使用nasm在64位和32位体系结构上从汇编语言调用printf [英] calling printf from assembly language on 64bit and 32bit architecture using nasm

问题描述

我想从Linux中的汇编语言调用printf函数.

I want to call printf function from assembly language in linux.

我想知道用于64位和32位汇编语言程序的方法.

i want to know the method for for 64 bit and 32 bit assembly language programs.

1)如果我想在printf中使用字符串传递32位争论和64位争论，请告诉我两种情况.我该怎么办?

1) please tell me for two cases if i want to pass a 32 bit arguement and 64 bit arguement in printf with a string. how should i do it?

2)对于x86 32位体系结构，如果我想做与第1点相同的事情.

2) for x86 32 bit architecture if i want to do the same thing as in point 1.

请告诉我代码.让我知道我是否需要针对这两种情况调整堆栈，是否只需要在寄存器中传递争论?

please tell me the code. and let me know do i need to adjust the stack for both cases and do i just need to pass the arguements in registers?

非常感谢

推荐答案

在Linux中，有两种使用汇编语言打印字符串的方法.

There are 2 ways to print a string with assembly language in Linux.

1)对于x64使用syscall，对于x86使用int 0x80.不是printf，它是内核例程.您可以在此处(x86)和

1) Use syscall for x64, or int 0x80 for x86. It's not printf, it's kernel routines. You can find more here (x86) and here (x64).

2)使用glibc中的printf.我假设您熟悉NASM程序的结构，因此这是一个

2) Use printf from glibc. I assume you are familiar with the structure of NASM program, so here is a nice x86 example from acm.mipt.ru:

global main

;Declare used libc functions
extern exit
extern puts
extern scanf
extern printf

section .text

main:

;Arguments are passed in reversed order via stack (for x86)
;For x64 first six arguments are passed in straight order
;  via RDI, RSI, RDX, RCX, R8, R9 and other are passed via stack
;The result comes back in EAX/RAX
push dword msg
call puts
;After passing arguments via stack, you have to clear it to
;  prevent segfault with add esp, 4 * (number of arguments) 
add esp, 4

push dword a
push dword b
push dword msg1
call scanf
add esp, 12
;For x64 this scanf call will look like:
;  mov rdi, msg1
;  mov rsi, b
;  mov rdx, a
;  call scanf

mov eax, dword [a]
add eax, dword [b]
push eax
push dword msg2
call printf
add esp, 8

push dword 0
call exit
add esp, 4
ret

section .data
msg  : db "An example of interfacing with GLIBC.",0xA,0
msg1 : db "%d%d",0
msg2 : db "%d", 0xA, 0

section .bss
a resd 1
b resd 1

您可以将其与nasm -f elf32 -o foo.o foo.asm组装在一起，并与gcc -m32 -o foo foo.o链接以用于x86.对于x64，只需将elf32替换为elf64，将-m32替换为-m64.请注意，您需要gcc-multilib才能使用gcc在x64系统上构建x86程序.

You can assembly it with nasm -f elf32 -o foo.o foo.asm and link with gcc -m32 -o foo foo.o for x86. For x64 just replace elf32 with elf64 and -m32 with -m64. Note than you need gcc-multilib to build x86 programs on x64 system using gcc.

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