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movl %esp, %eax
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/* this is way easier than doing it in assembly */
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/* just push all the regs and jump to a C handler */
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call int10_handler
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RESTORE_BIOSREGS
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IRET
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ENTRY_END(bios_int10)
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ENTRY(bios_int15)
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andb $~X86_EFLAGS_CF, 0x4(%esp)
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SAVE_BIOSREGS
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movl %esp, %eax
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call int15_handler
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RESTORE_BIOSREGS
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IRET
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ENTRY_END(bios_int15)
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.code32
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ENTRY(pcibios_entry)
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clc
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pushfl
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SAVE_BIOSREGS
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movl %esp, %eax
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call pcibios_handler
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RESTORE_BIOSREGS
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popfl
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lretl
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ENTRY_END(pcibios_entry)
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ENTRY(bios32_entry)
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pushfl
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testl %ebx, %ebx /* BIOS32 service directory? */
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jnz 2f
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cmp $0x49435024, %eax /* "$PCI"? */
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movb $0x80, %al /* service not present */
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jne 1f
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xorl %ebx, %ebx /* fill in base/length/entry */
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movl $(1 << 20), %ecx
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movl $pcibios_entry, %edx
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movb $0x00, %al /* service present */
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1:
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popfl
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lretl
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2:
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movb $0x81, %al /* unimplemented function */
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popfl
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lretl
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ENTRY_END(bios32_entry)
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ENTRY(pic_base)
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call 1f
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2:
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ret
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1:
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popl %eax
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pushl %eax
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subl $2b, %eax
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ret /* return to 2b */
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ENTRY_END(pic_base)
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