ceab0b04eb
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27208 a1c6a512-1295-4272-9138-f99709370657
152 lines
4.3 KiB
C
152 lines
4.3 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Pacbox - a Pacman Emulator for Rockbox
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*
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* Based on PIE - Pacman Instructional Emulator
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*
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* Namco custom waveform sound generator 3 (Pacman hardware)
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*
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* Copyright (c) 2003,2004 Alessandro Scotti
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* http://www.ascotti.org/
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "plugin.h"
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#include "wsg3.h"
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struct wsg3 wsg3;
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static bool wsg3_get_voice(struct wsg3_voice *voice, int index)
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{
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int base = 5*index;
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const unsigned char *regs = wsg3.sound_regs;
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unsigned x;
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x = regs[0x15 + base] & 0x0F;
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if (x == 0)
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return false;
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voice->volume = x;
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x = (regs[0x14 + base] & 0x0F);
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x = (x << 4) | (regs[0x13 + base] & 0x0F);
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x = (x << 4) | (regs[0x12 + base] & 0x0F);
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x = (x << 4) | (regs[0x11 + base] & 0x0F);
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x = (x << 4);
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if (index == 0)
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{
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/* The first voice has an extra 4-bit of data */
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x |= regs[0x10 + base] & 0x0F;
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}
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if (x == 0)
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return false;
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voice->frequency = x;
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voice->waveform = regs[0x05 + base] & 0x07;
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return true;
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}
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void wsg3_play_sound(int16_t * buf, int len)
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{
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struct wsg3_voice voice;
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if (wsg3_get_voice(&voice, 0))
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{
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unsigned offset = wsg3.wave_offset[0];
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unsigned step = voice.frequency * wsg3.resample_step;
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int16_t * wave_data = wsg3.sound_wave_data + 32 * voice.waveform;
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int volume = voice.volume;
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int i;
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for (i = 0; i < len; i++)
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{
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/* Should be shifted right by 15, but we must also get rid
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* of the 10 bits used for decimals */
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buf[i] = (int)wave_data[(offset >> 25) & 0x1F] * volume;
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offset += step;
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}
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wsg3.wave_offset[0] = offset;
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}
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if (wsg3_get_voice(&voice, 1))
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{
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unsigned offset = wsg3.wave_offset[1];
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unsigned step = voice.frequency * wsg3.resample_step;
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int16_t * wave_data = wsg3.sound_wave_data + 32 * voice.waveform;
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int volume = voice.volume;
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int i;
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for (i = 0; i < len; i++)
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{
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/* Should be shifted right by 15, but we must also get rid
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* of the 10 bits used for decimals */
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buf[i] += (int)wave_data[(offset >> 25) & 0x1F] * volume;
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offset += step;
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}
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wsg3.wave_offset[1] = offset;
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}
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if (wsg3_get_voice(&voice, 2))
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{
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unsigned offset = wsg3.wave_offset[2];
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unsigned step = voice.frequency * wsg3.resample_step;
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int16_t * wave_data = wsg3.sound_wave_data + 32 * voice.waveform;
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int volume = voice.volume;
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int i;
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for (i = 0; i < len; i++)
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{
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/* Should be shifted right by 15, but we must also get rid
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* of the 10 bits used for decimals */
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buf[i] += (int)wave_data[(offset >> 25) & 0x1F] * volume;
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offset += step;
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}
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wsg3.wave_offset[2] = offset;
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}
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}
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void wsg3_set_sampling_rate(unsigned sampling_rate)
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{
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wsg3.sampling_rate = sampling_rate;
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wsg3.resample_step = (wsg3.master_clock << 10) / sampling_rate;
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}
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void wsg3_set_sound_prom( const unsigned char * prom )
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{
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int i;
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memcpy(wsg3.sound_prom, prom, 32*8);
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/* Copy wave data and convert 4-bit unsigned -> 16-bit signed,
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* prenormalized */
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for (i = 0; i < 32*8; i++)
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wsg3.sound_wave_data[i] = ((int16_t)wsg3.sound_prom[i] - 8) * 85;
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}
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void wsg3_init(unsigned master_clock)
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{
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memset(&wsg3, 0, sizeof (struct wsg3));
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wsg3.master_clock = master_clock;
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}
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