Back to index

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

Go to the source code of this file.

Functions

float __nexttowardf (float x, long double y)
 long_double_symbol (libm, __nexttowardf, nexttowardf)

Function Documentation

float __nexttowardf ( float  x,
long double  y 
)

Definition at line 29 of file s_nexttowardf.c.

{
       int32_t hx,ix;
       int64_t hy,iy;
       u_int64_t ly, uly;

       GET_FLOAT_WORD(hx,x);
       GET_LDOUBLE_WORDS64(hy,ly,y);
       ix = hx&0x7fffffff;         /* |x| */
       iy = hy&0x7fffffffffffffffLL;      /* |y| */
       uly = ly&0x7fffffffffffffffLL;     /* |y| */

       if((ix>0x7f800000) ||   /* x is nan */
          ((iy>=0x7ff0000000000000LL)&&((iy-0x7ff0000000000000LL)|uly)!=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,(u_int32_t)((hy>>32)&0x80000000)|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(hy<0||(ix>>23)>(iy>>52)-0x380
              || ((ix>>23)==(iy>>52)-0x380
                 && (ix&0x7fffff)>((hy>>29)&0x7fffff))) {/* x > y, x -= ulp */
              hx -= 1;
           } else {                       /* x < y, x += ulp */
              hx += 1;
           }
       } else {                           /* x < 0 */
           if(hy>=0||(ix>>23)>(iy>>52)-0x380
              || ((ix>>23)==(iy>>52)-0x380
                 && (ix&0x7fffff)>((hy>>29)&0x7fffff))) {/* 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) {         /* underflow */
           float u = x*x;
           math_force_eval (u);    /* raise underflow flag */
       }
       SET_FLOAT_WORD(x,hx);
       return x;
}