toolchain/gcc/newlib/libm/common/sf_nextafter.c

   1 /* sf_nextafter.c -- float version of s_nextafter.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #include "fdlibm.h"
  17
  18 #ifdef __STDC__
  19         float nextafterf(float x, float y)
  20 #else
  21         float nextafterf(x,y)
  22         float x,y;
  23 #endif
  24 {
  25         __int32_t       hx,hy,ix,iy;
  26
  27         GET_FLOAT_WORD(hx,x);
  28         GET_FLOAT_WORD(hy,y);
  29         ix = hx&0x7fffffff;             /* |x| */
  30         iy = hy&0x7fffffff;             /* |y| */
  31
  32         if(FLT_UWORD_IS_NAN(ix) ||
  33            FLT_UWORD_IS_NAN(iy))
  34            return x+y;
  35         if(x==y) return x;              /* x=y, return x */
  36         if(FLT_UWORD_IS_ZERO(ix)) {             /* x == 0 */
  37             SET_FLOAT_WORD(x,(hy&0x80000000)|FLT_UWORD_MIN);
  38             y = x*x;
  39             if(y==x) return y; else return x;   /* raise underflow flag */
  40         }
  41         if(hx>=0) {                             /* x > 0 */
  42             if(hx>hy) {                         /* x > y, x -= ulp */
  43                 hx -= 1;
  44             } else {                            /* x < y, x += ulp */
  45                 hx += 1;
  46             }
  47         } else {                                /* x < 0 */
  48             if(hy>=0||hx>hy){                   /* x < y, x -= ulp */
  49                 hx -= 1;
  50             } else {                            /* x > y, x += ulp */
  51                 hx += 1;
  52             }
  53         }
  54         hy = hx&0x7f800000;
  55         if(hy>FLT_UWORD_MAX) return x+x;        /* overflow  */
  56         if(hy<0x00800000) {             /* underflow */
  57             y = x*x;
  58             if(y!=x) {          /* raise underflow flag */
  59                 SET_FLOAT_WORD(y,hx);
  60                 return y;
  61             }
  62         }
  63         SET_FLOAT_WORD(x,hx);
  64         return x;
  65 }
  66
  67 #ifdef _DOUBLE_IS_32BITS
  68
  69 #ifdef __STDC__
  70         double nextafter(double x, double y)
  71 #else
  72         double nextafter(x,y)
  73         double x,y;
  74 #endif
  75 {
  76         return (double) nextafterf((float) x, (float) x);
  77 }
  78
  79 #endif /* defined(_DOUBLE_IS_32BITS) */