mac os X 下用nasm大杂烩

最新推荐文章于 2022-07-12 20:41:38 发布

这个教堂修了很久

最新推荐文章于 2022-07-12 20:41:38 发布

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本文链接：https://blog.youkuaiyun.com/qq_43678568/article/details/86358221

本文介绍了在Mac OS X 10.8.3上使用nasm编译64位汇编代码时遇到的问题及解决方法，包括PIE安全特性、x86_64系统调用接口的改变。通过学习，了解了如何使用新的'syscall'指令，以及在Mac OS X上正确传递参数和调用系统调用。

section .data    msg db 'This is a test', 10, 0    ; something stupid here    ft db 'addr is %x',10,0section .text    global _main    extern _printf    extern _exit_main:    push    rbp    mov     rbp, rsp           ;xor     al, al    mov     rdi, ft    ;lea rdi,[rel ft]    mov rsi,rdi    call    _printf ;xor rax,rax ;mov [rax],rax xor rdi,rdi call _exit    ;mov     rsp, rbp    ;pop     rbp    ret

mac OS X 10.8.3:

nasm -f macho x.asm

gcc -o x x.o

会出现警告：

ld: warning: PIE disabled. Absolute addressing (perhaps -mdynamic-no-pic) not allowed in code signed PIE, but used in _main from a.o. To fix this warning, don't compile with -mdynamic-no-pic or link with -Wl,-no_pie

由于安全问题，解释如下：

所谓的PIE是指position independent executable，即地址无关exe，换句话说也就是生成的机器码中不能出现lea rax, some_symbol_name这样的绝对寻址，而只能以：lea rax, [rel some_symbol_name]这种形式出现，目的是为了提高安全性，这样OS可以以随机的地址加载exe。

采用相对地址定位即可：使用第16行指令代替。

x64 API接口有用的提示：

Mac OS X complies to the System V ABI - AMD64 Architecture Processor Supplement. It mandates that the fist 6 integer/pointer arguments are passed in RDI, RSI, RDX, RCX, R8 and R9, exactly in that order. The first 8 floating-point or vector arguments go into XMM0, XMM1, ..., XMM7. Only after all the available registers are depleted or there are arguments that cannot fit in any of those registers (e.g. a 80-bit long double value) the stack is used. 64-bit pushes are performed using MOV (the QWORDvariant) and not PUSH. Simple return values are passed back in the RAX register. The caller must also provide stack space for the callee to save some of the registers.

printf is a special function because it takes variable number of arguments. When calling such functions RAX should be set to the number of floating-point arguments, passed in the vector registers. Also note that RIP-relative addressing is preferred for data that lies within 2 GiB of the code.

关于mac OS X系统调用号有用提示：