71 lines
849 B
NASM
71 lines
849 B
NASM
; Parse ASCIIZ string into FCB
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; IN SI ptr to filename
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; BX ptr to FCB
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fcb_parse:
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push di
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push ax
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mov di, bx
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xor ax, ax
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stosb
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.cleanout:
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push di
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mov cx, 0x0A
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mov al, 0x20
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rep stosb
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pop di
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.base_loop:
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call .read
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cmp al, 0x2E
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je .ext_start
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cmp al, 0x20
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je .ret
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stosb
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jmp .base_loop
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.ext_start:
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mov di, bx
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add di, 9
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.ext_loop:
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call .read
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cmp al, 0x20
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je .ret
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stosb
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jmp .ext_loop
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.read:
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lodsb
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test al, al
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jz .eret
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cmp al, 0x0D
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je .eret
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ret
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.eret:
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dec si
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pop ax
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.ret:
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pop ax
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pop di
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ret
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fcb_open:
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cmp byte [bx], 0
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jne .drivedone
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mov al, default_drive
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inc al
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mov [bx], al
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.drivedone:
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push bp
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sub sp, bpb_size
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mov bp, sp
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mov dl, [bx]
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dec dl
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call bpb_load
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mov ax, [bp]
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mov cx, [bp+2]
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mov dx, [bp+4]
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mov bx, [bp+6]
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add sp, bpb_size
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pop bp
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ret
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