nasm vs汇编混编

Using Assembly from Microsoft Visual C++ 2010

Dr. Orion Lawlor, 2011-10-12

Step 1: Write C++ Code

First, hit File - New Project to make a standard C++ console application:

Next, remove the Microsoft junk, like the procompiled header.

Next, write some test C++ code. It helps to run at this point, to make sure everything works.

Step 2: Write assembly code

Now write an assembly language source file with these critical pieces:

• Give the file the .S extension, the standard extension for assembly code.
• Start the file with "section .text", so the code is executable.
• Make the function "global", so the linker can see it.
• Make the function name begin with an underscore--for some reason Windows compilers stick an underscore on the front of every function name.

Finally, right click on your new file, and hit properties.

Visual doesn't know how to compile the .S file by default, so it ignores it: "Does not participate in build." Change this to "Custom Build Tool":  Now you need to download and install NASM(or YASM, etc.) You then give Visual Studio the Command Line needed to run your assembler, just like at the DOS prompt:

	"\Program Files\nasm\nasm" -f win32  asmstuff.S

The assembler will output a .obj file, which you list under "Outputs".

Build the project, and you should be able to call assembly functions from your C++, and vice versa!  Don't forget extern "C" from C++!

Simple C++ code:

#include 
extern "C" int foo(void); // written in assembly!

int main() {
	std::cout<<"Foo returns "< 
  Assembly code: 
  
section .text ; makes this executable
global _foo ; makes this visible to linker
_foo:
	mov eax,7 ; just return a constant
	ret