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Add codecs to librbcodec.
Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius <nils@rockbox.org> Tested-by: Nils Wallménius <nils@rockbox.org>
This commit is contained in:
Sean Bartell
Nils Wallménius
parent
a0009907de
commit
f40bfc9267
757 changed files with 122 additions and 122 deletions
306
lib/rbcodec/codecs/libgme/sms_apu.c
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306
lib/rbcodec/codecs/libgme/sms_apu.c
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// Sms_Snd_Emu 0.1.1. http://www.slack.net/~ant/
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#include "sms_apu.h"
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/* Copyright (C) 2003-2008 Shay Green. This module is free software; you
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can redistribute it and/or modify it under the terms of the GNU Lesser
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General Public License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version. This
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module is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details. You should have received a copy of the GNU Lesser General Public
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License along with this module; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "blargg_source.h"
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int const noise_osc = 3;
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void Sms_apu_volume( struct Sms_Apu* this, int vol )
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{
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vol = (vol - (vol*3)/20) / sms_osc_count / 64;
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Synth_volume( &this->synth, vol );
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}
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static inline int calc_output( struct Sms_Apu* this, int i )
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{
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int flags = this->ggstereo >> i;
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return (flags >> 3 & 2) | (flags & 1);
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}
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void Sms_apu_set_output( struct Sms_Apu* this, int i, struct Blip_Buffer* center, struct Blip_Buffer* left, struct Blip_Buffer* right )
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{
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#if defined(ROCKBOX)
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(void) left;
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(void) right;
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#endif
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// Must be silent (all NULL), mono (left and right NULL), or stereo (none NULL)
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require( !center || (center && !left && !right) || (center && left && right) );
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require( (unsigned) i < sms_osc_count ); // fails if you pass invalid osc index
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if ( center )
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{
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unsigned const divisor = 16384 * 16 * 2;
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this->min_tone_period = ((unsigned) Blip_clock_rate( center ) + divisor/2) / divisor;
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}
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if ( !center || !left || !right )
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{
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left = center;
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right = center;
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}
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struct Osc* o = &this->oscs [i];
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o->outputs [0] = NULL;
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o->outputs [1] = right;
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o->outputs [2] = left;
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o->outputs [3] = center;
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o->output = o->outputs [calc_output( this, i )];
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}
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static inline unsigned fibonacci_to_galois_lfsr( unsigned fibonacci, int width )
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{
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unsigned galois = 0;
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while ( --width >= 0 )
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{
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galois = (galois << 1) | (fibonacci & 1);
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fibonacci >>= 1;
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}
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return galois;
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}
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void Sms_apu_reset( struct Sms_Apu* this, unsigned feedback, int noise_width )
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{
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this->last_time = 0;
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this->latch = 0;
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this->ggstereo = 0;
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// Calculate noise feedback values
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if ( !feedback || !noise_width )
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{
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feedback = 0x0009;
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noise_width = 16;
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}
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this->looped_feedback = 1 << (noise_width - 1);
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this->noise_feedback = fibonacci_to_galois_lfsr( feedback, noise_width );
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// Reset oscs
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int i;
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for ( i = sms_osc_count; --i >= 0; )
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{
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struct Osc* o = &this->oscs [i];
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o->output = NULL;
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o->last_amp = 0;
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o->delay = 0;
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o->phase = 0;
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o->period = 0;
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o->volume = 15; // silent
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}
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this->oscs [noise_osc].phase = 0x8000;
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Sms_apu_write_ggstereo( this, 0, 0xFF );
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}
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void Sms_apu_init( struct Sms_Apu* this )
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{
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this->min_tone_period = 7;
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Synth_init( &this->synth );
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// Clear outputs to NULL FIRST
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this->ggstereo = 0;
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int i;
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for ( i = sms_osc_count; --i >= 0; )
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Sms_apu_set_output( this, i, NULL, NULL, NULL );
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Sms_apu_volume( this, (int)FP_ONE_VOLUME );
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Sms_apu_reset( this, 0, 0 );
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}
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static void run_until( struct Sms_Apu* this, blip_time_t end_time )
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{
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require( end_time >= this->last_time );
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if ( end_time <= this->last_time )
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return;
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// Synthesize each oscillator
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int idx;
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for ( idx = sms_osc_count; --idx >= 0; )
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{
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struct Osc* osc = &this->oscs [idx];
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int vol = 0;
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int amp = 0;
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// Determine what will be generated
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struct Blip_Buffer* const out = osc->output;
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if ( out )
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{
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// volumes [i] ~= 64 * pow( 1.26, 15 - i ) / pow( 1.26, 15 )
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static unsigned char const volumes [16] = {
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64, 50, 40, 32, 25, 20, 16, 13, 10, 8, 6, 5, 4, 3, 2, 0
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};
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vol = volumes [osc->volume];
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amp = (osc->phase & 1) * vol;
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// Square freq above 16 kHz yields constant amplitude at half volume
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if ( idx != noise_osc && osc->period < this->min_tone_period )
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{
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amp = vol >> 1;
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vol = 0;
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}
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// Update amplitude
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int delta = amp - osc->last_amp;
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if ( delta )
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{
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osc->last_amp = amp;
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Synth_offset( &this->synth, this->last_time, delta, out );
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Blip_set_modified( out );
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}
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}
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// Generate wave
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blip_time_t time = this->last_time + osc->delay;
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if ( time < end_time )
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{
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// Calculate actual period
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int period = osc->period;
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if ( idx == noise_osc )
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{
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period = 0x20 << (period & 3);
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if ( period == 0x100 )
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period = this->oscs [2].period * 2;
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}
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period *= 0x10;
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if ( !period )
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period = 0x10;
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// Maintain phase when silent
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int phase = osc->phase;
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if ( !vol )
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{
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int count = (end_time - time + period - 1) / period;
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time += count * period;
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if ( idx != noise_osc ) // TODO: maintain noise LFSR phase?
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phase ^= count & 1;
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}
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else
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{
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int delta = amp * 2 - vol;
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if ( idx != noise_osc )
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{
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// Square
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do
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{
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delta = -delta;
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Synth_offset( &this->synth, time, delta, out );
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time += period;
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}
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while ( time < end_time );
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phase = (delta >= 0);
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}
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else
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{
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// Noise
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unsigned const feedback = (osc->period & 4 ? this->noise_feedback : this->looped_feedback);
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do
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{
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unsigned changed = phase + 1;
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phase = ((phase & 1) * feedback) ^ (phase >> 1);
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if ( changed & 2 ) // true if bits 0 and 1 differ
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{
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delta = -delta;
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Synth_offset_inline( &this->synth, time, delta, out );
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}
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time += period;
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}
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while ( time < end_time );
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check( phase );
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}
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osc->last_amp = (phase & 1) * vol;
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Blip_set_modified( out );
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}
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osc->phase = phase;
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}
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osc->delay = time - end_time;
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}
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this->last_time = end_time;
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}
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void Sms_apu_write_ggstereo( struct Sms_Apu* this, blip_time_t time, int data )
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{
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require( (unsigned) data <= 0xFF );
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run_until( this, time );
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this->ggstereo = data;
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int i;
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for ( i = sms_osc_count; --i >= 0; )
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{
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struct Osc* osc = &this->oscs [i];
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struct Blip_Buffer* old = osc->output;
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osc->output = osc->outputs [calc_output( this, i )];
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if ( osc->output != old )
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{
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int delta = -osc->last_amp;
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if ( delta )
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{
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osc->last_amp = 0;
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if ( old )
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{
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Blip_set_modified( old );
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Synth_offset( &this->synth, this->last_time, delta, old );
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}
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}
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}
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}
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}
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void Sms_apu_write_data( struct Sms_Apu* this, blip_time_t time, int data )
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{
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require( (unsigned) data <= 0xFF );
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run_until( this, time );
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if ( data & 0x80 )
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this->latch = data;
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// We want the raw values written so our save state format can be
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// as close to hardware as possible and unspecific to any emulator.
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int idx = this->latch >> 5 & 3;
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struct Osc* osc = &this->oscs [idx];
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if ( this->latch & 0x10 )
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{
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osc->volume = data & 0x0F;
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}
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else
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{
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if ( idx == noise_osc )
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osc->phase = 0x8000; // reset noise LFSR
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// Replace high 6 bits/low 4 bits of register with data
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int lo = osc->period;
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int hi = data << 4;
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if ( idx == noise_osc || (data & 0x80) )
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{
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hi = lo;
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lo = data;
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}
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osc->period = (hi & 0x3F0) | (lo & 0x00F);
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}
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}
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void Sms_apu_end_frame( struct Sms_Apu* this, blip_time_t end_time )
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{
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if ( end_time > this->last_time )
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run_until( this, end_time );
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this->last_time -= end_time;
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assert( this->last_time >= 0 );
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}
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