我嘗試製作一個彙編代碼,用於計算字符串中有多少個字符,但出現錯誤。通過字符串彙編循環來計算字符數
碼,我用gcc和intel_syntax
#include <stdio.h>
int main(){
char *s = "aqr b qabxx xryc pqr";
int x;
asm volatile (
".intel_syntax noprefix;"
"mov eax, %1;"
"xor ebx,ebx;"
"loop:"
"mov al,[eax];"
"or al, al;"
"jz print;"
"inc ebx;"
"jmp loop"
"print:"
"mov %0, ebx;"
".att_syntax prefix;"
: "=r" (x)
: "r" (s)
: "eax", "ebx"
);
printf("Length of string: %d\n", x);
return 0;
}
,我得到了錯誤:
Error: invalid use of register
最後,我想使程序,它搜索正則表達式([PQ] [^ A] + a)並打印它的起始位置和長度。我寫在C,但我必須讓它在裝配工作: 我的C代碼:
#include <stdio.h>
#include <string.h>
int main(){
char *s = "aqr b qabxx xryc pqr";
int y,i;
int x=-1,length=0, pos = 0;
int len = strlen(s);
for(i=0; i<len;i++){
if((s[i] == 'p' || s[i] == 'q') && length<=0){
pos = i;
length++;
continue;
} else if((s[i] != 'a')) && pos>0){
length++;
} else if((s[i] == 'a') && pos>0){
length++;
if(y < length) {
y=length;
length = 0;
x = pos;
pos = 0;
}
else
length = 0;
pos = 0;
}
}
printf("position: %d, length: %d", x, y);
return 0;
}
是否有錯誤的行號? –
你不應該在編譯器後面切換匯編語法,否則它會替換錯誤。如果您需要intel語法,請使用'-masm = intel'編譯器開關。 – Jester
7行,它開始組裝塊 –