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Merge pull request #61 from vmttmv/main

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stage1: fix load addresses for stage2/kernel
This commit is contained in:
Gregory Kenneth Bowne
2025-10-25 14:53:23 -07:00
committed by GitHub
parent 6267863939 c22f6b6f14
commit 9cde2e708d
1 changed files with 4 additions and 5 deletions
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9
bootloader/boot.asm
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@@ -23,18 +23,17 @@ start:
; Load second-stage bootloader (boot1.asm) to 0x7E00
mov ax, 1 ; LBA of boot1.asm (starts at sector 1)
call lba_to_chs
mov si, 0x7E00
mov al, 4 ; Number of sectors to read
mov bx, 0x7E00 ; Destination address offset ES = 0 (0x0000:0x7E00)
call read_chs
; Load kernel to 0x100000 (1 MB)
mov si, 0x0000 ; Destination offset
mov ax, 0x1000 ; ES = 0x1000 (0x1000:0x0000 = 1 MB)
mov es, ax
xor bx, bx
mov ax, 0xffff
mov es, ax ; Set ES for destination address (0xffff << 4 == 0xffff0)
mov ax, 5 ; LBA of kernel start (boot1 is 4 sectors: LBA 1–4 → kernel at LBA 5)
call lba_to_chs
mov al, 16 ; Number of sectors for kernel
mov bx, 0x10 ; Destination address offset (0xffff:0x10 = 0xffff << 4 + 0x10 = 0x100000)
call read_chs
jc disk_error