de.asm

很好的键盘驱动代码

pagenum    equ  20h
bufferline equ  8h
buffercol  equ  0ah
buffercol2 equ  3eh
inputline  equ  6h
inputcol   equ  06h
KEY_UP     equ  4800h
KEY_DOWN   equ  5000h
KEY_LEFT   equ  4b00h
KEY_RIGHT  equ  4d00h
KEY_PageUp equ  4900h
KEY_PageDown equ 5100h

code segment
assume cs:code,ds:code
start:  jmp go
buffer  db      100h dup(?)
        db      100h dup(?)
state   db      0h
regch   db      0
regcl   db      1
regdh   db      0
regdl   db      0
regposition     db      0h
bufferposition  db      00h
lastposition    dw      ?
lastattrib      db      1fh
hextable db     '0','1','2','3','4','5','6','7'
         db     '8','9','A','B','C','D','E','F'
caption db      'CH:   CL:   DH:   DL:   ',0


ASCTOHEX        proc    near
        push    si
        push    cx
        push    bx
        push    ax
        xchg    ah,al
        cmp     ah,'a'
        jc      asctohex_skip
        sub     ah,20h
asctohex_skip:
        lea     si,hextable
        mov     cx,10h
asctohex_next:
        lodsb
        cmp     ah,al
        jz      asctohex_bingo
        loop    asctohex_next
        stc
        pop     ax
        jmp     asctohex_over
asctohex_bingo:
        mov     al,10h
        sub     al,cl
        clc
        pop     bx
        xchg    ah,bh
asctohex_over:
        pop     bx
        pop     cx
        pop     si
        ret
ASCTOHEX        endp


LOCATECURSOR    proc    near
        push    ax
        push    bx
        push    cx
        push    dx
        mov     dx,lastposition
        call    setcursor
        mov     ah,8
        xor     bh,bh
        int     10h
        mov     bl,lastattrib
        mov     cx,1
        call    dispcharx

        mov     al,state
        test    al,80h
        jz      locatecursor_inbuffer
        mov     dx,inputline*100h+inputcol
        mov     al,regposition
        shr     al,1
        mov     bl,6
        mul     bl
        add     dl,al
        mov     al,regposition
        test    al,1h
        jz      locatecursor_skip_2
        inc     dl
locatecursor_skip_2:
        call    setcursor
        jmp     locatecursor_over

locatecursor_inbuffer:
        mov     dh,bufferline
        test    al,40h
        jz      locatecursor_hex
        mov     dl,buffercol2
        mov     bx,101h
        jmp     locatecursor_skip_1
locatecursor_hex:
        mov     dl,buffercol
        mov     bx,302h
locatecursor_skip_1:
        mov     al,bufferposition
        mov     cl,4
        shr     al,cl
        add     dh,al
        mov     al,bufferposition
        and     al,0fh
        mul     bh
        add     dl,al
        mov     al,bufferposition
        test    al,08h
        jz      locatecursor_skip_4
        add     dl,bl
locatecursor_skip_4:
        mov     al,state
        test    al,1
        jz      locatecursor_skip_3
        test    al,40h
        jnz     locatecursor_skip_3
        inc     dl
locatecursor_skip_3:
        call    setcursor
locatecursor_over:
        mov     lastposition,dx
        mov     ah,8
        xor     bh,bh
        int     10h
        mov     lastattrib,ah
        mov     bl,1fh
        mov     cx,1 
        call    dispcharx
        pop     dx
        pop     cx
        pop     bx
        pop     ax
        ret
LOCATECURSOR    endp


SETCURSOR  proc near
        push    ax
        push    bx
        mov     ah,2
        xor     bh,bh
        int     10h
        pop     bx
        pop     ax
        ret
SETCURSOR endp


GETCURSOR  proc near
        push    ax
        push    bx
        mov     ah,3
        xor     bh,bh
        int     10h
        pop     bx
        pop     ax
        ret
GETCURSOR endp


DISPCHAR  proc near
        push    ax
        push    bx
        push    cx
        mov     ah,9
        xor     bh,bh
        int     10h
        pop     cx
        pop     bx
        pop     ax
        ret
DISPCHAR  endp


DISPCHARX proc near     ;  display  chars in the appointed position 
        push    ax      ;   and the appointed attribute.             
        push    bx
        push    cx
        push    dx
        call    setcursor
        call    dispchar
        pop     dx
        pop     cx
        pop     bx
        pop     ax
        ret
DISPCHARX endp 


SHOWBAR proc near
        push    ax
        push    bx
        push    cx
        push    dx
        push    si

        mov     bl,1fh          ;  attribute.

        mov     al,' '          ;  set the backcolor.
        mov     cx,80*25
        mov     dx,0
        call    dispcharx

        mov     al,201          ;  display '