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/math.h | |
| parent | 35303ae975a5b1bdecc2492bc96e2b8e89b62a3d (diff) | |
runtime: converting runtime core to gr namespace, gnuradio include dir.
Diffstat (limited to 'gnuradio-runtime/include/gnuradio/math.h')
| -rw-r--r-- | gnuradio-runtime/include/gnuradio/math.h | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/gnuradio-runtime/include/gnuradio/math.h b/gnuradio-runtime/include/gnuradio/math.h new file mode 100644 index 0000000000..ec4cfb014f --- /dev/null +++ b/gnuradio-runtime/include/gnuradio/math.h @@ -0,0 +1,226 @@ +/* -*- c++ -*- */ +/* + * Copyright 2003,2005,2008,2013 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. + */ + +/* + * mathematical odds and ends. + */ + +#ifndef _GR_MATH_H_ +#define _GR_MATH_H_ + +#include <gnuradio/api.h> +#include <gnuradio/gr_complex.h> + +namespace gr { + + static inline bool + is_power_of_2(long x) + { + return x != 0 && (x & (x-1)) == 0; + } + + /*! + * \brief Fast arc tangent using table lookup and linear interpolation + * \ingroup misc + * + * \param y component of input vector + * \param x component of input vector + * \returns float angle angle of vector (x, y) in radians + * + * This function calculates the angle of the vector (x,y) based on a + * table lookup and linear interpolation. The table uses a 256 point + * table covering -45 to +45 degrees and uses symetry to determine + * the final angle value in the range of -180 to 180 degrees. Note + * that this function uses the small angle approximation for values + * close to zero. This routine calculates the arc tangent with an + * average error of +/- 0.045 degrees. + */ + GR_RUNTIME_API float fast_atan2f(float y, float x); + + static inline float + fast_atan2f(gr_complex z) + { + return fast_atan2f(z.imag(), z.real()); + } + + /* This bounds x by +/- clip without a branch */ + static inline float + branchless_clip(float x, float clip) + { + float x1 = fabsf(x+clip); + float x2 = fabsf(x-clip); + x1 -= x2; + return 0.5*x1; + } + + static inline float + clip(float x, float clip) + { + float y = x; + if(x > clip) + y = clip; + else if(x < -clip) + y = -clip; + return y; + } + + // Slicer Functions + static inline unsigned int + binary_slicer(float x) + { + if(x >= 0) + return 1; + else + return 0; + } + + static inline unsigned int + quad_45deg_slicer(float r, float i) + { + unsigned int ret = 0; + if((r >= 0) && (i >= 0)) + ret = 0; + else if((r < 0) && (i >= 0)) + ret = 1; + else if((r < 0) && (i < 0)) + ret = 2; + else + ret = 3; + return ret; + } + + static inline unsigned int + quad_0deg_slicer(float r, float i) + { + unsigned int ret = 0; + if(fabsf(r) > fabsf(i)) { + if(r > 0) + ret = 0; + else + ret = 2; + } + else { + if(i > 0) + ret = 1; + else + ret = 3; + } + + return ret; + } + + static inline unsigned int + quad_45deg_slicer(gr_complex x) + { + return quad_45deg_slicer(x.real(), x.imag()); + } + + static inline unsigned int + quad_0deg_slicer(gr_complex x) + { + return quad_0deg_slicer(x.real(), x.imag()); + } + + // Branchless Slicer Functions + static inline unsigned int + branchless_binary_slicer(float x) + { + return (x >= 0); + } + + static inline unsigned int + branchless_quad_0deg_slicer(float r, float i) + { + unsigned int ret = 0; + ret = (fabsf(r) > fabsf(i)) * (((r < 0) << 0x1)); // either 0 (00) or 2 (10) + ret |= (fabsf(i) > fabsf(r)) * (((i < 0) << 0x1) | 0x1); // either 1 (01) or 3 (11) + + return ret; + } + + static inline unsigned int + branchless_quad_0deg_slicer(gr_complex x) + { + return branchless_quad_0deg_slicer(x.real(), x.imag()); + } + + static inline unsigned int + branchless_quad_45deg_slicer(float r, float i) + { + char ret = (r <= 0); + ret |= ((i <= 0) << 1); + return (ret ^ ((ret & 0x2) >> 0x1)); + } + + static inline unsigned int + branchless_quad_45deg_slicer(gr_complex x) + { + return branchless_quad_45deg_slicer(x.real(), x.imag()); + } + + /*! + * \param x any value + * \param pow2 must be a power of 2 + * \returns \p x rounded down to a multiple of \p pow2. + */ + static inline size_t + p2_round_down(size_t x, size_t pow2) + { + return x & -pow2; + } + + /*! + * \param x any value + * \param pow2 must be a power of 2 + * \returns \p x rounded up to a multiple of \p pow2. + */ + static inline size_t + p2_round_up(size_t x, size_t pow2) + { + return p2_round_down(x + pow2 - 1, pow2); + } + + /*! + * \param x any value + * \param pow2 must be a power of 2 + * \returns \p x modulo \p pow2. + */ + static inline size_t + p2_modulo(size_t x, size_t pow2) + { + return x & (pow2 - 1); + } + + /*! + * \param x any value + * \param pow2 must be a power of 2 + * \returns \p pow2 - (\p x modulo \p pow2). + */ + static inline size_t + p2_modulo_neg(size_t x, size_t pow2) + { + return pow2 - p2_modulo(x, pow2); + } + +} /* namespace gr */ + +#endif /* _GR_MATH_H_ */ |