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%define MAPMAGIC 0x534D4150
mmap:
mov ebx, .msg
call print_str
xor ebx, ebx ; counter for interrupt
mov di, MEMMAP
.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
cmp dword[di+16], 1
; jne .next
cmp dword[di+4], 0
jne .keep
cmp dword[di+0], 0x100000
jb .next
.keep:
mov dword[di+20], 0
add di, 24
.next:
cmp ebx, 0
jne .loop
mov dword[di+0], 0
mov dword[di+4], 0
;mov ax, di
;sub ax, MEMMAP
;xor dx, dx
;mov bx, 24
;div bx
;mov [MEMMAPCNT], ax
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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