Argument passing benchmark

fib.c

#include <stdio.h>

unsigned long fib1(unsigned long n)
{
	return n < 2 ? 1 : fib1(n - 1) + fib1(n - 2);
}

unsigned long fib2(unsigned long n, unsigned long m)
{
	return n < 2 ? 1 : fib2(n - 1, m) + fib2(n - 2, m);
}

int main()
{
#if TWOARGS
	printf("%lu\n", fib2(40, 0));
#else
	printf("%lu\n", fib1(40));
#endif
	return 0;
}

onearg.c

volatile int a;

void foo(volatile int *arg)
{
	*arg = 1337;
}

int main()
{
	void (*volatile fptr)(volatile int *);

	fptr = &foo;
	for (unsigned long i = 0; i < 1000000000ul; i++) {
		fptr(&a);
	}

	return 0;
}

twoargs.c

volatile int a;
volatile int b;

void foo(volatile int *arg1, volatile int *arg2)
{
	*arg1 = 1337;
}

int main()
{
	void (*volatile fptr)(volatile int *, volatile int *);

	fptr = &foo;
	for (unsigned long i = 0; i < 1000000000ul; i++) {
		fptr(&a, &b);
	}

	return 0;
}