/*
 * inline-asm-sum - an example of inline assembly use
 *
 * Copyright (C) 2013  Antonio Ospite <ospite@studenti.unina.it>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>

static int sum(int a, int b)
{
#if defined(__i386__) || defined(__x86_64__)
	int ret;
	__asm__("addl %2, %1\n\t"
		: "=a"(ret)      /* %0 bound to %eax */
		: "a"(a), "r"(b) /* %1 is 'a' bound to %eax, %2 is 'b' */
		);
	return ret;
#else
	return a + b;
#endif
}

int main(void)
{
	int a;
	int b;
	int ret;

	a = 13;
	b = 27;

	ret = sum(a, b);

	printf("%d + %d = %d\n", a, b, ret);
	return 0;
}