Jeremy Soller
35 lines
777 B
NASM
35 lines
777 B
NASM
struc mbr_partition_rec
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.sys: resb 1
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.chs_start: resb 3
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.ty: resb 1
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.chs_end: resb 3
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.lba_start: resd 1
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.sector_count: resd 1
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endstruc
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; Find a partition to load RedoxFS from.
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; The partition has to be one of the primary MBR partitions.
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; OUT
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; eax - start_lba
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; CLOBBER
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; ebx
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find_redoxfs_partition:
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xor ebx, ebx
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.loop:
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mov al, byte [partitions + mbr_partition_rec + mbr_partition_rec.ty]
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cmp al, 0x83
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je .found
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add ebx, 1
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cmp ebx, 4
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jb .loop
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jmp .notfound
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.found:
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mov eax, [partitions + mbr_partition_rec + mbr_partition_rec.lba_start]
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ret
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.notfound:
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mov si, .no_partition_found_msg
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call print
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mov eax, (filesystem - boot) / 512
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ret
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.no_partition_found_msg: db "No MBR partition with type 0x83 found", 0xA, 0xD, 0
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