TSR执行后无效果

[夜A千寻]

代码如下：

cseg segment
assume cs:cseg,ds:cseg
org 100h
start:
jmp Initialize

Old_Keyboard_IO dd ?

;---------------------------------------
new_keyboard_io proc far

assume cs:cseg,ds:cseg
sti
cmp ah,0
je ki0

assume ds:nothing
jmp Old_Keyboard_IO
ki0:
pushf
assume ds:nothing

cmp al,'y'
jne ki1
mov al,'Y'
jmp kidone
ki1:
cmp al,'Y'
jne kidone
mov al,'y'
kidone:
call Old_Keyboard_IO
iret
new_keyboard_io endp
;----------------------------------------------

Initialize:
assume cs:cseg,ds:cseg
mov bx,cs
mov ds,bx
mov al,16h
mov ah,35h
int 21h
mov word ptr Old_Keyboard_IO,bx
mov word ptr Old_Keyboard_IO[2],es


mov dx,offset new_keyboard_io
mov al,16h
mov ah,25h
int 21h
mov dx,offset Initialize
int 27h
cseg ends
end start

目的：将y转化为Y，将Y转化为y
但是我却没有实现它的效果，可能的问题会是什么呢？

[autotyx]

太复杂了,看不懂.

code segment
assume cs:code
org 100h
start:
mov ah,8
int 21h
cmp al,'y'
je tiao1
cmp al,'Y'
jne tiao2
mov al,'y'
jmp tiao2
tiao1:
mov al,'Y'
tiao2:
mov dl,al
mov ah,2
int 21h
jmp start
end start
这是一个输入字符,将'y'->'Y','Y'->'y',其他不变,输出到显示器

[xtdumpling]

的确比较奇怪!

     cseg segment
      assume cs:cseg,ds:cseg
      org  100h
     start: 
      jmp Initialize
     Old_Keyboard_IO dd ?           
     new_keyboard_io proc far
      assume cs:cseg,ds:cseg
      sti     
           ;Section 1
      cmp ah,0
      je ki0
      cmp ah,10h;;;
      je ki0;;;
      assume ds:nothing
      jmp  Old_Keyboard_IO
           ;Section 2
     ki0:
      pushf
      assume  ds:nothing
      call  Old_Keyboard_IO
      cmp  al,'y'
      jne  ki1
      mov  al,'Y'
      jmp  kidone
     ki1: 
      cmp  al,'Y'
      jne  kidone
      mov  al,'y'
     kidone:      
      iret
     new_keyboard_io endp 
           ;Section 3
     Initialize:
      assume cs:cseg,ds:cseg
      mov bx,cs
      mov ds,bx
      mov al,16h
      mov ah,35h
      int 21h
      mov word ptr Old_Keyboard_IO,bx
      mov word ptr Old_Keyboard_IO[2],es
           ;End Section 3
      mov dx,offset new_keyboard_io
      mov al,16h
      mov ah,25h
      int 21h
      mov dx,offset Initialize
      int 27h
     cseg ends
      end start

看这里https://forum.eviloctal.com/thread-727-1-15.html

Inp.:
AH = 10h
Return: AH = BIOS scan code
AL = ASCII character
Notes: if no keystroke is available, this function waits until one is placed
in the keyboard buffer
the BIOS scan code is usually, but not always, the same as the hardware
scan code processed by INT 09. It is the same for ASCII keystrokes
and most unshifted special keys (F-keys, arrow keys, etc.), but
differs for shifted special keys.

unlike AH=00h, this function does not discard extended keystrokes
INT 16/AH=09h can be used to determine whether this function is
supported, but only on later model PS/2s
SeeAlso: AH=00h,AH=09h,AH=11h,AH=20h,MEM 0040h:0019h,MEM 0040h:001Eh
INT 16

Copied from Ralf Brown's Interrupt List

[平台想钱想疯了]

up一下。。。