hypotf.c raw

   1  #include <math.h>
   2  #include <stdint.h>
   3  
   4  float hypotf(float x, float y)
   5  {
   6  	union {float f; uint32_t i;} ux = {x}, uy = {y}, ut;
   7  	float_t z;
   8  
   9  	ux.i &= -1U>>1;
  10  	uy.i &= -1U>>1;
  11  	if (ux.i < uy.i) {
  12  		ut = ux;
  13  		ux = uy;
  14  		uy = ut;
  15  	}
  16  
  17  	x = ux.f;
  18  	y = uy.f;
  19  	if (uy.i == 0xff<<23)
  20  		return y;
  21  	if (ux.i >= 0xff<<23 || uy.i == 0 || ux.i - uy.i >= 25<<23)
  22  		return x + y;
  23  
  24  	z = 1;
  25  	if (ux.i >= (0x7f+60)<<23) {
  26  		z = 0x1p90f;
  27  		x *= 0x1p-90f;
  28  		y *= 0x1p-90f;
  29  	} else if (uy.i < (0x7f-60)<<23) {
  30  		z = 0x1p-90f;
  31  		x *= 0x1p90f;
  32  		y *= 0x1p90f;
  33  	}
  34  	return z*sqrtf((double)x*x + (double)y*y);
  35  }
  36