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/*!
* \file
* \brief Implementation of a base class for fixed-point data types
* \author Johan Bergman
*
* -------------------------------------------------------------------------
*
* IT++ - C++ library of mathematical, signal processing, speech processing,
* and communications classes and functions
*
* Copyright (C) 1995-2008 (see AUTHORS file for a list of contributors)
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* -------------------------------------------------------------------------
*/
#include <itpp/fixed/fix_base.h>
#include <itpp/base/itassert.h>
#include <iostream>
namespace itpp {
// Definition and initialization of static data member
output_mode Fix_Base::outputmode = OUTPUT_FIX_SHIFT;
void Fix_Base::set_output_mode(std::string o)
{
if (o == "OUTPUT_FIX")
outputmode = OUTPUT_FIX;
else if (o == "OUTPUT_FIX_SHIFT")
outputmode = OUTPUT_FIX_SHIFT;
else if (o == "OUTPUT_FLOAT")
outputmode = OUTPUT_FLOAT;
else if (o == "OUTPUT_FLOAT_SHIFT")
outputmode = OUTPUT_FLOAT_SHIFT;
else
it_error("Fix_Base::set_output_mode: Illegal output mode!");
}
void Fix_Base::print() const
{
std::cout << "shift = " << shift << std::endl
<< "wordlen = " << wordlen << std::endl
<< "int(emode) = " << int(emode) << std::endl
<< "int(omode) = " << int(omode) << std::endl
<< "int(qmode) = " << int(qmode) << std::endl
<< "stat_ptr = " << stat_ptr << std::endl
<< "min = " << min << std::endl
<< "max = " << max << std::endl
<< "n_unused_bits = " << n_unused_bits << std::endl;
}
void Fix_Base::init()
{
switch (emode) {
case TC:
it_assert_debug(wordlen >= 1 && wordlen <= 64, "Fix_Base::calc_apply_o_modes: Illegal word length!");
max = fixrep(UINT64_POW2[wordlen - 1] - 1);
min = -max - 1;
break;
case US:
it_assert_debug(wordlen >= 0 && wordlen <= 63, "Fix_Base::calc_apply_o_modes: Illegal word length!");
min = 0;
max = fixrep(UINT64_POW2[wordlen] - 1);
break;
default:
it_error("Fix_Base::init: Illegal sign encoding mode!");
break;
}
n_unused_bits = MAX_WORDLEN - wordlen;
}
fixrep Fix_Base::apply_o_mode(fixrep x) const
{
fixrep ret = x;
bool overflow = false;
if (ret < min) {
overflow = true;
switch (omode) {
case WRAP:
ret = fixrep((fixrep(ret) << n_unused_bits) >> n_unused_bits);
break;
case SAT:
ret = min;
break;
default:
it_error("Fix_Base::apply_o_mode: Illegal overflow mode!");
break;
}
}
else if (ret > max) {
overflow = true;
switch (omode) {
case WRAP:
ret = fixrep((fixrep(ret) << n_unused_bits) >> n_unused_bits);
break;
case SAT:
ret = max;
break;
default:
it_error("Fix_Base::apply_o_mode: Illegal overflow mode!");
break;
}
}
if (stat_ptr != 0)
stat_ptr->sample(double(ret), overflow);
return ret;
}
fixrep Fix_Base::scale_and_apply_modes(double x, q_mode q) const
{
it_assert_debug(shift>=-64 && shift<=63, "Fix_Base::scale_and_apply_modes: Illegal shift!");
fixrep ret = 0;
double scaled_value = x*DOUBLE_POW2[shift + 64];
switch (q) {
case RND:
ret = apply_o_mode(fixrep(std::floor(scaled_value + 0.5)));
break;
case RND_ZERO:
if (x < 0)
ret = apply_o_mode(fixrep(std::floor(scaled_value + 0.5)));
else
ret = apply_o_mode(fixrep(-std::floor(-scaled_value + 0.5)));
break;
case RND_MIN_INF:
ret = apply_o_mode(fixrep(-std::floor(-scaled_value + 0.5)));
break;
case RND_INF:
if (x < 0)
ret = apply_o_mode(fixrep(scaled_value - 0.5));
else
ret = apply_o_mode(fixrep(scaled_value + 0.5));
break;
case RND_CONV:
if (scaled_value == std::floor(scaled_value) + 0.5)
ret = apply_o_mode((fixrep(round(scaled_value)) >> 1) << 1);
else
ret = apply_o_mode(fixrep(std::floor(scaled_value + 0.5)));
break;
case RND_CONV_ODD:
if (scaled_value == std::floor(scaled_value) + 0.5)
if (scaled_value < 0)
ret = apply_o_mode(((fixrep(std::ceil(scaled_value)) >> 1) << 1) - 1);
else
ret = apply_o_mode(((fixrep(std::floor(scaled_value)) >> 1) << 1) + 1);
else
ret = apply_o_mode(fixrep(std::floor(scaled_value + 0.5)));
break;
case TRN:
ret = apply_o_mode(fixrep(std::floor(scaled_value)));
break;
case TRN_ZERO:
ret = apply_o_mode(fixrep(scaled_value));
break;
default:
it_error("Fix_Base::scale_and_apply_modes: Illegal quantization mode!");
break;
}
return ret;
}
fixrep Fix_Base::rshift_and_apply_q_mode(fixrep x, int n, q_mode q) const
{
it_assert_debug(n >= 0, "Fix_Base::rshift_and_apply_q_mode: n cannot be negative!");
fixrep ret = 0;
if (n == 0) {
ret = x;
}
else {
switch (q) {
case RND:
// Add the most significant deleted bit to the remaining bits
ret = ((x >> (n - 1)) + 1) >> 1;
break;
case RND_ZERO:
// If the most significant deleted bit is 1,
// and either the sign bit or at least one other deleted bit is 1,
// add 1 to the remaining bits
if ((x & (fixrep(1) << (n - 1))) && ((x < 0) || (x & ((fixrep(1) << (n - 1)) - 1))))
ret = (x >> n) + 1;
else
ret = x >> n;
break;
case RND_MIN_INF:
// If the most significant deleted bit is 1,
// and at least one other deleted bit is 1,
// add 1 to the remaining bits
if ((x & (fixrep(1) << (n - 1))) && (x & ((fixrep(1) << (n - 1)) - 1)))
ret = (x >> n) + 1;
else
ret = x >> n;
break;
case RND_INF:
// If the most significant deleted bit is 1,
// and either the inverted value of the sign bit or at least one other deleted bit is 1,
// add 1 to the remaining bits
if ((x & (fixrep(1) << (n - 1))) && ((x >= 0) || (x & ((fixrep(1) << (n - 1)) - 1))))
ret = (x >> n) + 1;
else
ret = x >> n;
break;
case RND_CONV:
// If the most significant deleted bit is 1,
// and either the least significant of the remaining bits or at least one other deleted bit is 1,
// add 1 to the remaining bits
if ((x & (fixrep(1) << (n - 1))) && ((x & (fixrep(1) << n)) || (x & ((fixrep(1) << (n - 1)) - 1))))
ret = (x >> n) + 1;
else
ret = x >> n;
break;
case RND_CONV_ODD:
// If the most significant deleted bit is 1,
// and either the least significant of the remaining bits is 0 or at least one other deleted bit is 1,
// add 1 to the remaining bits
if ((x & (fixrep(1) << (n - 1))) && (!(x & (fixrep(1) << n)) || (x & ((fixrep(1) << (n - 1)) - 1))))
ret = (x >> n) + 1;
else
ret = x >> n;
break;
case TRN:
// Just copy the remaining bits
ret = x >> n;
break;
case TRN_ZERO:
// If the sign bit is 1,
// and either the most significant deleted bit or at least one other deleted bit is 1,
// add 1 to the remaining bits
if ((x < 0) && (x & ((fixrep(1) << n) - 1)))
ret = (x >> n) + 1;
else
ret = x >> n;
break;
default:
it_error("Fix_Base::rshift_and_apply_q_mode: Illegal quantization mode!");
break;
}
}
if (stat_ptr != 0)
stat_ptr->sample(double(ret), false);
return ret;
}
} // namespace itpp
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