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glibc  2.9
Functions
e_hypotf.c File Reference
#include "math.h"
#include "math_private.h"

Go to the source code of this file.

Functions

float __ieee754_hypotf (float x, float y)

Function Documentation

float __ieee754_hypotf ( float  x,
float  y 
)

Definition at line 26 of file e_hypotf.c.

{
       float a,b,t1,t2,y1,y2,w;
       int32_t j,k,ha,hb;

       GET_FLOAT_WORD(ha,x);
       ha &= 0x7fffffff;
       GET_FLOAT_WORD(hb,y);
       hb &= 0x7fffffff;
       if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
       SET_FLOAT_WORD(a,ha);       /* a <- |a| */
       SET_FLOAT_WORD(b,hb);       /* b <- |b| */
       if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */
       k=0;
       if(ha > 0x58800000) {       /* a>2**50 */
          if(ha >= 0x7f800000) {   /* Inf or NaN */
              w = a+b;                    /* for sNaN */
              if(ha == 0x7f800000) w = a;
              if(hb == 0x7f800000) w = b;
              return w;
          }
          /* scale a and b by 2**-60 */
          ha -= 0x1e000000; hb -= 0x1e000000;    k += 60;
          SET_FLOAT_WORD(a,ha);
          SET_FLOAT_WORD(b,hb);
       }
       if(hb < 0x26800000) {       /* b < 2**-50 */
           if(hb <= 0x007fffff) {  /* subnormal b or 0 */
               if(hb==0) return a;
              SET_FLOAT_WORD(t1,0x7e800000);     /* t1=2^126 */
              b *= t1;
              a *= t1;
              k -= 126;
           } else {         /* scale a and b by 2^60 */
               ha += 0x1e000000;   /* a *= 2^60 */
              hb += 0x1e000000;    /* b *= 2^60 */
              k -= 60;
              SET_FLOAT_WORD(a,ha);
              SET_FLOAT_WORD(b,hb);
           }
       }
    /* medium size a and b */
       w = a-b;
       if (w>b) {
           SET_FLOAT_WORD(t1,ha&0xfffff000);
           t2 = a-t1;
           w  = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1)));
       } else {
           a  = a+a;
           SET_FLOAT_WORD(y1,hb&0xfffff000);
           y2 = b - y1;
           SET_FLOAT_WORD(t1,ha+0x00800000);
           t2 = a - t1;
           w  = __ieee754_sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b)));
       }
       if(k!=0) {
           SET_FLOAT_WORD(t1,0x3f800000+(k<<23));
           return t1*w;
       } else return w;
}

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