Question

我想将ax与5进行比较，如果该值大于5，则会显示错误框。如果没有，它只会打印该号码。但即使我输入，它总是表明该值大于5.问题来自哪里？

.386 
.model flat,stdcall 
option casemap:none 

include c:\masm32\include\windows.inc
include \masm32\include\kernel32.inc 
includelib \masm32\lib\kernel32.lib 
include \masm32\include\masm32.inc
includelib \masm32\lib\masm32.lib

.data 
msg db "Enter Number", 0
msg1 db "The value is too large", 0

.data? 
input db 150 dup(?)
output db 150 dup(?)
.code 


start: 
push offset msg
call StdOut 

push 100
push offset input
call StdIn

lea ax, input
cmp ax, 5
jg Toolarge


exit:
    push 0
    call ExitProcess 

 Toolarge:
     push offset msg1
     call StdOut
     jmp start

end start

Answer 1

MASM32附带一个帮助文件：\masm32\help\masmlib.chm。它说：

StdIn从控制台接收 text 输入并将其放入缓冲区作为参数需要。当Enter为时，该函数终止按压。

我标记了相关的单词＆＃34; text＆＃34;。因此，您将获得ASCII字符串，而不是适合AX的数字。您首先要将其转换为＆＃34;整数＆＃34;在将其与cmp进行比较之前。您可以使用MASM32函数atol：

.386
.model flat,stdcall
option casemap:none

include c:\masm32\include\windows.inc
include \masm32\include\kernel32.inc
includelib \masm32\lib\kernel32.lib
include \masm32\include\masm32.inc
includelib \masm32\lib\masm32.lib

.data
    msg db "Enter Number", 0
    msg1 db "The value is too large", 0

.data?
    input db 150 dup(?)
    output db 150 dup(?)
.code

start:

    push offset msg
    call StdOut

    push 100
    push offset input
    call StdIn

    push offset input
    call atol

    cmp eax, 5
    jg Toolarge

exit:

    push 0
    call ExitProcess

Toolarge:

    push offset msg1
    call StdOut
    jmp start

end start

Answer 2

尝试使用

mov ax, input

而不是

lea ax, input

Lea加载指向您正在寻址的项目的指针（类似于0x12345678），而mov会加载该地址的实际值。

x86 ax寄存器得到不同的值？

2 个答案: