limine/common/protos/multiboot_reloc.asm_x86
2022-06-29 12:41:42 +02:00

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section .data
bits 32
global multiboot_reloc_stub
multiboot_reloc_stub:
jmp .code
times 4-($-multiboot_reloc_stub) db 0
; EBX = self
; ESI = magic value
; EDI = protocol info
; ECX = entry point
; EAX = ranges
; EDX = ranges count
.code:
mov esp, ebx
add esp, .mini_stack_top - multiboot_reloc_stub
push edi
push esi
push ecx
.ranges_loop:
test edx, edx ; Loop until we're done
jz .ranges_loop_out
mov esi, [eax] ; ESI = range.elsewhere
mov edi, [eax+8] ; EDI = range.target
mov ecx, [eax+16] ; ECX = range.length
rep movsb ; Copy range to target location
add eax, 24 ; Move to the next range
dec edx
jmp .ranges_loop
.ranges_loop_out:
; We're done relocating!
pop ecx
pop esi
pop edi
push ecx
mov eax, esi ; EAX = magic value
mov ebx, edi ; EBX = protocol info
xor ecx, ecx
xor edx, edx
xor esi, esi
xor edi, edi
xor ebp, ebp
ret
align 16
.mini_stack:
times 3 dq 0
.mini_stack_top:
global multiboot_reloc_stub_end
multiboot_reloc_stub_end: