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Diffstat (limited to 'plugins/gme/Game_Music_Emu-0.5.2/gme/Hes_Apu.cpp')
| -rw-r--r-- | plugins/gme/Game_Music_Emu-0.5.2/gme/Hes_Apu.cpp | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/plugins/gme/Game_Music_Emu-0.5.2/gme/Hes_Apu.cpp b/plugins/gme/Game_Music_Emu-0.5.2/gme/Hes_Apu.cpp new file mode 100644 index 00000000..22389121 --- /dev/null +++ b/plugins/gme/Game_Music_Emu-0.5.2/gme/Hes_Apu.cpp @@ -0,0 +1,315 @@ +// Game_Music_Emu 0.5.2. http://www.slack.net/~ant/ + +#include "Hes_Apu.h" + +#include <string.h> + +/* Copyright (C) 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" + +bool const center_waves = true; // reduces asymmetry and clamping when starting notes + +Hes_Apu::Hes_Apu() +{ + Hes_Osc* osc = &oscs [osc_count]; + do + { + osc--; + osc->outputs [0] = 0; + osc->outputs [1] = 0; + osc->chans [0] = 0; + osc->chans [1] = 0; + osc->chans [2] = 0; + } + while ( osc != oscs ); + + reset(); +} + +void Hes_Apu::reset() +{ + latch = 0; + balance = 0xFF; + + Hes_Osc* osc = &oscs [osc_count]; + do + { + osc--; + memset( osc, 0, offsetof (Hes_Osc,outputs) ); + osc->noise_lfsr = 1; + osc->control = 0x40; + osc->balance = 0xFF; + } + while ( osc != oscs ); +} + +void Hes_Apu::osc_output( int index, Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right ) +{ + require( (unsigned) index < osc_count ); + oscs [index].chans [0] = center; + oscs [index].chans [1] = left; + oscs [index].chans [2] = right; + + Hes_Osc* osc = &oscs [osc_count]; + do + { + osc--; + balance_changed( *osc ); + } + while ( osc != oscs ); +} + +void Hes_Osc::run_until( synth_t& synth_, blip_time_t end_time ) +{ + Blip_Buffer* const osc_outputs_0 = outputs [0]; // cache often-used values + if ( osc_outputs_0 && control & 0x80 ) + { + int dac = this->dac; + + int const volume_0 = volume [0]; + { + int delta = dac * volume_0 - last_amp [0]; + if ( delta ) + synth_.offset( last_time, delta, osc_outputs_0 ); + osc_outputs_0->set_modified(); + } + + Blip_Buffer* const osc_outputs_1 = outputs [1]; + int const volume_1 = volume [1]; + if ( osc_outputs_1 ) + { + int delta = dac * volume_1 - last_amp [1]; + if ( delta ) + synth_.offset( last_time, delta, osc_outputs_1 ); + osc_outputs_1->set_modified(); + } + + blip_time_t time = last_time + delay; + if ( time < end_time ) + { + if ( noise & 0x80 ) + { + if ( volume_0 | volume_1 ) + { + // noise + int const period = (32 - (noise & 0x1F)) * 64; // TODO: correct? + unsigned noise_lfsr = this->noise_lfsr; + do + { + int new_dac = 0x1F & -(noise_lfsr >> 1 & 1); + // Implemented using "Galios configuration" + // TODO: find correct LFSR algorithm + noise_lfsr = (noise_lfsr >> 1) ^ (0xE008 & -(noise_lfsr & 1)); + //noise_lfsr = (noise_lfsr >> 1) ^ (0x6000 & -(noise_lfsr & 1)); + int delta = new_dac - dac; + if ( delta ) + { + dac = new_dac; + synth_.offset( time, delta * volume_0, osc_outputs_0 ); + if ( osc_outputs_1 ) + synth_.offset( time, delta * volume_1, osc_outputs_1 ); + } + time += period; + } + while ( time < end_time ); + + this->noise_lfsr = noise_lfsr; + assert( noise_lfsr ); + } + } + else if ( !(control & 0x40) ) + { + // wave + int phase = (this->phase + 1) & 0x1F; // pre-advance for optimal inner loop + int period = this->period * 2; + if ( period >= 14 && (volume_0 | volume_1) ) + { + do + { + int new_dac = wave [phase]; + phase = (phase + 1) & 0x1F; + int delta = new_dac - dac; + if ( delta ) + { + dac = new_dac; + synth_.offset( time, delta * volume_0, osc_outputs_0 ); + if ( osc_outputs_1 ) + synth_.offset( time, delta * volume_1, osc_outputs_1 ); + } + time += period; + } + while ( time < end_time ); + } + else + { + if ( !period ) + { + // TODO: Gekisha Boy assumes that period = 0 silences wave + //period = 0x1000 * 2; + period = 1; + //if ( !(volume_0 | volume_1) ) + // dprintf( "Used period 0\n" ); + } + + // maintain phase when silent + blargg_long count = (end_time - time + period - 1) / period; + phase += count; // phase will be masked below + time += count * period; + } + this->phase = (phase - 1) & 0x1F; // undo pre-advance + } + } + time -= end_time; + if ( time < 0 ) + time = 0; + delay = time; + + this->dac = dac; + last_amp [0] = dac * volume_0; + last_amp [1] = dac * volume_1; + } + last_time = end_time; +} + +void Hes_Apu::balance_changed( Hes_Osc& osc ) +{ + static short const log_table [32] = { // ~1.5 db per step + #define ENTRY( factor ) short (factor * Hes_Osc::amp_range / 31.0 + 0.5) + ENTRY( 0.000000 ),ENTRY( 0.005524 ),ENTRY( 0.006570 ),ENTRY( 0.007813 ), + ENTRY( 0.009291 ),ENTRY( 0.011049 ),ENTRY( 0.013139 ),ENTRY( 0.015625 ), + ENTRY( 0.018581 ),ENTRY( 0.022097 ),ENTRY( 0.026278 ),ENTRY( 0.031250 ), + ENTRY( 0.037163 ),ENTRY( 0.044194 ),ENTRY( 0.052556 ),ENTRY( 0.062500 ), + ENTRY( 0.074325 ),ENTRY( 0.088388 ),ENTRY( 0.105112 ),ENTRY( 0.125000 ), + ENTRY( 0.148651 ),ENTRY( 0.176777 ),ENTRY( 0.210224 ),ENTRY( 0.250000 ), + ENTRY( 0.297302 ),ENTRY( 0.353553 ),ENTRY( 0.420448 ),ENTRY( 0.500000 ), + ENTRY( 0.594604 ),ENTRY( 0.707107 ),ENTRY( 0.840896 ),ENTRY( 1.000000 ), + #undef ENTRY + }; + + int vol = (osc.control & 0x1F) - 0x1E * 2; + + int left = vol + (osc.balance >> 3 & 0x1E) + (balance >> 3 & 0x1E); + if ( left < 0 ) left = 0; + + int right = vol + (osc.balance << 1 & 0x1E) + (balance << 1 & 0x1E); + if ( right < 0 ) right = 0; + + left = log_table [left ]; + right = log_table [right]; + + // optimizing for the common case of being centered also allows easy + // panning using Effects_Buffer + osc.outputs [0] = osc.chans [0]; // center + osc.outputs [1] = 0; + if ( left != right ) + { + osc.outputs [0] = osc.chans [1]; // left + osc.outputs [1] = osc.chans [2]; // right + } + + if ( center_waves ) + { + osc.last_amp [0] += (left - osc.volume [0]) * 16; + osc.last_amp [1] += (right - osc.volume [1]) * 16; + } + + osc.volume [0] = left; + osc.volume [1] = right; +} + +void Hes_Apu::write_data( blip_time_t time, int addr, int data ) +{ + if ( addr == 0x800 ) + { + latch = data & 7; + } + else if ( addr == 0x801 ) + { + if ( balance != data ) + { + balance = data; + + Hes_Osc* osc = &oscs [osc_count]; + do + { + osc--; + osc->run_until( synth, time ); + balance_changed( *oscs ); + } + while ( osc != oscs ); + } + } + else if ( latch < osc_count ) + { + Hes_Osc& osc = oscs [latch]; + osc.run_until( synth, time ); + switch ( addr ) + { + case 0x802: + osc.period = (osc.period & 0xF00) | data; + break; + + case 0x803: + osc.period = (osc.period & 0x0FF) | ((data & 0x0F) << 8); + break; + + case 0x804: + if ( osc.control & 0x40 & ~data ) + osc.phase = 0; + osc.control = data; + balance_changed( osc ); + break; + + case 0x805: + osc.balance = data; + balance_changed( osc ); + break; + + case 0x806: + data &= 0x1F; + if ( !(osc.control & 0x40) ) + { + osc.wave [osc.phase] = data; + osc.phase = (osc.phase + 1) & 0x1F; + } + else if ( osc.control & 0x80 ) + { + osc.dac = data; + } + break; + + case 0x807: + if ( &osc >= &oscs [4] ) + osc.noise = data; + break; + + case 0x809: + if ( !(data & 0x80) && (data & 0x03) != 0 ) + dprintf( "HES LFO not supported\n" ); + } + } +} + +void Hes_Apu::end_frame( blip_time_t end_time ) +{ + Hes_Osc* osc = &oscs [osc_count]; + do + { + osc--; + if ( end_time > osc->last_time ) + osc->run_until( synth, end_time ); + assert( osc->last_time >= end_time ); + osc->last_time -= end_time; + } + while ( osc != oscs ); +} |