mirror of
https://github.com/stevenhowes/wbios.git
synced 2026-05-26 15:53:34 +01:00
Steve Howes
128 lines
2.5 KiB
Plaintext
128 lines
2.5 KiB
Plaintext
;
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; Printer BIOS
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;
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; (C)1997-2001 Pascal Dornier / PC Engines; All rights reserved.
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; This file is licensed pursuant to the COMMON PUBLIC LICENSE 0.5.
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;
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; Limitations:
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;
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; - Doesn't call INT15 function 90FE on busy wait.
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;
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; pd 991003 fixed lp_test loop
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;
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; INT 17 entry
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;
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int17: sti ;reenable interrupts
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push ds ;save registers
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push si
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push bx
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push cx
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push dx
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mov bx,ax ;save AX
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xor ax,ax ;access BIOS segment
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mov ds,ax
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cmp dx,3 ;max port ?
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jae lp_exit ;:return
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mov si,dx ;-> table index
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mov cl,[si+m_lptime] ;get time-out value
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shl si,1
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mov dx,[si+m_lpio] ;get I/O port base
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and dx,dx ;0 -> not present
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jz lp_exit
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mov al,bh ;get command code
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and al,al
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jz lp_out ;AH=0 -> output character
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dec ax
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jz lp_init ;AH=1 -> initialize
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dec ax
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jz lp_stat ;AH=2 -> get status
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lp_exit: mov al,bl ;restore AL
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pop dx ;restore registers
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pop cx
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pop bx
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pop si
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pop ds
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iret
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;
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; AH=00: output character
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;
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lp_out: mov al,bl ;output character
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out dx,al ;[DX+0]
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inc dx
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xor si,si
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lp_wait: in al,dx ;[DX+1] get status
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mov ah,al
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and al,al ;busy ?
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js lp_ok ;:no
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dec si
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jnz lp_wait
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dec cl
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jnz lp_wait
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or ah,1 ;time-out
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and ah,0f9h
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jmp short lp_out2 ;flip bits, exit
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lp_ok: inc dx
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mov al,0dh ;activate strobe
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out dx,al ;[DX+2]
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out iowait,ax
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lp_in2: mov al,0ch ;deactivate strobe
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out dx,al ;[DX+2]
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dec dx
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dec dx
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out iowait,ax
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;
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; get printer status
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;
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lp_stat: inc dx ;get status
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in al,dx ;[DX+1]
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and al,0f8h
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mov ah,al
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lp_out2: mov al,bl ;restore AL
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xor ah,048h
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jmp lp_exit
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;
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; initialize printer
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;
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lp_init: mov al,8 ;reset printer
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inc dx
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inc dx
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out dx,al ;[DX+2]
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mov cx,5000 ;wait a bit
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lp_in1: loop lp_in1
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jmp lp_in2
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;
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; test printer ports
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;
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lp_test: mov ax,1414h ;init printer time-out
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mov [m_lptime],ax
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mov [m_lptime+2],ax
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mov si,offset lp_ports
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mov di,offset m_lpio ;destination for I/O port
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lp_test0: cs: lodsw ;get I/O port to test
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and ax,ax
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jz lp_test0a ;:end of table
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xchg dx,ax ;AX -> DX port address
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call lp_test2 ;test the port
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jmp lp_test0 ;try next
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lp_test0a: mov dx,2
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lp_test1: mov ah,1 ;init port
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int 17h
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dec dx
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jns lp_test1
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ret
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lp_test2: mov ax,0aa55h ;write test pattern
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out dx,al
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out iowait,ax ;invert bus
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out iowait,ax
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in al,dx ;read back test pattern
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cmp al,55h ;correct ?
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jnz lp_test9 ;:no printer
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mov [di],dx ;store port address
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inc di
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inc di
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add byte [m_devflg+1],40h ;count printer ports in equipment flag
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lp_test9: ret
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