diff options
Diffstat (limited to 'plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Oscs.cpp')
-rw-r--r-- | plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Oscs.cpp | 551 |
1 files changed, 551 insertions, 0 deletions
diff --git a/plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Oscs.cpp b/plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Oscs.cpp new file mode 100644 index 00000000..1ad3f59c --- /dev/null +++ b/plugins/gme/Game_Music_Emu-0.5.2/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; +} + |