spandsp: math_fixed.h Source File

spandsp 0.0.6

math_fixed.h
1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * math_fixed.h
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2010 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26#if !defined(_MATH_FIXED_H_)
27#define _MATH_FIXED_H_
28
29/*! \page math_fixed_page Fixed point math functions
30
31\section math_fixed_page_sec_1 What does it do?
32
33\section math_fixed_page_sec_2 How does it work?
34*/
35
36#if defined(__cplusplus)
37extern "C"
38{
39#endif
40
41#if defined(SPANDSP_USE_FIXED_POINT)
42SPAN_DECLARE(uint16_t) sqrtu32_u16(uint32_t x);
43#endif
44
45SPAN_DECLARE(uint16_t) fixed_reciprocal16(uint16_t x, int *shift);
46
47SPAN_DECLARE(uint16_t) fixed_divide16(uint16_t y, uint16_t x);
48
49SPAN_DECLARE(uint16_t) fixed_divide32(uint32_t y, uint16_t x);
50
51SPAN_DECLARE(int16_t) fixed_log10_16(uint16_t x);
52
53SPAN_DECLARE(int32_t) fixed_log10_32(uint32_t x);
54
55SPAN_DECLARE(uint16_t) fixed_sqrt16(uint16_t x);
56
57SPAN_DECLARE(uint16_t) fixed_sqrt32(uint32_t x);
58
59/*! Evaluate an approximate 16 bit fixed point sine.
60 \brief Evaluate an approximate 16 bit fixed point sine.
61 \param x A 16 bit unsigned angle, in 360/65536 degree steps.
62 \return sin(x)*32767. */
63SPAN_DECLARE(int16_t) fixed_sin(uint16_t x);
64
65/*! Evaluate an approximate 16 bit fixed point cosine.
66 \brief Evaluate an approximate 16 bit fixed point cosine.
67 \param x A 16 bit unsigned angle, in 360/65536 degree steps.
68 \return cos(x)*32767. */
69SPAN_DECLARE(int16_t) fixed_cos(uint16_t x);
70
71/*! Evaluate an approximate 16 bit fixed point sine.
72 \brief Evaluate an approximate 16 bit fixed point sine.
73 \param y .
74 \param x .
75 \return The 16 bit unsigned angle, in 360/65536 degree steps. */
76SPAN_DECLARE(uint16_t) fixed_atan2(int16_t y, int16_t x);
77
78#if defined(__cplusplus)
79}
80#endif
81
82#endif
83/*- End of file ------------------------------------------------------------*/
fixed_cos
int16_t fixed_cos(uint16_t x)
Evaluate an approximate 16 bit fixed point cosine.
Definition math_fixed.c:188
fixed_sin
int16_t fixed_sin(uint16_t x)
Evaluate an approximate 16 bit fixed point sine.
Definition math_fixed.c:163
fixed_atan2
uint16_t fixed_atan2(int16_t y, int16_t x)
Evaluate an approximate 16 bit fixed point sine.
Definition math_fixed.c:214