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

Go to the source code of this file.

Functions

long double __nextafterl (long double x, long double y)

Function Documentation

long double __nextafterl ( long double  x,
long double  y 
)

Definition at line 35 of file s_nextafterl.c.

{
       int32_t ix,iy,esx,esy;
       u_int32_t hx,hy,lx,ly;

       GET_LDOUBLE_WORDS(esx,hx,lx,x);
       GET_LDOUBLE_WORDS(esy,hy,ly,y);
       ix = esx&0x7fff;            /* |x| */
       iy = esy&0x7fff;            /* |y| */

       if(((ix==0x7fff)&&((hx&0x7fffffff)|lx)!=0) ||   /* x is nan */
          ((iy==0x7fff)&&((hy&0x7fffffff)|ly)!=0))     /* y is nan */
          return x+y;
       if(x==y) return y;          /* x=y, return y */
       if((ix|hx|lx)==0) {                /* x == 0 */
           SET_LDOUBLE_WORDS(x,esy&0x8000,0,1);/* return +-minsubnormal */
           y = x*x;
           if(y==x) return y; else return x;     /* raise underflow flag */
       }
       if(esx>=0) {                /* x > 0 */
           if(esx>esy||((esx==esy) && (hx>hy||((hx==hy)&&(lx>ly))))) {
             /* x > y, x -= ulp */
              if(lx==0) {
                  if (ix != 0 && hx == 0x80000000) hx = 0;
                  if (hx==0) esx -= 1;
                  hx -= 1;
              }
              lx -= 1;
           } else {                       /* x < y, x += ulp */
              lx += 1;
              if(lx==0) {
                  hx += 1;
                  if (hx==0) {
                     hx = 0x80000000;
                     esx += 1;
                  }
              }
           }
       } else {                           /* x < 0 */
           if(esy>=0||esx>esy||((esx==esy) && (hx>hy||((hx==hy)&&(lx>ly))))){
             /* x < y, x -= ulp */
              if(lx==0) {
                  if (ix != 0 && hx == 0x80000000) hx = 0;
                  if (hx==0) esx -= 1;
                  hx -= 1;
              }
              lx -= 1;
           } else {                       /* x > y, x += ulp */
              lx += 1;
              if(lx==0) {
                  hx += 1;
                  if (hx==0) {
                     hx = 0x80000000;
                     esx += 1;
                  }
              }
           }
       }
       esy = esx&0x7fff;
       if(esy==0x7fff) return x+x; /* overflow  */
       if(esy==0 && (hx & 0x80000000) == 0) { /* underflow */
           y = x*x;
           if(y!=x) {              /* raise underflow flag */
               SET_LDOUBLE_WORDS(y,esx,hx,lx);
              return y;
           }
       }
       SET_LDOUBLE_WORDS(x,esx,hx,lx);
       return x;
}