toolchain/gcc/newlib/libm/math/wf_exp.c

   1 /* wf_exp.c -- float version of w_exp.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 /*
  17  * wrapper expf(x)
  18  */
  19
  20 #include "fdlibm.h"
  21 #include <errno.h>
  22
  23 #ifdef __STDC__
  24 static const float
  25 #else
  26 static float
  27 #endif
  28 o_threshold=  8.8721679688e+01,  /* 0x42b17180 */
  29 u_threshold= -1.0397208405e+02;  /* 0xc2cff1b5 */
  30
  31 #ifdef __STDC__
  32         float expf(float x)             /* wrapper expf */
  33 #else
  34         float expf(x)                   /* wrapper expf */
  35         float x;
  36 #endif
  37 {
  38 #ifdef _IEEE_LIBM
  39         return __ieee754_expf(x);
  40 #else
  41         float z;
  42         struct exception exc;
  43         z = __ieee754_expf(x);
  44         if(_LIB_VERSION == _IEEE_) return z;
  45         if(finitef(x)) {
  46             if(x>o_threshold) {
  47                 /* expf(finite) overflow */
  48 #ifndef HUGE_VAL
  49 #define HUGE_VAL inf
  50                 double inf = 0.0;
  51
  52                 SET_HIGH_WORD(inf,0x7ff00000);  /* set inf to infinite */
  53 #endif
  54                 exc.type = OVERFLOW;
  55                 exc.name = "expf";
  56                 exc.err = 0;
  57                 exc.arg1 = exc.arg2 = (double)x;
  58                 if (_LIB_VERSION == _SVID_)
  59                   exc.retval = HUGE;
  60                 else
  61                   exc.retval = HUGE_VAL;
  62                 if (_LIB_VERSION == _POSIX_)
  63                   errno = ERANGE;
  64                 else if (!matherr(&exc)) {
  65                         errno = ERANGE;
  66                 }
  67                 if (exc.err != 0)
  68                    errno = exc.err;
  69                 return exc.retval;
  70             } else if(x<u_threshold) {
  71                 /* expf(finite) underflow */
  72                 exc.type = UNDERFLOW;
  73                 exc.name = "expf";
  74                 exc.err = 0;
  75                 exc.arg1 = exc.arg2 = (double)x;
  76                 exc.retval = 0.0;
  77                 if (_LIB_VERSION == _POSIX_)
  78                   errno = ERANGE;
  79                 else if (!matherr(&exc)) {
  80                         errno = ERANGE;
  81                 }
  82                 if (exc.err != 0)
  83                    errno = exc.err;
  84                 return exc.retval;
  85             }
  86         }
  87         return z;
  88 #endif
  89 }
  90
  91 #ifdef _DOUBLE_IS_32BITS
  92
  93 #ifdef __STDC__
  94         double exp(double x)
  95 #else
  96         double exp(x)
  97         double x;
  98 #endif
  99 {
 100         return (double) expf((float) x);
 101 }
 102
 103 #endif /* defined(_DOUBLE_IS_32BITS) */