| /* |
| * 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. |
| */ |
| orb $X86_EFLAGS_CF, 0x4(%esp) |
| |
| IRET |
| ENTRY_END(bios_intfake) |
| |
| /* |
| * int 10 - video - service |
| */ |
| ENTRY(bios_int10) |
| andb $~X86_EFLAGS_CF, 0x4(%esp) |
| 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 |
| |
| IRET |
| ENTRY_END(bios_int10) |
| |
| ENTRY(bios_int15) |
| andb $~X86_EFLAGS_CF, 0x4(%esp) |
| SAVE_BIOSREGS |
| |
| movl %esp, %eax |
| call int15_handler |
| |
| RESTORE_BIOSREGS |
| |
| IRET |
| ENTRY_END(bios_int15) |
| |
| .code32 |
| ENTRY(pcibios_entry) |
| clc |
| pushfl |
| SAVE_BIOSREGS |
| |
| movl %esp, %eax |
| call pcibios_handler |
| |
| RESTORE_BIOSREGS |
| popfl |
| lretl |
| ENTRY_END(pcibios_entry) |
| |
| ENTRY(bios32_entry) |
| pushfl |
| testl %ebx, %ebx /* BIOS32 service directory? */ |
| jnz 2f |
| cmp $0x49435024, %eax /* "$PCI"? */ |
| movb $0x80, %al /* service not present */ |
| jne 1f |
| xorl %ebx, %ebx /* fill in base/length/entry */ |
| movl $(1 << 20), %ecx |
| movl $pcibios_entry, %edx |
| movb $0x00, %al /* service present */ |
| 1: |
| popfl |
| lretl |
| 2: |
| movb $0x81, %al /* unimplemented function */ |
| popfl |
| lretl |
| ENTRY_END(bios32_entry) |
| |
| ENTRY(pic_base) |
| call 1f |
| 2: |
| ret |
| 1: |
| popl %eax |
| pushl %eax |
| subl $2b, %eax |
| ret /* return to 2b */ |
| ENTRY_END(pic_base) |
