程序有错误 请帮忙改下
输入小写字母的时候无问题，但按下shift键或其他键时，就无反应stack segment para stack 'stack '
db 256 dup(0)
stack ends
data segment para public 'data '
buffer db 16h dup(0)
bufpt1 dw 0
bufpt2 dw 0
kbflag db 0
prompt db '---kbd_io program begin--- ',0dh,0ah, '$ '
scantab db 0,0, '1234567890-= ',8,0
db 'qwertyuiop[] ',0dh,0
db 'asdfghjkl; ',0,0,0,0
db 'zxcvbnm,./ ',0,0,0
db ' ',0,0,0,0,0,0,0,0,0,0,0,0,0
db '789-456+1230. '
shiftab db 0,0, '!@#$%^&*()_+ ',0,0
db 'QWERTYUIOP{} ',0dh,0
db 'ASDFGHJKL: " ',0,0,0
db 'ZXCVBNM <> ? ',0,0,0
db ' ',26 dup(0)
even
oldcs9 dw ?
oldip9 dw ?
data ends
code segment para public 'code '
start proc far
assume cs:code,ds:data
push ds
mov ax,0
push ax
mov ax,data
mov ds,ax
cli
mov al,09
mov ah,35
int 21h
mov oldcs9,es
mov oldip9,bx
push ds
mov dx,offset kbint
mov ax,seg kbint
mov ds,ax
mov al,09
mov ah,25h
int 21h
pop ds
in al,21h
and al,0fdh
out 21h,al
mov dx,offset prompt
mov ah,9
int 21h
sti
forever: call kbget
test kbflag,02h
jnz forever
test kbflag,80h
jnz endint
push ax
call dispchar
pop ax
cmp al,0dh
jnz forever
mov al,0ah
call dispchar
jmp forever
endint:
mov dx,oldip9
mov ax,oldcs9
mov ds,ax
mov al,09h
mov ah,25h
int 21h
ret
start endp
kbget proc near
push bx
cli
mov bx,bufpt1
cmp bx,bufpt2
jnz kbget2
cmp kbflag,0
jnz kbget3
sti
pop bx
jmp kbget
kbget2:
mov al,[buffer+bx]
inc bx
cmp bx,16
jc kbget3
mov bx,0
kbget3:
mov bufpt1,bx
pop bx
ret
kbget endp
kbint proc far
push bx
push ax
in al,60h
push ax
in al,61h
or al,80h
out 61h,al
and al,7fh
out 61h,al
pop ax
test al,80h
jnz kbint2
cmp al,42d
jne qq
mov kbflag,02h
jmp kbint2
qq: test kbflag,02h
je uu
mov bx,offset shiftab
xlat shiftab
jmp kk
uu: mov bx,offset scantab
xlat scantab
kk: cmp al,0
jnz kbint4
mov kbflag,80h
jmp kbint2
kbint4:
mov bx,bufpt2
mov [buffer+bx],al
inc bx
cmp bx,16
jc kbint3
mov bx,0
kbint3:
cmp bx,bufpt1
jz kbint2
mov bufpt2,bx
kbint2:
cli
mov al,20h
out 20h,al
pop ax
pop bx
sti
iret
kbint endp
dispchar proc near
push bx
mov bx,0
mov ah,0eh
int 10h
pop bx
ret
dispchar endp
code ends
