c - 调用c函数时出现段错误

Question

我是 x86-64 汇编的新手，我正在运行一个简单的 x64 汇编代码:

.global main

.text
main:                                
    mov     $message, %rdi       
    sub     $8, %rsp             
    call    puts                 
    add     $8, %rsp             
    ret                          
message:
    .asciz "Hello, World"        

在cygwin下用gcc编译代码后，总是报错:

segmentation error

但如果我删除

call puts

程序运行没有错误。那么这个call out语句有什么问题呢？

Answer 1

您必须在只读数据部分定义message...
像这样...

.rodata                               # read-only data section
message:
    .string    "Hello, World!"

在 32 位机器上，使用 AT&T 语法，代码如下...

.section .rodata
msg:
    .string    "Hello, World!"        # msg is in the read only data section.

.section .text
    .globl    main
    .type     main, @function
main:
    pushl    %ebp
    movl     %esp, %ebp
    andl     $-16, %esp
    subl     $16,  %esp

    movl     $msg, (%esp)             # We move the argument of puts to (%esp)
    call     puts                     # puts is called

    movl     $0,   (%esp)             # moved the argument of(0) exit to (%esp)
    call     exit                     # exit is called