Question

输入空格字符后，输入打印有点困难。到目前为止，我有它显示输入的大写/小写但是一旦我输入一个字符串，它不会读取白色空格字符后的什么。有什么建议吗？

编辑：intel x86处理器和im使用EMU8086

org 100h

include 'emu8086.inc'
printn "Enter string to convert" 
mov dx,20
call get_string

printn
mov bx,di
mov ah,0eh

mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower1
cmp al, 61h
cmp al, 7ah
jle ToUpper1

ToLower1:
add al, 20h
int 10h
jmp stop1
ToUpper1:
sub al, 20h
int 10h
stop1:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower2
cmp al, 61h

cmp al, 7ah
jle ToUpper2

ToLower2:
add al, 20h
int 10h
jmp stop2
ToUpper2:
sub al, 20h
int 10h
stop2:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower3
cmp al, 61h

cmp al, 7ah
jle ToUpper3

ToLower3:
add al, 20h
int 10h
jmp stop3
ToUpper3:
sub al, 20h
int 10h
stop3:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower4
cmp al, 61h

cmp al, 7ah
jle ToUpper4

ToLower4:
add al, 20h
int 10h
jmp stop4
ToUpper4:
sub al, 20h
int 10h
stop4:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower5
cmp al, 61h
cmp al, 7ah
jle ToUpper5

ToLower5:
add al, 20h
int 10h
jmp stop5
ToUpper5:
sub al, 20h
int 10h
stop5:



printn
hlt
define_get_string
define_print_string
end

Answer 1

@Oded，这些寄存器是x86，emu8086意味着8086 CPU的仿真器。

@OP：那么你在字符代码中添加32可以使它更低吗？ space的ASCII码是32，@符号的ASCII码是64吗？这应该告诉你你的比较在某处是错误的。

cmp al, 41h ;A
; WHAT ARE YOU MISSING HERE?
cmp al, 5Ah ;Z
jle ToLower1

cmp al, 61h ;a
; WHAT ARE YOU MISSING HERE?
cmp al, 7ah ;z
jle ToUpper1

你看到错误吗？这基本上告诉CPU当前字符是否等于或小于Z以降低。此外，如果字符等于或小于z以使上面。

所以你拥有的是：

您需要cmp al, 41H后的条件跳转和cmp al, 61H

之后的条件跳转

但这仍然行不通，这应该有效：

cmp     al, 41H
jb      CheckForLower
cmp     al, 5AH
ja     CheckForLower
; convert to lowercase here
; Process next char

cmp     al, 61H
jb      NotValid
cmp     al, 7AH
ja      NotValid
; convert to uppercase here
; Process next char

*编辑* 我们可以将所有代码压缩成1循环：

org 100h

include 'emu8086.inc'
printn "Enter string to convert" 
    mov     dx,20
    call    get_string

printn
    mov     bx, di
    mov     ah,0eh 

    jmp     Start  

NextChar:
    inc     bx 

Start:
    mov     al, [ds+bx]   
    test    al, al
    jz      stop5      

    cmp     al, 20H    
    je      PrintChar   

    cmp     al, 41H    
    jb      CheckLower  
    cmp     al, 5AH
    ja      CheckLower
    add     al, 20H   
    int     10H
    jmp     NextChar

CheckLower:
    cmp     al, 61H
    jb      NextChar
    cmp     al, 7AH
    ja      NextChar
    sub     al, 20H           

PrintChar:
    int     10H
    jmp     NextChar 

stop5:
    printn  
    hlt
    define_get_string
    define_print_string
end

汇编语言bug与空格字符

1 个答案: