关于键盘中断

[GhostAdz]

我把中断向量表里的int 9h键盘中断的地址换用我自己的new_int代替
使敲击键盘时执行我的程序，下面是我用来代替原来int 9h的程序，
一旦敲击键盘便输出一个大写A，程序成功，可是我不知道为什么要测试键盘缓冲区是否为空
不测试的话就不能正确的输出A了!!!
new_int proc
sti
push ax
pushf

call dword ptr cs:save ;原来的int 9的地址

mov ah,1 ;为何要测试键盘缓冲区是否为空？
int 16h
jz exit ;如果空就跳出

cmp al,73h
jnz exit

mov ax,0e41h
int 10h

mov ah,0 ;清空键盘缓冲区
int 16h
exit:
pop ax
iret
new_int endp

[GhostAdz]

哪为高手谁能回答我啊

[紫郢剑侠]

键盘缓冲区是先进先出的队列.

我喜欢在DOS下用QE.EXE来阅读文本文件,自已按键手痛。于是写了个自动向键盘缓冲区放UP和
DOWN键值的程序。
; <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
; 文件名: AutoKey.asm
; 功 能: 自动向键盘缓冲区填充RIGHT 或 DOWN 键值 来移动光标
; Ctrl + Tab 停止填充
; Ctrl + RIGHT 填充RIGHT 键值
; Ctrl + DOWN 填充DOWN 键值
; Ctrl + UP 提高填充速度
; Ctrl + LEFT 降低填充速度
;
; 作 者: 黄志斌 2003年2月 广西河池
;
; 申 明: 可以自由转载,应保存完整性.且不能用于商业用途
;
; 说 明:
; 1. 第一次运行时常驻内存,再次运行则撤出内存
; 2. 适用于QE.EXE 和 TC.EXE, 不适于 EDIT.COM
; 3. 改进方向:
; A 在屏幕右上角显示当前速度
; B 填充RIGHT 键值时能自动换行
; 开发环境: IBM PC 486, MSDOS7.0(mswin95), MASM生成
; Log
; -----------------------------------------------------------------------
; 2003.02.24 Created, but the result is exception!
; 2003.02.25 OK!<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
<

cseg segment
;==============================
org 100h
assume es: cseg, ss: cseg
assume cs: cseg, ds: cseg

UP EQU 48h
Left EQU 4bh
RIGHT EQU 4dh
DOWN EQU 50h

Ctrl EQU 04h
Alt EQU 08h
EndKey EQU 4fh
Tab EQU 0Fh
AddKey EQU 0dh
DecKey EQU 0ch

RightDelay equ 10
DownDelay equ 100

;-----------------------------
start: jmp @Init
;====================
Old1cAddr label dword
Old1cOff dw ?
Old1cSeg dw ?
Old09Addr label dword
Old09Off dw ?
Old09Seg dw ?
mcb_evb dw ? ; mcb: Memmory Control Block
mcb_psp dw ?
show dw 1
count dw 0
FillKey db 0
time dw 0
AutoKey label word
db 00
KeyCode db RIGHT

VarLen equ $ - Old1cAddr

;---------------
new09h proc far
sti
push ax
push bx
push ds

mov ax, 0040h
mov ds, ax
mov bh, ds:[017h]
push cs
pop ds
test bh, Ctrl
jz @old09
in al, 60h
cmp al, Tab ;EndKey
jne @right
mov FillKey, 0
mov KeyCode, 0
jmp @Old09
@right:
cmp al, RIGHT
jnz @down
mov byte ptr KeyCode, RIGHT
mov time, RightDelay
jmp @AutoON
@down:
cmp al, DOWN
jnz @up
mov byte ptr KeyCode, DOWN
mov time, DownDelay
jmp @AutoON
@up:
cmp al, UP
jnz @left
cmp word ptr time, 1
je @Old09
dec time
jmp @ClrCount ;jmp @Old09
@left:
cmp al, LEFT
jnz @Old09
cmp word ptr time, 0ffffh
je @Old09
inc time
;jmp @ClrCount
@AutoON:
mov FillKey, 1
@ClrCount:
mov count, 0
@Old09:
pop ds
pop bx
pop ax
jmp cs:Old09Addr
new09h endp

new1ch proc far
cmp byte ptr cs:FillKey, 1
jne @Old1c

push ds

push cs
pop ds
inc count
mov ax, time
cmp ax, count
jne n1c

mov count, 0
push ax
push bx

mov ax, 0040h
mov ds, ax
cli

mov bx, word ptr ds:[001ch]
mov ax, cs: AutoKey
mov [bx], ax
inc bx
inc bx

cmp bx, 003eh
jnz @NoTail
mov bx, 001eh
@NoTail:
mov ax, bx
mov bx, 001ch
mov [bx], ax

sti
pop bx
pop ax
n1c:
pop ds
@Old1c:
jmp cs:Old1cAddr
new1ch endp

@Init:
mov ax, 3509h ; Get current 1ch interrupt vector
int 21h

cmp bx, offset new09h ; Has been Intalled?
jnz @install ; No install

mov dx, offset strMsgUninstall
mov ah, 09h
int 21h

mov bx, 1ch * 04h ; Restore old 1ch interrupt vector
xor ax, ax ; to System interrupt vector talbe
mov ds, ax
mov ax, es:[Old1cOff]
mov ds:[bx], ax
mov ax, es:[Old1cSeg]
mov ds:[bx+2], ax

mov bx, 09h * 04h ; Restore old 09h interrupt vector
mov ax, es:[Old09Off] ; to System interrupt vector talbe
;xor ax, ax
;mov ds, ax ; ds must equal 0
mov ds:[bx], ax
mov ax, es:[Old09Seg]
mov ds:[bx+2], ax

mov bx, 1 ; Release evirenment parameter block
mov ax, es:[mcb_evb]
mov ds, ax
mov word ptr ds:[bx], 0

mov ax, es:[mcb_psp] ; Release TSR
mov ds, ax
mov word ptr ds:[bx], 0
mov ax, 4c00h
int 21h

@install:
;mov ax, 3509h ; Get current 1ch interrupt vector
;int 21h
mov Old09Seg, es ; Store current 09h interrupt vector
mov Old09Off, bx

mov dx, offset new09h ; Set new 09h interrupt vector
mov ax, 2509h
int 21h

mov ax, 351ch ; Get current 1ch interrupt vector
int 21h
mov Old1cSeg, es ; Store current 1ch interrupt vector
mov Old1cOff, bx

mov dx, offset new1ch ; Set new 1ch interrupt vector
mov ax, 251ch
int 21h

mov dx, offset strMsgInstall
mov ah, 09h
int 21h

; Store the address of evirenment parameter block
mov ax, cs
dec ax
mov [mcb_psp], ax ;mov cs:[mcb_psp], ax
mov bx, 2ch
mov ax, [bx] ;mov ax, cs:[bx]
dec ax
mov cs:[mcb_evb], ax

mov dx, offset @Init
add dx, VarLen + 2
mov cl, 04h
shr dx, cl
mov ax, 3100h
int 21h
;====================
strMsgInstall db 07h, "AutoKey installed!$"
strMsgUninstall db 07h, "AutoKey uninstalled!$"
cseg ends
end start