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%define MAPMAGIC 0x534D4150
mmap:
mov ebx, .msg
call print_str
xor ebx, ebx ; counter for interrupt
mov di, MEMMAP
xor esi, esi ; number of regions
.loop:
; issue an INT 0x15, EAX = 0xE820 interrupt
mov eax, 0xE820
mov ecx, 24
mov edx, MAPMAGIC
int 0x15
cmp eax, MAPMAGIC ; detect failure
jne .fail
inc esi
add di, 24
cmp ebx, 0
jne .loop
mov dword[di+0], 0
mov dword[di+4], 0
mov dword[bootinfo.mmap_len+0], esi
mov dword[bootinfo.mmap_len+4], 0
mov dword[bootinfo.mmap_ptr+0], MEMMAP
mov dword[bootinfo.mmap_ptr+4], 0
ret
.fail:
mov ebx, .fail_msg
call print_str
jmp $
.msg: db "getting extended memory map", 10, 13, 0
.fail_msg: db "memory map failure", 10, 13, 0
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