段错误的指令MOVQ？ [英] Segfault on movq instruction?

问题描述

考虑下面的短节目。

  INT的main（）{
    ASM（MOVQ 0x5F5E100，RCX％;
            startofloop：;
            子为0x1，％RCX;
            JNE startofloop;）;
}
 

这个程序编译罚款，但在运行时，它出现segfaults初始 MOVQ 指令。

我必须缺少明显的东西，但我希望这里有人能指出来给我。

我运行在Debian 8内核3.16.0-4-amd64的，在相关情况。

---

对于未来的参考，这是编译器生成的。

 主：
.LFB0：
    .cfi_startproc
    pushq％RBP
    .cfi_def_cfa_offset 16
    .cfi_offset 6，-16
    MOVQ％RSP，RBP％
    .cfi_def_cfa_register 6
#APP
＃2asm_fail.c1
    MOVQ 0x5F5E100，RCX％; startofloop：;子为0x1，％RCX; JNE startofloop;
＃0，2
#NO_APP
 

解决方案

原来，它已经太长时间，因为我已经写了ASM，我忘记了与<$ C $一绝preface立即值C> $ 在AT＆amp; T公司的语法。我发现提醒这里时仔细检查AT＆amp; T公司语法。​​

  ASM（MOVQ $ 100000000，RCX％;
        startofloop：;
        子$为0x1，％RCX;
        JNE startofloop;）;
 

Consider the following short program.

int main(){                      
    asm("movq 0x5F5E100, %rcx;"  
            "startofloop: ; "    
            "sub 0x1, %rcx; "    
            "jne startofloop; ");
}                                

This program compiles fine, but when it is run, it segfaults on the initial movq instruction.

I must be missing something obvious, but I hope someone here can point it out for me.

I am running on Debian 8, with kernel 3.16.0-4-amd64, in case that is relevant.

---

For future reference, this is what the compiler generated.

main:                                                                  
.LFB0:                                                                 
    .cfi_startproc                                                     
    pushq   %rbp                                                       
    .cfi_def_cfa_offset 16                                             
    .cfi_offset 6, -16                                                 
    movq    %rsp, %rbp                                                 
    .cfi_def_cfa_register 6                                            
#APP                                                                   
# 2 "asm_fail.c" 1                                                     
    movq 0x5F5E100, %rcx;startofloop: ; sub 0x1, %rcx; jne startofloop;
# 0 "" 2                                                               
#NO_APP                                                                

解决方案

It turns out that it has been too long since I have written asm, and I had forgotten that one must preface immediate values with $ in AT&T syntax. I found the reminder here when double-checking AT&T syntax.

asm("movq $100000000, %rcx;"
        "startofloop: ; "
        "sub $0x1, %rcx; "
        "jne startofloop; ");

这篇关于段错误的指令MOVQ？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！