21 lines
457 B
NASM
21 lines
457 B
NASM
section .bss
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; default drive if field in FCB = 0
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defdrv: resb 1
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section .text
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; Functions here generally expect the FCB to be at ES:BX
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; Helper function: read the drive number from FCB,
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; apply default if necessary,
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; and make it current I/O drive
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setdrv: mov dl, [es:bx] ; A=1
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test dl, dl
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jnz .nofix
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mov dl, [defdrv] ; A=0
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inc dl
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mov [es:bx], dl ; A=1
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; now set as current i/o drive
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.nofix: dec dl ; A=0 for dsksel
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jmp logdrv
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