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glibc  2.9
Functions
s_nexttowardf.c File Reference
#include "math.h"
#include <math_private.h>
#include <float.h>
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Functions

float __nexttowardf (float x, long double y)

Function Documentation

float __nexttowardf ( float  x,
long double  y 
)

Definition at line 28 of file s_nexttowardf.c.

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

       GET_FLOAT_WORD(hx,x);
       GET_LDOUBLE_WORDS(esy,hy,ly,y);
       ix = hx&0x7fffffff;         /* |x| */
       iy = esy&0x7fff;            /* |y| */

       /* Intel's extended format has the normally implicit 1 explicit
          present.  Sigh!  */
       if((ix>0x7f800000) ||                     /* x is nan */
          (iy>=0x7fff&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
          return x+y;
       if((long double) x==y) return y;   /* x=y, return y */
       if(ix==0) {                        /* x == 0 */
           float u;
           SET_FLOAT_WORD(x,((esy&0x8000)<<16)|1);/* return +-minsub*/
           u = math_opt_barrier (x);
           u = u * u;
           math_force_eval (u);           /* raise underflow flag */
           return x;
       }
       if(hx>=0) {                        /* x > 0 */
           if(esy>=0x8000||((ix>>23)&0xff)>iy-0x3f80
              || (((ix>>23)&0xff)==iy-0x3f80
                 && ((ix&0x7fffff)<<8)>(hy&0x7fffffff))) {/* x > y, x -= ulp */
              hx -= 1;
           } else {                       /* x < y, x += ulp */
              hx += 1;
           }
       } else {                           /* x < 0 */
           if(esy<0x8000||((ix>>23)&0xff)>iy-0x3f80
              || (((ix>>23)&0xff)==iy-0x3f80
                 && ((ix&0x7fffff)<<8)>(hy&0x7fffffff))) {/* x < y, x -= ulp */
              hx -= 1;
           } else {                       /* x > y, x += ulp */
              hx += 1;
           }
       }
       hy = hx&0x7f800000;
       if(hy>=0x7f800000) {
         x = x+x;    /* overflow  */
         if (FLT_EVAL_METHOD != 0)
           /* Force conversion to float.  */
           asm ("" : "+m"(x));
         return x;
       }
       if(hy<0x00800000) {
           float u = x*x;                 /* underflow */
           math_force_eval (u);           /* raise underflow flag */
       }
       SET_FLOAT_WORD(x,hx);
       return x;
}