47 lines
1.2 KiB
PHP
47 lines
1.2 KiB
PHP
fix_chs:
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mov ah, 0x08
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int 0x13
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jc chs_end ; skip if function does not exist
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inc dh
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mov [cs:fdc.nos], dh
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mov ax, cx
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and ax, 0x003F
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mov [cs:fdc.spt], ax ; no adjustment because sectors are 1-indexed
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mov ax, cx
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xchg al, ah
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mov cl,6
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shr ah,cl
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inc ax ; convert from maximum number (0-based) to total number (1-based) of cylinders
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mul word [cs:fdc.nos] ; number of tracks = number of cylinders * heads
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mul word [cs:fdc.spt] ; number of sectors = number of tracks * sectors per track
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mov [cs:fdc.ts], ax
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jmp chs_end
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; Load a single sector into memory
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; Does not return on error
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; in dx:ax sector number (will be trashed)
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; es:bx buffer
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load_sector:
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push cx
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div word [cs:fdc.spt] ; ax:temp = (lba / spt)
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inc dx ; dx:sector = (lba % spt) + 1
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mov cl, dl ; sector number
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xor dx, dx
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div word [cs:fdc.nos] ; ax:cylinder = (tmp / heads)
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; dx:head = (tmp % heads)
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mov ch, al ; cylinder number
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mov dh, dl ; head number
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mov dl, [cs:fdc.drv] ; driver number
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mov ax, 0x0201 ; ah=0x02 al=0x01
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int 0x13
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jc disk_error
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; return
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pop cx
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ret
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disk_error:
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xchg al, ah
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call error
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db "DISK ERROR", 0
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chs_end: |