Question

尝试运行一个简单的程序，在我的Macbook上用nasm编写。下面的代码，我已经删除了所有不必要的部分并尽可能地简化了代码。

问题：

打印txt1时，输出正确打印到stdout
打印txt2时（如下面的代码所示），不会产生输出，退出代码为0.

代码：

%define SYSCALL_EXIT  0x2000001
%define SYSCALL_WRITE 0x2000004
%define STDOUT 0x1

section .data
    txt1:  db "first line of text", 10, 0
    t1len: equ $-txt1

    txt2 db "second line of text", 10, 0
    t2len: equ $-txt2

section .text
    global _main

_main:
    call printText

    mov rax, SYSCALL_EXIT
    mov rdi, 0
    syscall

printText:
    mov rax, SYSCALL_WRITE
    mov rdi, STDOUT
    mov rsi, txt2
    mov rdx, t2len
    syscall
    ret

编译：

nasm -f macho64 -o name2.o name2.asm

链接：

gcc -o name2 name2.o -Wl,-no_pie

还尝试使用 ld ：

ld -e _main -o name2 name2.o

Nasm版本：

mac:asm-codes jabbson$ nasm -v
NASM version 2.13.02 compiled on Nov 30 2017

GCC版本：

mac:asm-codes jabbson$ gcc -v
Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 9.0.0 (clang-900.0.39.2)
Target: x86_64-apple-darwin17.3.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

-Wl，-no_pie的原因 - 没有它我收到错误：

ld: warning: PIE disabled. Absolute addressing (perhaps -mdynamic-no-pic) not allowed in code signed PIE, but used in printText from name2.o. To fix this warning, don't compile with -mdynamic-no-pic or link with -Wl,-no_pie

ld版本：

mac:asm-codes jabbson$ ld -v
@(#)PROGRAM:ld  PROJECT:ld64-305
configured to support archs: armv6 armv7 armv7s arm64 i386 x86_64 x86_64h armv6m armv7k armv7m armv7em (tvOS)
LTO support using: LLVM version 9.0.0, (clang-900.0.39.2) (static support for 21, runtime is 21)
TAPI support using: Apple TAPI version 900.0.15 (tapi-900.0.15)

在MacOS上缺少汇编程序的输出

0 个答案: