From f40bfc9267b13b54e6379dfe7539447662879d24 Mon Sep 17 00:00:00 2001 From: Sean Bartell Date: Sat, 25 Jun 2011 21:32:25 -0400 Subject: Add codecs to librbcodec. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius Tested-by: Nils Wallménius --- lib/rbcodec/codecs/libgme/nes_fme7_apu.c | 136 +++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 lib/rbcodec/codecs/libgme/nes_fme7_apu.c (limited to 'lib/rbcodec/codecs/libgme/nes_fme7_apu.c') diff --git a/lib/rbcodec/codecs/libgme/nes_fme7_apu.c b/lib/rbcodec/codecs/libgme/nes_fme7_apu.c new file mode 100644 index 0000000000..3e47e0b17c --- /dev/null +++ b/lib/rbcodec/codecs/libgme/nes_fme7_apu.c @@ -0,0 +1,136 @@ +// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/ + +#include "nes_fme7_apu.h" + +#include + +/* 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" + +void Fme7_init( struct Nes_Fme7_Apu* this ) +{ + Synth_init( &this->synth ); + + Fme7_output( this, NULL ); + Fme7_volume( this, (int)FP_ONE_VOLUME ); + Fme7_reset( this ); +} + +void Fme7_reset( struct Nes_Fme7_Apu* this ) +{ + this->last_time = 0; + + int i; + for ( i = 0; i < fme7_osc_count; i++ ) + this->oscs [i].last_amp = 0; + + this->latch = 0; + memset( this->regs, 0, sizeof this->regs); + memset( this->phases, 0, sizeof this->phases ); + memset( this->delays, 0, sizeof this->delays ); +} + +static unsigned char const amp_table [16] = +{ + #define ENTRY( n ) (unsigned char) (n * amp_range + 0.5) + ENTRY(0.0000), ENTRY(0.0078), ENTRY(0.0110), ENTRY(0.0156), + ENTRY(0.0221), ENTRY(0.0312), ENTRY(0.0441), ENTRY(0.0624), + ENTRY(0.0883), ENTRY(0.1249), ENTRY(0.1766), ENTRY(0.2498), + ENTRY(0.3534), ENTRY(0.4998), ENTRY(0.7070), ENTRY(1.0000) + #undef ENTRY +}; + +void Fme7_run_until( struct Nes_Fme7_Apu* this, blip_time_t end_time ) +{ + require( end_time >= this->last_time ); + + int index; + for ( index = 0; index < fme7_osc_count; index++ ) + { + int mode = this->regs [7] >> index; + int vol_mode = this->regs [010 + index]; + int volume = amp_table [vol_mode & 0x0F]; + + struct Blip_Buffer* const osc_output = this->oscs [index].output; + if ( !osc_output ) + continue; + + // check for unsupported mode + #ifndef NDEBUG + if ( (mode & 011) <= 001 && vol_mode & 0x1F ) + debug_printf( "FME7 used unimplemented sound mode: %02X, vol_mode: %02X\n", + mode, vol_mode & 0x1F ); + #endif + + if ( (mode & 001) | (vol_mode & 0x10) ) + volume = 0; // noise and envelope aren't supported + + // period + int const period_factor = 16; + unsigned period = (this->regs [index * 2 + 1] & 0x0F) * 0x100 * period_factor + + this->regs [index * 2] * period_factor; + if ( period < 50 ) // around 22 kHz + { + volume = 0; + if ( !period ) // on my AY-3-8910A, period doesn't have extra one added + period = period_factor; + } + + // current amplitude + int amp = volume; + if ( !this->phases [index] ) + amp = 0; + + { + int delta = amp - this->oscs [index].last_amp; + if ( delta ) + { + this->oscs [index].last_amp = amp; + Blip_set_modified( osc_output ); + Synth_offset( &this->synth, this->last_time, delta, osc_output ); + } + } + + blip_time_t time = this->last_time + this->delays [index]; + if ( time < end_time ) + { + int delta = amp * 2 - volume; + Blip_set_modified( osc_output ); + if ( volume ) + { + do + { + delta = -delta; + Synth_offset_inline( &this->synth, time, delta, osc_output ); + time += period; + } + while ( time < end_time ); + + this->oscs [index].last_amp = (delta + volume) >> 1; + this->phases [index] = (delta > 0); + } + else + { + // maintain phase when silent + int count = (end_time - time + period - 1) / period; + this->phases [index] ^= count & 1; + time += count * period; + } + } + + this->delays [index] = time - end_time; + } + + this->last_time = end_time; +} + -- cgit v1.2.3