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-rw-r--r--plugins/gme/game-music-emu-svn/gme/Nes_Oscs.cpp551
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diff --git a/plugins/gme/game-music-emu-svn/gme/Nes_Oscs.cpp b/plugins/gme/game-music-emu-svn/gme/Nes_Oscs.cpp
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+++ b/plugins/gme/game-music-emu-svn/gme/Nes_Oscs.cpp
@@ -0,0 +1,551 @@
+// Nes_Snd_Emu 0.1.8. http://www.slack.net/~ant/
+
+#include "Nes_Apu.h"
+
+/* Copyright (C) 2003-2006 Shay Green. This module is free software; you
+can redistribute it and/or modify it under the terms of the GNU Lesser
+General Public License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version. This
+module 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 Lesser General Public License for more
+details. You should have received a copy of the GNU Lesser General Public
+License along with this module; if not, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
+
+#include "blargg_source.h"
+
+// Nes_Osc
+
+void Nes_Osc::clock_length( int halt_mask )
+{
+ if ( length_counter && !(regs [0] & halt_mask) )
+ length_counter--;
+}
+
+void Nes_Envelope::clock_envelope()
+{
+ int period = regs [0] & 15;
+ if ( reg_written [3] ) {
+ reg_written [3] = false;
+ env_delay = period;
+ envelope = 15;
+ }
+ else if ( --env_delay < 0 ) {
+ env_delay = period;
+ if ( envelope | (regs [0] & 0x20) )
+ envelope = (envelope - 1) & 15;
+ }
+}
+
+int Nes_Envelope::volume() const
+{
+ return length_counter == 0 ? 0 : (regs [0] & 0x10) ? (regs [0] & 15) : envelope;
+}
+
+// Nes_Square
+
+void Nes_Square::clock_sweep( int negative_adjust )
+{
+ int sweep = regs [1];
+
+ if ( --sweep_delay < 0 )
+ {
+ reg_written [1] = true;
+
+ int period = this->period();
+ int shift = sweep & shift_mask;
+ if ( shift && (sweep & 0x80) && period >= 8 )
+ {
+ int offset = period >> shift;
+
+ if ( sweep & negate_flag )
+ offset = negative_adjust - offset;
+
+ if ( period + offset < 0x800 )
+ {
+ period += offset;
+ // rewrite period
+ regs [2] = period & 0xFF;
+ regs [3] = (regs [3] & ~7) | ((period >> 8) & 7);
+ }
+ }
+ }
+
+ if ( reg_written [1] ) {
+ reg_written [1] = false;
+ sweep_delay = (sweep >> 4) & 7;
+ }
+}
+
+// TODO: clean up
+inline nes_time_t Nes_Square::maintain_phase( nes_time_t time, nes_time_t end_time,
+ nes_time_t timer_period )
+{
+ nes_time_t remain = end_time - time;
+ if ( remain > 0 )
+ {
+ int count = (remain + timer_period - 1) / timer_period;
+ phase = (phase + count) & (phase_range - 1);
+ time += (blargg_long) count * timer_period;
+ }
+ return time;
+}
+
+void Nes_Square::run( nes_time_t time, nes_time_t end_time )
+{
+ const int period = this->period();
+ const int timer_period = (period + 1) * 2;
+
+ if ( !output )
+ {
+ delay = maintain_phase( time + delay, end_time, timer_period ) - end_time;
+ return;
+ }
+
+ output->set_modified();
+
+ int offset = period >> (regs [1] & shift_mask);
+ if ( regs [1] & negate_flag )
+ offset = 0;
+
+ const int volume = this->volume();
+ if ( volume == 0 || period < 8 || (period + offset) >= 0x800 )
+ {
+ if ( last_amp ) {
+ synth.offset( time, -last_amp, output );
+ last_amp = 0;
+ }
+
+ time += delay;
+ time = maintain_phase( time, end_time, timer_period );
+ }
+ else
+ {
+ // handle duty select
+ int duty_select = (regs [0] >> 6) & 3;
+ int duty = 1 << duty_select; // 1, 2, 4, 2
+ int amp = 0;
+ if ( duty_select == 3 ) {
+ duty = 2; // negated 25%
+ amp = volume;
+ }
+ if ( phase < duty )
+ amp ^= volume;
+
+ {
+ int delta = update_amp( amp );
+ if ( delta )
+ synth.offset( time, delta, output );
+ }
+
+ time += delay;
+ if ( time < end_time )
+ {
+ Blip_Buffer* const output = this->output;
+ const Synth& synth = this->synth;
+ int delta = amp * 2 - volume;
+ int phase = this->phase;
+
+ do {
+ phase = (phase + 1) & (phase_range - 1);
+ if ( phase == 0 || phase == duty ) {
+ delta = -delta;
+ synth.offset_inline( time, delta, output );
+ }
+ time += timer_period;
+ }
+ while ( time < end_time );
+
+ last_amp = (delta + volume) >> 1;
+ this->phase = phase;
+ }
+ }
+
+ delay = time - end_time;
+}
+
+// Nes_Triangle
+
+void Nes_Triangle::clock_linear_counter()
+{
+ if ( reg_written [3] )
+ linear_counter = regs [0] & 0x7F;
+ else if ( linear_counter )
+ linear_counter--;
+
+ if ( !(regs [0] & 0x80) )
+ reg_written [3] = false;
+}
+
+inline int Nes_Triangle::calc_amp() const
+{
+ int amp = phase_range - phase;
+ if ( amp < 0 )
+ amp = phase - (phase_range + 1);
+ return amp;
+}
+
+// TODO: clean up
+inline nes_time_t Nes_Triangle::maintain_phase( nes_time_t time, nes_time_t end_time,
+ nes_time_t timer_period )
+{
+ nes_time_t remain = end_time - time;
+ if ( remain > 0 )
+ {
+ int count = (remain + timer_period - 1) / timer_period;
+ phase = ((unsigned) phase + 1 - count) & (phase_range * 2 - 1);
+ phase++;
+ time += (blargg_long) count * timer_period;
+ }
+ return time;
+}
+
+void Nes_Triangle::run( nes_time_t time, nes_time_t end_time )
+{
+ const int timer_period = period() + 1;
+ if ( !output )
+ {
+ time += delay;
+ delay = 0;
+ if ( length_counter && linear_counter && timer_period >= 3 )
+ delay = maintain_phase( time, end_time, timer_period ) - end_time;
+ return;
+ }
+
+ output->set_modified();
+
+ // to do: track phase when period < 3
+ // to do: Output 7.5 on dac when period < 2? More accurate, but results in more clicks.
+
+ int delta = update_amp( calc_amp() );
+ if ( delta )
+ synth.offset( time, delta, output );
+
+ time += delay;
+ if ( length_counter == 0 || linear_counter == 0 || timer_period < 3 )
+ {
+ time = end_time;
+ }
+ else if ( time < end_time )
+ {
+ Blip_Buffer* const output = this->output;
+
+ int phase = this->phase;
+ int volume = 1;
+ if ( phase > phase_range ) {
+ phase -= phase_range;
+ volume = -volume;
+ }
+
+ do {
+ if ( --phase == 0 ) {
+ phase = phase_range;
+ volume = -volume;
+ }
+ else {
+ synth.offset_inline( time, volume, output );
+ }
+
+ time += timer_period;
+ }
+ while ( time < end_time );
+
+ if ( volume < 0 )
+ phase += phase_range;
+ this->phase = phase;
+ last_amp = calc_amp();
+ }
+ delay = time - end_time;
+}
+
+// Nes_Dmc
+
+void Nes_Dmc::reset()
+{
+ address = 0;
+ dac = 0;
+ buf = 0;
+ bits_remain = 1;
+ bits = 0;
+ buf_full = false;
+ silence = true;
+ next_irq = Nes_Apu::no_irq;
+ irq_flag = false;
+ irq_enabled = false;
+
+ Nes_Osc::reset();
+ period = 0x1AC;
+}
+
+void Nes_Dmc::recalc_irq()
+{
+ nes_time_t irq = Nes_Apu::no_irq;
+ if ( irq_enabled && length_counter )
+ irq = apu->last_dmc_time + delay +
+ ((length_counter - 1) * 8 + bits_remain - 1) * nes_time_t (period) + 1;
+ if ( irq != next_irq ) {
+ next_irq = irq;
+ apu->irq_changed();
+ }
+}
+
+int Nes_Dmc::count_reads( nes_time_t time, nes_time_t* last_read ) const
+{
+ if ( last_read )
+ *last_read = time;
+
+ if ( length_counter == 0 )
+ return 0; // not reading
+
+ nes_time_t first_read = next_read_time();
+ nes_time_t avail = time - first_read;
+ if ( avail <= 0 )
+ return 0;
+
+ int count = (avail - 1) / (period * 8) + 1;
+ if ( !(regs [0] & loop_flag) && count > length_counter )
+ count = length_counter;
+
+ if ( last_read )
+ {
+ *last_read = first_read + (count - 1) * (period * 8) + 1;
+ check( *last_read <= time );
+ check( count == count_reads( *last_read, NULL ) );
+ check( count - 1 == count_reads( *last_read - 1, NULL ) );
+ }
+
+ return count;
+}
+
+static short const dmc_period_table [2] [16] = {
+ {428, 380, 340, 320, 286, 254, 226, 214, // NTSC
+ 190, 160, 142, 128, 106, 84, 72, 54},
+
+ {398, 354, 316, 298, 276, 236, 210, 198, // PAL
+ 176, 148, 132, 118, 98, 78, 66, 50}
+};
+
+inline void Nes_Dmc::reload_sample()
+{
+ address = 0x4000 + regs [2] * 0x40;
+ length_counter = regs [3] * 0x10 + 1;
+}
+
+static byte const dac_table [128] =
+{
+ 0, 1, 2, 3, 4, 5, 6, 7, 7, 8, 9,10,11,12,13,14,
+ 15,15,16,17,18,19,20,20,21,22,23,24,24,25,26,27,
+ 27,28,29,30,31,31,32,33,33,34,35,36,36,37,38,38,
+ 39,40,41,41,42,43,43,44,45,45,46,47,47,48,48,49,
+ 50,50,51,52,52,53,53,54,55,55,56,56,57,58,58,59,
+ 59,60,60,61,61,62,63,63,64,64,65,65,66,66,67,67,
+ 68,68,69,70,70,71,71,72,72,73,73,74,74,75,75,75,
+ 76,76,77,77,78,78,79,79,80,80,81,81,82,82,82,83,
+};
+
+void Nes_Dmc::write_register( int addr, int data )
+{
+ if ( addr == 0 )
+ {
+ period = dmc_period_table [pal_mode] [data & 15];
+ irq_enabled = (data & 0xC0) == 0x80; // enabled only if loop disabled
+ irq_flag &= irq_enabled;
+ recalc_irq();
+ }
+ else if ( addr == 1 )
+ {
+ int old_dac = dac;
+ dac = data & 0x7F;
+
+ // adjust last_amp so that "pop" amplitude will be properly non-linear
+ // with respect to change in dac
+ int faked_nonlinear = dac - (dac_table [dac] - dac_table [old_dac]);
+ if ( !nonlinear )
+ last_amp = faked_nonlinear;
+ }
+}
+
+void Nes_Dmc::start()
+{
+ reload_sample();
+ fill_buffer();
+ recalc_irq();
+}
+
+void Nes_Dmc::fill_buffer()
+{
+ if ( !buf_full && length_counter )
+ {
+ require( prg_reader ); // prg_reader must be set
+ buf = prg_reader( prg_reader_data, 0x8000u + address );
+ address = (address + 1) & 0x7FFF;
+ buf_full = true;
+ if ( --length_counter == 0 )
+ {
+ if ( regs [0] & loop_flag ) {
+ reload_sample();
+ }
+ else {
+ apu->osc_enables &= ~0x10;
+ irq_flag = irq_enabled;
+ next_irq = Nes_Apu::no_irq;
+ apu->irq_changed();
+ }
+ }
+ }
+}
+
+void Nes_Dmc::run( nes_time_t time, nes_time_t end_time )
+{
+ int delta = update_amp( dac );
+ if ( !output )
+ {
+ silence = true;
+ }
+ else
+ {
+ output->set_modified();
+ if ( delta )
+ synth.offset( time, delta, output );
+ }
+
+ time += delay;
+ if ( time < end_time )
+ {
+ int bits_remain = this->bits_remain;
+ if ( silence && !buf_full )
+ {
+ int count = (end_time - time + period - 1) / period;
+ bits_remain = (bits_remain - 1 + 8 - (count % 8)) % 8 + 1;
+ time += count * period;
+ }
+ else
+ {
+ Blip_Buffer* const output = this->output;
+ const int period = this->period;
+ int bits = this->bits;
+ int dac = this->dac;
+
+ do
+ {
+ if ( !silence )
+ {
+ int step = (bits & 1) * 4 - 2;
+ bits >>= 1;
+ if ( unsigned (dac + step) <= 0x7F ) {
+ dac += step;
+ synth.offset_inline( time, step, output );
+ }
+ }
+
+ time += period;
+
+ if ( --bits_remain == 0 )
+ {
+ bits_remain = 8;
+ if ( !buf_full ) {
+ silence = true;
+ }
+ else {
+ silence = false;
+ bits = buf;
+ buf_full = false;
+ if ( !output )
+ silence = true;
+ fill_buffer();
+ }
+ }
+ }
+ while ( time < end_time );
+
+ this->dac = dac;
+ this->last_amp = dac;
+ this->bits = bits;
+ }
+ this->bits_remain = bits_remain;
+ }
+ delay = time - end_time;
+}
+
+// Nes_Noise
+
+static short const noise_period_table [16] = {
+ 0x004, 0x008, 0x010, 0x020, 0x040, 0x060, 0x080, 0x0A0,
+ 0x0CA, 0x0FE, 0x17C, 0x1FC, 0x2FA, 0x3F8, 0x7F2, 0xFE4
+};
+
+void Nes_Noise::run( nes_time_t time, nes_time_t end_time )
+{
+ int period = noise_period_table [regs [2] & 15];
+
+ if ( !output )
+ {
+ // TODO: clean up
+ time += delay;
+ delay = time + (end_time - time + period - 1) / period * period - end_time;
+ return;
+ }
+
+ output->set_modified();
+
+ const int volume = this->volume();
+ int amp = (noise & 1) ? volume : 0;
+ {
+ int delta = update_amp( amp );
+ if ( delta )
+ synth.offset( time, delta, output );
+ }
+
+ time += delay;
+ if ( time < end_time )
+ {
+ const int mode_flag = 0x80;
+
+ if ( !volume )
+ {
+ // round to next multiple of period
+ time += (end_time - time + period - 1) / period * period;
+
+ // approximate noise cycling while muted, by shuffling up noise register
+ // to do: precise muted noise cycling?
+ if ( !(regs [2] & mode_flag) ) {
+ int feedback = (noise << 13) ^ (noise << 14);
+ noise = (feedback & 0x4000) | (noise >> 1);
+ }
+ }
+ else
+ {
+ Blip_Buffer* const output = this->output;
+
+ // using resampled time avoids conversion in synth.offset()
+ blip_resampled_time_t rperiod = output->resampled_duration( period );
+ blip_resampled_time_t rtime = output->resampled_time( time );
+
+ int noise = this->noise;
+ int delta = amp * 2 - volume;
+ const int tap = (regs [2] & mode_flag ? 8 : 13);
+
+ do {
+ int feedback = (noise << tap) ^ (noise << 14);
+ time += period;
+
+ if ( (noise + 1) & 2 ) {
+ // bits 0 and 1 of noise differ
+ delta = -delta;
+ synth.offset_resampled( rtime, delta, output );
+ }
+
+ rtime += rperiod;
+ noise = (feedback & 0x4000) | (noise >> 1);
+ }
+ while ( time < end_time );
+
+ last_amp = (delta + volume) >> 1;
+ this->noise = noise;
+ }
+ }
+
+ delay = time - end_time;
+}
+
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