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

   1
   2 /* @(#)w_fmod.c 5.1 93/09/24 */
   3 /*
   4  * ====================================================
   5  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   6  *
   7  * Developed at SunPro, a Sun Microsystems, Inc. business.
   8  * Permission to use, copy, modify, and distribute this
   9  * software is freely granted, provided that this notice
  10  * is preserved.
  11  * ====================================================
  12  */
  13
  14 /*
  15 FUNCTION
  16 <<fmod>>, <<fmodf>>---floating-point remainder (modulo)
  17
  18 INDEX
  19 fmod
  20 INDEX
  21 fmodf
  22
  23 ANSI_SYNOPSIS
  24 #include <math.h>
  25 double fmod(double <[x]>, double <[y]>)
  26 float fmodf(float <[x]>, float <[y]>)
  27
  28 TRAD_SYNOPSIS
  29 #include <math.h>
  30 double fmod(<[x]>, <[y]>)
  31 double (<[x]>, <[y]>);
  32
  33 float fmodf(<[x]>, <[y]>)
  34 float (<[x]>, <[y]>);
  35
  36 DESCRIPTION
  37 The <<fmod>> and <<fmodf>> functions compute the floating-point
  38 remainder of <[x]>/<[y]> (<[x]> modulo <[y]>).
  39
  40 RETURNS
  41 The <<fmod>> function returns the value
  42 @ifnottex
  43 <[x]>-<[i]>*<[y]>,
  44 @end ifnottex
  45 @tex
  46 $x-i\times y$,
  47 @end tex
  48 for the largest integer <[i]> such that, if <[y]> is nonzero, the
  49 result has the same sign as <[x]> and magnitude less than the
  50 magnitude of <[y]>.
  51
  52 <<fmod(<[x]>,0)>> returns NaN, and sets <<errno>> to <<EDOM>>.
  53
  54 You can modify error treatment for these functions using <<matherr>>.
  55
  56 PORTABILITY
  57 <<fmod>> is ANSI C. <<fmodf>> is an extension.
  58 */
  59
  60 /*
  61  * wrapper fmod(x,y)
  62  */
  63
  64 #include "fdlibm.h"
  65 #include <errno.h>
  66
  67 #ifndef _DOUBLE_IS_32BITS
  68
  69 #ifdef __STDC__
  70         double fmod(double x, double y) /* wrapper fmod */
  71 #else
  72         double fmod(x,y)                /* wrapper fmod */
  73         double x,y;
  74 #endif
  75 {
  76 #ifdef _IEEE_LIBM
  77         return __ieee754_fmod(x,y);
  78 #else
  79         double z;
  80         struct exception exc;
  81         z = __ieee754_fmod(x,y);
  82         if(_LIB_VERSION == _IEEE_ ||isnan(y)||isnan(x)) return z;
  83         if(y==0.0) {
  84             /* fmod(x,0) */
  85             exc.type = DOMAIN;
  86             exc.name = "fmod";
  87             exc.arg1 = x;
  88             exc.arg2 = y;
  89             exc.err = 0;
  90             if (_LIB_VERSION == _SVID_)
  91                exc.retval = x;
  92             else
  93                exc.retval = 0.0/0.0;
  94             if (_LIB_VERSION == _POSIX_)
  95                errno = EDOM;
  96             else if (!matherr(&exc)) {
  97                   errno = EDOM;
  98             }
  99             if (exc.err != 0)
 100                errno = exc.err;
 101             return exc.retval;
 102         } else
 103             return z;
 104 #endif
 105 }
 106
 107 #endif /* defined(_DOUBLE_IS_32BITS) */