xt_arithmetic_util.h

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/*
 * Keywords:
 * Maintainer: Jörg Behrens <behrens@dkrz.de>
 *             Moritz Hanke <hanke@dkrz.de>
 *             Thomas Jahns <jahns@dkrz.de>
 * URL: https://doc.redmine.dkrz.de/yaxt/html/
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are  permitted provided that the following conditions are
 * met:
 *
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
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 * notice, this list of conditions and the following disclaimer in the
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 */
#ifndef XT_ARITHMETIC_UTIL_H
#define XT_ARITHMETIC_UTIL_H

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <limits.h>

#include "xt/xt_core.h"

/* simple operations on Xt_int */
static inline Xt_int
Xt_isign(Xt_int x)
{
#if (-1 >> 1) == -1
  return ((x >> (sizeof (Xt_int) * CHAR_BIT - 1)) |
          (Xt_int)((Xt_uint)(~x) >> (sizeof (Xt_int) * CHAR_BIT - 1)));
#else
  return (Xt_int)((x >= 0) - (x < 0));
#endif
}

static inline int
isign(int x)
{
#if (-1 >> 1) == -1
  return ((x >> (sizeof (x) * CHAR_BIT - 1)) |
          (int)((unsigned int)(~x) >> (sizeof (x) * CHAR_BIT - 1)));
#else
  return (x >= 0) - (x < 0);
#endif
}

static inline int
isign_mask(int x)
{
#if (-1 >> 1) == -1
  return x >> (sizeof (int) * CHAR_BIT - 1);
#else
#warning Unusual behaviour of shift operator detected.
  return (x < 0) * ~0;
#endif
}


static inline Xt_int
Xt_isign_mask(Xt_int x)
{
#if (-1 >> 1) == -1
  return x >> (sizeof (x) * CHAR_BIT - 1);
#else
#warning Unusual behaviour of shift operator detected.
  return (x < 0) * ~(Xt_int)0;
#endif
}

static inline long long
llsign(long long x)
{
#if (-1 >> 1) == -1
  return ((x >> (sizeof (x) * CHAR_BIT - 1)) |
          (long long)((unsigned long long)(~x) >> (sizeof (x) * CHAR_BIT - 1)));
#else
  return (x >= 0) - (x < 0);
#endif
}

static inline long long
llsign_mask(long long x)
{
#if (-1 >> 1) == -1
  return x >> (sizeof (x) * CHAR_BIT - 1);
#else
#warning Unusual behaviour of shift operator detected.
  return (x < 0) * ~0LL;
#endif
}

static inline int
imin(int a, int b)
{
  return a <= b ? a : b;
}

#endif

/*
 * Local Variables:
 * c-basic-offset: 2
 * coding: utf-8
 * indent-tabs-mode: nil
 * show-trailing-whitespace: t
 * require-trailing-newline: t
 * End:
 */