test.c

#include <stdio.h>
#include <math.h>
// #### #### #### #### . #### #### #### #### - 32bit 
// Sbit 15bit . 16bit 
#define FX_Q_NUM 16
#define FX_2_MINUS_16 1.52587890625e-05F
#define FX_2_PLUS_16 (1<<16)
#define FX_S_15_16 11516 // 1:singed 15 16
#define FX_SYSTEM FX_S_15_16

typedef int fixed32;


fixed32 fromFloat(float fa)
{
	return (fixed32) (fa * FX_2_PLUS_16);
}
float toFloat(fixed32 xa)
{
	return ((float) (xa)) * FX_2_MINUS_16;
}
fixed32 fxAdd(fixed32 a, fixed32 b)
{
	//return fromFloat((toFloat(a) + toFloat(b)));
	return  (fixed32)
		( FX_2_PLUS_16 * 
	       	(((float) (a)) * FX_2_MINUS_16) + 
		(((float) (b) * FX_2_MINUS_16))
		);
}
fixed32 fxAdd2(fixed32 a, fixed32 b)
{
	return a+b;
}

int main()
{
	long long i=0;
	int ia, ib, ic, ic2;
	float fa;
	//fscanf(stdin, "%d %d", &ia, &ib);
	for (i=0; i< (long long)256*256*256*256; i+=(25))
	{
		ic = fxAdd(i, i);
		ic2 = fxAdd2(i, i);
		//fprintf(stdout, "%f + %f : %f, %f diff=%d\n", toFloat(i), toFloat(i),toFloat(ic),toFloat(ic2),ic-ic2);
	}

}