交换2个指针x86英特尔汇编
交换2个指针x86英特尔汇编
提问于 2013-06-11 09:46:15
我试图在中交换两个指针，它们是通过引用传递给子例程的。这就是我所拥有的：
.data
firstInputPrompt BYTE 'Enter First String: ',0
secondInputPrompt BYTE 'Enter Second String: ',0
firstString BYTE 16 DUP(0) ;string buffers
secondString BYTE 16 DUP(0)
firstPointer DWORD OFFSET firstString ;pointers
secondPointer DWORD OFFSET secondString
.code
compare PROC
push ebp ;readying stack for use
mov ebp, esp
push eax ;used for comparing chars
push ebx
push ecx
mov ebx, [ebp+12] ;ebx now a pointer to firstString
mov ecx, [ebp+8] ;ecx now a pointer to secondString
mov ebx, [ebx]
mov ecx, [ecx]
;iterate over strings
iterate:
mov al, [ebx] ;compare characters
cmp al, [ecx]
ja swap_pointers
jb end_method
mov al, [ebx]
cmp al, 0
je end_method
mov al, [ecx]
cmp al, 0
je end_method
inc ebx
inc ecx
jmp iterate
swap_pointers:
;mov ecx, [ebp+12] ;get pointers again
;mov ebx, [ebp+8]
lea ebx, dword ptr [ebp+12]
lea ecx, dword ptr [ebp+8]
end_method:
;pop used registers
pop ecx
pop ebx
pop eax
pop ebp
ret
compare ENDP我感到困惑的地方就在swap_pointers:标签之后。我想不出怎么交换这两个指针。知道我哪里做错了吗？
回答 2
Stack Overflow用户
回答已采纳
发布于 2013-06-11 09:59:52
...
;load registers with pointers
mov ebx, firstPointer
mov ecx, secondPointer
;save pointers from register, swapping content
mov firstPointer, ecx
mov secondPointer, ebx
;finisStack Overflow用户
发布于 2013-06-11 17:49:52
xor在需要时交换寄存器值
load registers with pointers
mov ebx, firstPointer
mov ecx, secondPointer
xor ebx,ecx
xor ecx ebx
xor ebx,ecx总帐
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/17035351
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