如何比较 x86 程序集中的字符

Question

I have the two words stored in variables just called first and second. How do I compare the characters of each string to see which one is larger?

section .data

greet: db "Type a word: "
greetL: equ $-greet

section .bss

first: resb 20
second: resb 20

section .text

global _start

_start:
    nop
    mov eax, 4
    mov ebx, 1
    mov ecx, greet
    mov edx, greetL
    int 80H

    mov eax, 3
    mov ebx, 0
    mov ecx, first
    mov edx, 20
    int 80H

then I just do the same thing to get the second word

Answer 1

I dunno, cmp I suppose...

 xor ecx, ecx ; index top mov al, [first + ecx] cmp [second + ecx], al jb first_is_bigger ja second_is_bigger cmp al, LF ; LF equ 10 je they_are_equal inc ecx jmp top

That's untested. I've been having a lot of brain flatulence lately - better check me. If the pesky user enters more than 20 characters, you may be in deep muddy water...