Calling convention in C

Several common calling conventions:

Calling convention	Parameter stacking order	Balance stack
__cdecl	Stack from right to left	The caller cleans up the stack (who calls, who balances the stack, also known as the external flat stack)
__stdcall	Stack from right to left	Clean up the stack by itself (stack balancing within the function, also known as internal flat stack)
__fastcall	ECX/EDX transmits the first two	Clean up the stack by itself (stack balancing within the function, also known as internal flat stack)

1、c,c++默认的调用约定
int __cdecl Plus(int a, int b)				
{				
	return a+b;			
}				

//汇编				
push        2				
push        1				
call        @ILT+15(Plus) (00401014)				
add         esp,8      //这里在函数外部进行堆栈平衡				

---

2、
int __stdcall Plus(int a, int b)				
{				
	return a+b;			
}				
	
//汇编			
push        2				
push        1				
call        @ILT+10(Plus) (0040100f)				
				
函数内部：							
ret         8		//这句是在call内部，即函数内部进行的堆栈平衡		

---

3、fastcall，参数会放在寄存器中，运算速度会非常快，如果参数超过两个，那其中一个参数就会被放入到内存中，达不到提升速度的效果。因此fastcall 只有两个参数时候才有优化效果
int __fastcall Plus(int a, int b)				
{				
	return a+b;			
}				

//汇编				
mov         edx,2				
mov         ecx,1				
call        @ILT+0(Plus) (00401005)				
				
函数内部：				  				
ret         				

---

4、int __fastcall Plus4(int a, int b,int c,int d)				
{				
	return a+b+c+d;			
}				
				
push        4				
push        3				
mov         edx,2				
mov         ecx,1				
call        @ILT+5(Plus) (0040100a)				
				
函数内部：							
ret         8