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Added e820 to boot.asm

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This commit is contained in:
Xnoe 2021-10-10 17:05:57 +01:00
parent 010ea7eb1d
commit 7469925ef4
Signed by: xnoe
GPG Key ID: 45AC398F44F0DAFE
1 changed files with 25 additions and 1 deletions
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26
boot.asm
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@ -43,7 +43,7 @@ bootcode:
mov word [bpSectorsPerTrack], cx mov word [bpSectorsPerTrack], cx
; Load the stage2 (32-bit) from the next sectors ; Load the stage2 (32-bit) from the next sectors
; Load it at 0x10000 ; Load it at 0x7e00
mov ax, 7e0h mov ax, 7e0h
mov es, ax mov es, ax
xor bx, bx xor bx, bx
@ -53,6 +53,30 @@ bootcode:
mov al, 9 ; Load the next 9 sectors (4.5k) mov al, 9 ; Load the next 9 sectors (4.5k)
int 13h int 13h
; We need to get the memory configuration from the BIOS now
; To do this we can use int 15h eax=e820h
; We will load the e820 data to 0x10000
mov ax, 1000h
mov es, ax
xor di, di
xor ebx, ebx
get_memory_map_loop:
mov edx, 0x534D4150
mov ecx, 24
mov eax, 0xe820
int 15h
jc mmap_finish
cmp ebx, 0
je mmap_finish
add di, 24
jmp get_memory_map_loop
mmap_finish:
; Now we should prepare to enter in to protected mode for the sole purpose of running the stage2 bootloader ; Now we should prepare to enter in to protected mode for the sole purpose of running the stage2 bootloader
; Enable the A20 line ; Enable the A20 line