Back to index

glibc  2.9
Functions | Variables
e_hypotl.c File Reference
#include "math.h"
#include "math_private.h"

Go to the source code of this file.

Functions

long double __ieee754_hypotl (long double x, long double y)

Variables

static const long double two600 = 0x1.0p+600L
static const long double two1022 = 0x1.0p+1022L

Function Documentation

long double __ieee754_hypotl ( long double  x,
long double  y 
)

Definition at line 58 of file e_hypotl.c.

{
       long double a,b,t1,t2,y1,y2,w,kld;
       int64_t j,k,ha,hb;

       GET_LDOUBLE_MSW64(ha,x);
       ha &= 0x7fffffffffffffffLL;
       GET_LDOUBLE_MSW64(hb,y);
       hb &= 0x7fffffffffffffffLL;
       if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
       a = fabsl(a); /* a <- |a| */
       b = fabsl(b); /* b <- |b| */
       if((ha-hb)>0x3c0000000000000LL) {return a+b;} /* x/y > 2**60 */
       k=0;
       kld = 1.0L;
       if(ha > 0x5f30000000000000LL) {    /* a>2**500 */
          if(ha >= 0x7ff0000000000000LL) {       /* Inf or NaN */
              u_int64_t low;
              w = a+b;                    /* for sNaN */
              GET_LDOUBLE_LSW64(low,a);
              if(((ha&0xfffffffffffffLL)|(low&0x7fffffffffffffffLL))==0)
               w = a;
              GET_LDOUBLE_LSW64(low,b);
              if(((hb^0x7ff0000000000000LL)|(low&0x7fffffffffffffffLL))==0)
               w = b;
              return w;
          }
          /* scale a and b by 2**-600 */
          ha -= 0x2580000000000000LL; hb -= 0x2580000000000000LL; k += 600;
          a /= two600;
          b /= two600;
          k += 600;
          kld = two600;
       }
       if(hb < 0x20b0000000000000LL) {    /* b < 2**-500 */
           if(hb <= 0x000fffffffffffffLL) {      /* subnormal b or 0 */
               u_int64_t low;
              GET_LDOUBLE_LSW64(low,b);
              if((hb|(low&0x7fffffffffffffffLL))==0) return a;
              t1=two1022;   /* t1=2^1022 */
              b *= t1;
              a *= t1;
              k -= 1022;
              kld = kld / two1022;
           } else {         /* scale a and b by 2^600 */
               ha += 0x2580000000000000LL;       /* a *= 2^600 */
              hb += 0x2580000000000000LL; /* b *= 2^600 */
              k -= 600;
              a *= two600;
              b *= two600;
              kld = kld / two600;
           }
       }
    /* medium size a and b */
       w = a-b;
       if (w>b) {
           SET_LDOUBLE_WORDS64(t1,ha,0);
           t2 = a-t1;
           w  = __ieee754_sqrtl(t1*t1-(b*(-b)-t2*(a+t1)));
       } else {
           a  = a+a;
           SET_LDOUBLE_WORDS64(y1,hb,0);
           y2 = b - y1;
           SET_LDOUBLE_WORDS64(t1,ha+0x0010000000000000LL,0);
           t2 = a - t1;
           w  = __ieee754_sqrtl(t1*y1-(w*(-w)-(t1*y2+t2*b)));
       }
       if(k!=0)
           return w*kld;
       else
           return w;
}

Here is the call graph for this function:


Variable Documentation

const long double two1022 = 0x1.0p+1022L [static]

Definition at line 53 of file e_hypotl.c.

const long double two600 = 0x1.0p+600L [static]

Definition at line 52 of file e_hypotl.c.