# scaled-num.c: conversions on ``scaled'' numbers, which are a 32-bit
#               word with 16 bits of fraction.
#
# Copyright (C) 1992, 2011 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#


#include "config.h"

#include "scaled-num.h"


#define SCALED_UNITY (1 << 16)	/* 2^16, represents 1.00000.  */


/* This prints a scaled number, rounded to five digits.  */

void
print_scaled (scaled s)
{
  scaled delta;

  if (s < 0)
    {				/* Print sign, if negative. */
      putchar ('-');
      s = -s;
    }

  printf ("%u", s / SCALED_UNITY);   /* Print integer part. */
  putchar ('.');

  s = 10 * (s % SCALED_UNITY) + 5;
  delta = 10;

  do
    {
      if (delta > SCALED_UNITY)
        s += 0100000 - (delta / 2);	/* Round the last digit. */

      printf ("%c", '0' + (s / SCALED_UNITY));
      s = 10 * (s % SCALED_UNITY);
      delta *= 10;
    }
  while (s > delta);
}


const real
scaled_to_real (scaled s)
{
  real r = (real) s / SCALED_UNITY;

  return r;
}


const scaled
real_to_scaled (real r)
{
  scaled s = r * SCALED_UNITY;

  return s;
}