wmwavegen.c

WM9713 audio codec driver for WinCE 5.0

/*-----------------------------------------------------------------------------
 * Copyright (c) Wolfson Microelectronics plc.  All rights reserved.
 *
 * This software as well as any related documentation is furnished under 
 * license and may only be used or copied in accordance with the terms of the 
 * license. The information in this file is furnished for informational use 
 * only, is subject to change without notice, and should not be construed as 
 * a commitment by Wolfson Microelectronics plc. Wolfson Microelectronics plc
 * assumes no responsibility or liability for any errors or inaccuracies that
 * may appear in this document or any software that may be provided in
 * association with this document. 
 *
 * Except as permitted by such license, no part of this document may be 
 * reproduced, stored in a retrieval system, or transmitted in any form or by 
 * any means without the express written consent of Wolfson Microelectronics plc. 
 *
 * $Id: WMWaveGen.c 2505 2005-11-30 17:30:38Z ian $
 *
 * Functions for generating different sound waveforms.
 *
 * Warning:
 *  This driver is specifically written for Wolfson Codecs. It is not a 
 *  general CODEC device driver.
 *
 * -----------------------------------------------------------------------------*/

/*
 * Include files
 */
#include <stdlib.h>
#include "WMCommon.h"
#include "WMWaveGen.h"

/*
 * Global definitions
 */
typedef struct tagWaveTable
{
    int         nyquistDivisor;
    const short *waveData;
} WaveTable;

#define AMPLITUDE_DIVISOR   32768

#if WM_TESTING
/*
 * Function prototypes
 */
void private_GenerateWave(WM_AUDIO_STEREO_SAMPLE   *buffer,
                          int               nSamples,
                          int               sampleRate,
                          unsigned short    frequency,
                          unsigned short    amplitude,
                          WM_WAVEGEN_FORMAT format,
                          WM_WAVEGEN_CTX    *pRestart,
                          const WaveTable   *waveTable
                          );

/*
 * Wave tables for a square wave, synthesised using the following formula:
 *
 *    y = sin(1*x)/1 + sin(3*x)/3 + sin (5*x)/5 + ...
 *
 * The tables give increasingly better approximations to the square wave
 * by including more of the partials, however the higher order tables can
 * only be used if Nyquist allows.  The maximum frequency for the different
 * tables at 44.1kHz is:
 *
 * Table    frequency       formula
 *   1        22050Hz    sample_rate/2
 *   2         7350Hz    sample_rate/6
 *   3         4410Hz    sample_rate/10
 *   4         3150Hz    sample_rate/14
 *   5         2450Hz    sample_rate/18
 *   6         2004Hz    sample_rate/22
 *   7         1696Hz    sample_rate/26
 *   8         1470Hz    sample_rate/30
 *   9         1297Hz    sample_rate/34
 *  10         1160Hz    sample_rate/38
 * 
 *
 * The samples have been scaled to all give -32767 to 32767 peak-to-peak
 */

/*
 * 1st partial - i.e. just sine wave.
 *
 * y = sin(x)
 *
 * Nyquist divisor 2 => max frequency 22050Hz at 44.1kHz
 * However, we will use this even if we're above the Nyquist limit
 * because there isn't anything better.
 */
static const short SquareWave1[] =
{
         0,   1608,   3212,   4808,   6393,   7962,   9512,  11039,
     12539,  14010,  15446,  16846,  18204,  19519,  20787,  22005,
     23170,  24279,  25329,  26319,  27245,  28105,  28898,  29621,
     30273,  30852,  31356,  31785,  32137,  32412,  32609,  32728,
     32767,  32728,  32609,  32412,  32137,  31785,  31356,  30852,
     30273,  29621,  28898,  28105,  27245,  26319,  25329,  24279,
     23170,  22005,  20787,  19519,  18204,  16846,  15446,  14010,
     12539,  11039,  9512,    7962,   6393,   4808,   3212,   1608,
         0,  -1608,  -3212,  -4808,  -6393,  -7962,  -9512, -11039,
    -12539, -14010, -15446, -16846, -18204, -19519, -20787, -22005,
    -23170, -24279, -25329, -26319, -27245, -28105, -28898, -29621,
    -30273, -30852, -31356, -31785, -32137, -32412, -32609, -32728,
    -32767, -32728, -32609, -32412, -32137, -31785, -31356, -30852,
    -30273, -29621, -28898, -28105, -27245, -26319, -25329, -24279,
    -23170, -22005, -20787, -19519, -18204, -16846, -15446, -14010,
    -12539, -11039,  -9512,  -7962,  -6393,  -4808,  -3212,  -1608,
         0
};

/*
 * 2nd partial
 *
 * y = sin(x) + sin(3x)/3
 *
 * Nyquist divisor 6 => max frequency 7350Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL2
static const short SquareWave2[] =
{
         0,   3405,   6769,  10053,  13217,  16225,  19044,  21645,
     24003,  26097,  27912,  29438,  30671,  31611,  32265,  32645,
     32767,  32653,  32327,  31818,  31158,  30379,  29515,  28603,
     27676,  26767,  25909,  25129,  24454,  23906,  23501,  23253,
     23170,  23253,  23501,  23906,  24454,  25129,  25909,  26767,
     27676,  28603,  29515,  30379,  31158,  31818,  32327,  32653,
     32767,  32645,  32265,  31611,  30671,  29438,  27912,  26097,
     24003,  21645,  19044,  16225,  13217,  10053,   6769,   3405,
         0,  -3405,  -6769, -10053, -13217, -16225, -19044, -21645,
    -24003, -26097, -27912, -29438, -30671, -31611, -32265, -32645,
    -32767, -32653, -32327, -31818, -31158, -30379, -29515, -28603,
    -27676, -26767, -25909, -25129, -24454, -23906, -23501, -23253,
    -23170, -23253, -23501, -23906, -24454, -25129, -25909, -26767,
    -27676, -28603, -29515, -30379, -31158, -31818, -32327, -32653,
    -32767, -32645, -32265, -31611, -30671, -29438, -27912, -26097,
    -24003, -21645, -19044, -16225, -13217, -10053,  -6769,  -3405,
         0
};
#endif

/*
 * 3rd partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5
 *
 * Nyquist divisor 10 => max frequency 4410Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL3
static const short SquareWave3[] =
{
         0,   5150,  10157,  14883,  19205,  23020,  26247,  28835,
     30760,  32029,  32678,  32767,  32379,  31614,  30580,  29391,
     28158,  26984,  25958,  25149,  24608,  24360,  24408,  24731,
     25291,  26031,  26883,  27773,  28628,  29376,  29958,  30326,
     30452,  30326,  29958,  29376,  28628,  27773,  26883,  26031,
     25291,  24731,  24408,  24360,  24608,  25149,  25958,  26984,
     28158,  29391,  30580,  31614,  32379,  32767,  32678,  32029,
     30760,  28835,  26247,  23020,  19205,  14883,  10157,   5150,
         0,  -5150, -10157, -14883, -19205, -23020, -26247, -28835,
    -30760, -32029, -32678, -32767, -32379, -31614, -30580, -29391,
    -28158, -26984, -25958, -25149, -24608, -24360, -24408, -24731,
    -25291, -26031, -26883, -27773, -28628, -29376, -29958, -30326,
    -30452, -30326, -29958, -29376, -28628, -27773, -26883, -26031,
    -25291, -24731, -24408, -24360, -24608, -25149, -25958, -26984,
    -28158, -29391, -30580, -31614, -32379, -32767, -32678, -32029,
    -30760, -28835, -26247, -23020, -19205, -14883, -10157,  -5150,
         0
};
#endif

/*
 * 4th partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5 + sin(7x)/7
 *
 * Nyquist divisor 14 => max frequency 3150Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL4
static const short SquareWave4[] =
{
         0,   6859,  13376,  19239,  24192,  28059,  30755,  32291,
     32767,  32361,  31303,  29856,  28280,  26816,  25652,  24919,
     24674,  24904,  25533,  26439,  27469,  28467,  29289,  29824,
     30008,  29829,  29326,  28585,  27722,  26866,  26146,  25668,
     25500,  25668,  26146,  26866,  27722,  28585,  29326,  29829,
     30008,  29824,  29289,  28467,  27469,  26439,  25533,  24904,
     24674,  24919,  25652,  26816,  28280,  29856,  31303,  32361,
     32767,  32291,  30755,  28059,  24192,  19239,  13376,   6859,
         0,  -6859, -13376, -19239, -24192, -28059, -30755, -32291,
    -32767, -32361, -31303, -29856, -28280, -26816, -25652, -24919,
    -24674, -24904, -25533, -26439, -27469, -28467, -29289, -29824,
    -30008, -29829, -29326, -28585, -27722, -26866, -26146, -25668,
    -25500, -25668, -26146, -26866, -27722, -28585, -29326, -29829,
    -30008, -29824, -29289, -28467, -27469, -26439, -25533, -24904,
    -24674, -24919, -25652, -26816, -28280, -29856, -31303, -32361,
    -32767, -32291, -30755, -28059, -24192, -19239, -13376,  -6859,
         0
};
#endif

/*
 * 5th partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5 + sin(7x)/7 + sin(9x)/9
 *
 * Nyquist divisor 18 => max frequency 2450Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL5
static const short SquareWave5[] =
{
         0,   8577,  16486,  23154,  28174,  31363,  32767,  32649,
     31429,  29611,  27698,  26116,  25154,  24930,  25398,  26372,
     27582,  28736,  29579,  29948,  29795,  29190,  28296,  27334,
     26526,  26051,  26006,  26388,  27096,  27959,  28776,  29355,
     29565,  29355,  28776,  27959,  27096,  26388,  26006,  26051,
     26526,  27334,  28296,  29190,  29795,  29948,  29579,  28736,
     27582,  26372,  25398,  24930,  25154,  26116,  27698,  29611,
     31429,  32649,  32767,  31363,  28174,  23154,  16486,   8577,
         0,  -8577, -16486, -23154, -28174, -31363, -32767, -32649,
    -31429, -29611, -27698, -26116, -25154, -24930, -25398, -26372,
    -27582, -28736, -29579, -29948, -29795, -29190, -28296, -27334,
    -26526, -26051, -26006, -26388, -27096, -27959, -28776, -29355,
    -29565, -29355, -28776, -27959, -27096, -26388, -26006, -26051,
    -26526, -27334, -28296, -29190, -29795, -29948, -29579, -28736,
    -27582, -26372, -25398, -24930, -25154, -26116, -27698, -29611,
    -31429, -32649, -32767, -31363, -28174, -23154, -16486,  -8577,
         0
};
#endif

/*
 * 6th partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5 + sin(7x)/7 + sin(9x)/9 + sin(11x)/11
 *
 * Nyquist divisor 22 => max frequency 2004Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL6
static const short SquareWave6[] =
{
         0,  10240,  19342,  26392,  30877,  32767,  32479,  30758,
     28479,  26449,  25231,  25053,  25804,  27115,  28503,  29520,
     29884,  29543,  28669,  27587,  26661,  26181,  26276,  26885,
     27782,  28661,  29235,  29323,  28909,  28142,  27282,  26617,
     26368,  26617,  27282,  28142,  28909,  29323,  29235,  28661,
     27782,  26885,  26276,  26181,  26661,  27587,  28669,  29543,
     29884,  29520,  28503,  27115,  25804,  25053,  25231,  26449,
     28479,  30758,  32479,  32767,  30877,  26392,  19342,  10240,
         0, -10240, -19342, -26392, -30877, -32767, -32479, -30758,
    -28479, -26449, -25231, -25053, -25804, -27115, -28503, -29520,
    -29884, -29543, -28669, -27587, -26661, -26181, -26276, -26885,
    -27782, -28661, -29235, -29323, -28909, -28142, -27282, -26617,
    -26368, -26617, -27282, -28142, -28909, -29323, -29235, -28661,
    -27782, -26885, -26276, -26181, -26661, -27587, -28669, -29543,
    -29884, -29520, -28503, -27115, -25804, -25053, -25231, -26449,
    -28479, -30758, -32479, -32767, -30877, -26392, -19342, -10240,
         0
};
#endif

/*
 * 7th partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5 + sin(7x)/7 + sin(9x)/9 + sin(11x)/11
 *     + sin(13x)/13
 *
 * Nyquist divisor 26 => max frequency 1696Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL7
static const short SquareWave7[] =
{
         0,  11913,  22040,  29077,  32525,  32767,  30876,  28228,
     26067,  25150,  25603,  26994,  28594,  29701,  29910,  29239,
     28071,  26956,  26372,  26530,  27304,  28317,  29108,  29343,
     28943,  28114,  27239,  26709,  26751,  27335,  28188,  28925,
     29213,  28925,  28188,  27335,  26751,  26709,  27239,  28114,
     28943,  29343,  29108,  28317,  27304,  26530,  26372,  26956,
     28071,  29239,  29910,  29701,  28594,  26994,  25603,  25150,
     26067,  28228,  30876,  32767,  32525,  29077,  22040,  11913,
         0, -11913, -22040, -29077, -32525, -32767, -30876, -28228,
    -26067, -25150, -25603, -26994, -28594, -29701, -29910, -29239,
    -28071, -26956, -26372, -26530, -27304, -28317, -29108, -29343,
    -28943, -28114, -27239, -26709, -26751, -27335, -28188, -28925,
    -29213, -28925, -28188, -27335, -26751, -26709, -27239, -28114,
    -28943, -29343, -29108, -28317, -27304, -26530, -26372, -26956,
    -28071, -29239, -29910, -29701, -28594, -26994, -25603, -25150,
    -26067, -28228, -30876, -32767, -32525, -29077, -22040, -11913,
         0
};
#endif

/*
 * 8th partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5 + sin(7x)/7 + sin(9x)/9 + sin(11x)/11
 *     + sin(13x)/13 + sin(15x)/15
 *
 * Nyquist divisor 30 => max frequency 1470Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL8
static const short SquareWave8[] =
{
         0,  13416,  24238,  30775,  32767,  31336,  28414,  25909,
     24991,  25776,  27510,  29100,  29712,  29156,  27888,  26690,
     26217,  26660,  27691,  28683,  29081,  28700,  27803,  26928,
     26572,  26918,  27741,  28551,  28884,  28556,  27769,  26985,
     26662,  26985,  27769,  28556,  28884,  28551,  27741,  26918,
     26572,  26928,  27803,  28700,  29081,  28683,  27691,  26660,
     26217,  26690,  27888,  29156,  29712,  29100,  27510,  25776,
     24991,  25909,  28414,  31336,  32767,  30775,  24238,  13416,
         0, -13416, -24238, -30775, -32767, -31336, -28414, -25909,
    -24991, -25776, -27510, -29100, -29712, -29156, -27888, -26690,
    -26217, -26660, -27691, -28683, -29081, -28700, -27803, -26928,
    -26572, -26918, -27741, -28551, -28884, -28556, -27769, -26985,
    -26662, -26985, -27769, -28556, -28884, -28551, -27741, -26918,
    -26572, -26928, -27803, -28700, -29081, -28683, -27691, -26660,
    -26217, -26690, -27888, -29156, -29712, -29100, -27510, -25776,
    -24991, -25909, -28414, -31336, -32767, -30775, -24238, -13416,
         0,
};
#endif

/*
 * 9th partial
 *
 * y = sin(x) + sin(3x)/3 + sin(5x)/5 + sin(7x)/7 + sin(9x)/9 + sin(11x)/11
 *     + sin(13x)/13 + sin(15x)/15 + sin(17x)/17
 *
 * Nyquist divisor 34 => max frequency 1297Hz at 44.1kHz
 */
#if WM_SQUAREWAVE_PARTIAL9
static const short SquareWave9[] =
{
         0,  15144,  26637,  32415,  32767,  29923,  26756,  25334,
     26110,  28081,  29712,  29976,  28915,  27439,  26610,  26921,
     28034,  29097,  29374,  28734,  27695,  27017,  27159,  27974,
     28851,  29159,  28699,  27827,  27181,  27223,  27910,  28737,
     29101,  28737,  27910,  27223,  27181,  27827,  28699,  29159,
     28851,  27974,  27159,  27017,  27695,  28734,  29374,  29097,
     28034,  26921,  26610,  27439,  28915,  29976,  29712,  28081,
     26110,  25334,  26756,  29923,  32767,  32415,  26637,  15144,
         0, -15144, -26637, -32415, -32767, -29923, -26756, -25334,
    -26110, -28081, -29712, -29976, -28915, -27439, -26610, -26921,
    -28034, -29097, -29374, -28734, -27695, -27017, -27159, -27974,
    -28851, -29159, -28699, -27827, -27181, -27223, -27910, -28737,
    -29101, -28737, -27910, -27223, -27181, -27827, -28699, -29159,
    -28851, -27974, -27159, -27017, -27695, -28734, -29374, -29097,
    -28034, -26921, -26610, -27439, -28915, -29976, -29712, -28081,
    -26110, -25334, -26756, -29923, -32767, -32415, -26637, -15144,