unistd.c

一个操作系统的源码部分

#include "unistd.h"

int int386(int eax, unsigned ebx, unsigned ecx, unsigned edx)
{
	int ret_val;

	__asm__ __volatile__("int %1\n"
		: "=a"(ret_val)		/* EAX	    EBX		ECX		EDX */
		: "i"(0x80), "a"((unsigned)eax), "b"(ebx), "c"(ecx), "d"(edx));

	return ret_val;
}