- C/C++ code
int sum( int n ) { int sum = 0; for( int i = 0; i < n; ++i ) sum += i; return sum;}
用gcc4.6.0编译( g++ -O2 -S )得到的汇编代码如下:
- Assembly code
.p2align 4,,15 .globl _Z3sumi .type _Z3sumi, @function_Z3sumi:.LFB0: xorl %eax, %eax testl %edi, %edi jle .L2 xorl %edx, %edx .p2align 4,,10 .p2align 3.L3: addl %edx, %eax addl $1, %edx cmpl %edi, %edx jne .L3 .L2: rep ret .LFE0: .size _Z3sumi, .-_Z3sumi
想请教一下最后面rep紧跟着就是ret,这里的rep的作用是什么?
------解决方案--------------------------------------------------------
man1man
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重复执行