c99-compat.c

   1 /*
   2  * Simple implementations of some C99 library functions.
   3  * Note that the goal of altfloat is not to create a C99 math library: these
   4  * functions are intended to just be "good enough" on platforms where they are
   5  * missing.
   6  *
   7  * Copyright (C) 2010 Nick Bowler.
   8  *
   9  * License BSD2:  2-clause BSD license.  See LICENSE for full terms.
  10  * This is free software: you are free to change and redistribute it.
  11  * There is NO WARRANTY, to the extent permitted by law.
  12  */
  13 #include <config.h>
  14 #include <limits.h>
  15 #include <math.h>
  16
  17 #if NEED_LIBM_NAN
  18 double nan(const char *tagp)
  19 {
  20         return NAN;
  21 }
  22 #endif
  23
  24 #if NEED_LIBM_LOG2
  25 double log2(double x)
  26 {
  27         return log(x) / log(2);
  28 }
  29 #endif
  30
  31 #if NEED_LIBM_EXP2
  32 double exp2(double x)
  33 {
  34         return pow(2, x);
  35 }
  36 #endif
  37
  38 #if NEED_LIBM_FMA
  39 double fma(double x, double y, double z)
  40 {
  41         return x*y + z;
  42 }
  43 #endif
  44
  45 #if NEED_LIBM_REMQUO
  46 double remquo(double x, double y, int *quo)
  47 {
  48         unsigned tmp = fabs(round(x/y));
  49         int sign     = signbit(x/y) ? -1 : 1;
  50
  51         *quo = sign * (int)(tmp % (INT_MAX + 1u));
  52         return remainder(x, y);
  53 }
  54 #endif