diff options
| author | Tom Rondeau <trondeau@vt.edu> | 2013-04-17 13:43:52 -0400 |
|---|---|---|
| committer | Tom Rondeau <trondeau@vt.edu> | 2013-04-29 14:52:56 -0400 |
| commit | f3e2e07201c50033bf6c9d0c6a6f068557b4f17f (patch) | |
| tree | 140b3c2d20a951ffd4abd564c3378ee2e2f9fc7c /gnuradio-runtime/include/gnuradio/fxpt.h | |
| parent | 35303ae975a5b1bdecc2492bc96e2b8e89b62a3d (diff) | |
runtime: converting runtime core to gr namespace, gnuradio include dir.
Diffstat (limited to 'gnuradio-runtime/include/gnuradio/fxpt.h')
| -rw-r--r-- | gnuradio-runtime/include/gnuradio/fxpt.h | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/gnuradio-runtime/include/gnuradio/fxpt.h b/gnuradio-runtime/include/gnuradio/fxpt.h new file mode 100644 index 0000000000..6143acafeb --- /dev/null +++ b/gnuradio-runtime/include/gnuradio/fxpt.h @@ -0,0 +1,108 @@ +/* -*- 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> + +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 gr_int32 + 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 (gr_int32) ((float) x * TWO_TO_THE_31 / PI); + } + + static float + fixed_to_float (gr_int32 x) + { + return x * (PI / TWO_TO_THE_31); + } + + /*! + * \brief Given a fixed point angle x, return float sine (x) + */ + static float + sin(gr_int32 x) + { + gr_uint32 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 (gr_int32 x) + { + gr_uint32 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(gr_int32 x, float *s, float *c) + { + gr_uint32 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 */ |