/usr/include/gnuradio/fxpt.h is in gnuradio-dev 3.7.10.1-2+b3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 | /* -*- c++ -*- */
/*
* Copyright 2004,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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, or (at your option)
* any later version.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef INCLUDED_GR_FXPT_H
#define INCLUDED_GR_FXPT_H
#include <gnuradio/api.h>
#include <gnuradio/types.h>
#include <stdint.h>
namespace gr {
/*!
* \brief fixed point sine and cosine and friends.
* \ingroup misc
*
* fixed pt radians
* --------- --------
* -2**31 -pi
* 0 0
* 2**31-1 pi - epsilon
*/
class GR_RUNTIME_API fxpt
{
static const int WORDBITS = 32;
static const int NBITS = 10;
static const float s_sine_table[1 << NBITS][2];
static const float PI;
static const float TWO_TO_THE_31;
public:
static int32_t
float_to_fixed(float x)
{
// Fold x into -PI to PI.
int d = (int)floor(x/2/PI+0.5);
x -= d*2*PI;
// And convert to an integer.
return (int32_t) ((float) x * TWO_TO_THE_31 / PI);
}
static float
fixed_to_float (int32_t x)
{
return x * (PI / TWO_TO_THE_31);
}
/*!
* \brief Given a fixed point angle x, return float sine (x)
*/
static float
sin(int32_t x)
{
uint32_t ux = x;
int index = ux >> (WORDBITS - NBITS);
return s_sine_table[index][0] * (ux >> 1) + s_sine_table[index][1];
}
/*
* \brief Given a fixed point angle x, return float cosine (x)
*/
static float
cos (int32_t x)
{
uint32_t ux = x + 0x40000000;
int index = ux >> (WORDBITS - NBITS);
return s_sine_table[index][0] * (ux >> 1) + s_sine_table[index][1];
}
/*
* \brief Given a fixedpoint angle x, return float cos(x) and sin (x)
*/
static void sincos(int32_t x, float *s, float *c)
{
uint32_t ux = x;
int sin_index = ux >> (WORDBITS - NBITS);
*s = s_sine_table[sin_index][0] * (ux >> 1) + s_sine_table[sin_index][1];
ux = x + 0x40000000;
int cos_index = ux >> (WORDBITS - NBITS);
*c = s_sine_table[cos_index][0] * (ux >> 1) + s_sine_table[cos_index][1];
return;
}
};
} /* namespace gr */
#endif /* INCLUDED_GR_FXPT_H */
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