Back to index

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

Go to the source code of this file.

Functions

float __nextafterf (float x, float y)

Function Documentation

float __nextafterf ( float  x,
float  y 
)

Definition at line 27 of file s_nextafterf.c.

{
       int32_t hx,hy,ix,iy;

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

       if((ix>0x7f800000) ||   /* x is nan */
          (iy>0x7f800000))     /* y is nan */
          return x+y;
       if(x==y) return y;          /* x=y, return y */
       if(ix==0) {                        /* x == 0 */
           float u;
           SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */
           u = math_opt_barrier (x);
           u = u*u;
           math_force_eval (u);           /* raise underflow flag */
           return x;
       }
       if(hx>=0) {                        /* x > 0 */
           if(hx>hy) {                           /* x > y, x -= ulp */
              hx -= 1;
           } else {                       /* x < y, x += ulp */
              hx += 1;
           }
       } else {                           /* x < 0 */
           if(hy>=0||hx>hy){                     /* 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)
           asm ("" : "+m"(x));
         return x;   /* overflow  */
       }
       if(hy<0x00800000) {
           float u = x*x;                 /* underflow */
           math_force_eval (u);           /* raise underflow flag */
       }
       SET_FLOAT_WORD(x,hx);
       return x;
}