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314 lines
6.6 KiB
C++
314 lines
6.6 KiB
C++
// Game_Music_Emu 0.6.0. http://www.slack.net/~ant/
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#include "Vgm_Emu.h"
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#include <math.h>
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#include <string.h>
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#include "blargg_endian.h"
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/* Copyright (C) 2003-2006 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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enum {
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cmd_gg_stereo = 0x4F,
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cmd_psg = 0x50,
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cmd_ym2413 = 0x51,
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cmd_ym2612_port0 = 0x52,
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cmd_ym2612_port1 = 0x53,
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cmd_ym2151 = 0x54,
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cmd_delay = 0x61,
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cmd_delay_735 = 0x62,
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cmd_delay_882 = 0x63,
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cmd_byte_delay = 0x64,
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cmd_end = 0x66,
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cmd_data_block = 0x67,
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cmd_short_delay = 0x70,
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cmd_pcm_delay = 0x80,
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cmd_pcm_seek = 0xE0,
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pcm_block_type = 0x00,
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ym2612_dac_port = 0x2A
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};
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inline int command_len( int command )
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{
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switch ( command >> 4 )
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{
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case 0x03:
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case 0x04:
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return 2;
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case 0x05:
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case 0x0A:
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case 0x0B:
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return 3;
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case 0x0C:
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case 0x0D:
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return 4;
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case 0x0E:
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case 0x0F:
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return 5;
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}
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check( false );
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return 1;
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}
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template<class Emu>
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inline void Ym_Emu<Emu>::begin_frame( short* p )
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{
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require( enabled() );
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out = p;
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last_time = 0;
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}
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template<class Emu>
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inline int Ym_Emu<Emu>::run_until( int time )
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{
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int count = time - last_time;
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if ( count > 0 )
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{
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if ( last_time < 0 )
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return false;
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last_time = time;
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short* p = out;
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out += count * Emu::out_chan_count;
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Emu::run( count, p );
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}
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return true;
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}
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inline Vgm_Emu_Impl::fm_time_t Vgm_Emu_Impl::to_fm_time( vgm_time_t t ) const
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{
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return (t * fm_time_factor + fm_time_offset) >> fm_time_bits;
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}
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inline blip_time_t Vgm_Emu_Impl::to_blip_time( vgm_time_t t ) const
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{
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return (t * blip_time_factor) >> blip_time_bits;
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}
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void Vgm_Emu_Impl::write_pcm( vgm_time_t vgm_time, int amp )
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{
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blip_time_t blip_time = to_blip_time( vgm_time );
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int old = dac_amp;
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int delta = amp - old;
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dac_amp = amp;
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if ( old >= 0 )
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dac_synth.offset_inline( blip_time, delta, &blip_buf );
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else
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dac_amp |= dac_disabled;
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}
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blip_time_t Vgm_Emu_Impl::run_commands( vgm_time_t end_time )
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{
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vgm_time_t vgm_time = this->vgm_time;
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byte const* pos = this->pos;
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if ( pos >= data_end )
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{
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set_track_ended();
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if ( pos > data_end )
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set_warning( "Stream lacked end event" );
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}
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while ( vgm_time < end_time && pos < data_end )
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{
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// TODO: be sure there are enough bytes left in stream for particular command
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// so we don't read past end
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switch ( *pos++ )
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{
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case cmd_end:
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pos = loop_begin; // if not looped, loop_begin == data_end
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break;
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case cmd_delay_735:
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vgm_time += 735;
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break;
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case cmd_delay_882:
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vgm_time += 882;
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break;
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case cmd_gg_stereo:
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psg.write_ggstereo( to_blip_time( vgm_time ), *pos++ );
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break;
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case cmd_psg:
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psg.write_data( to_blip_time( vgm_time ), *pos++ );
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break;
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case cmd_delay:
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vgm_time += pos [1] * 0x100L + pos [0];
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pos += 2;
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break;
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case cmd_byte_delay:
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vgm_time += *pos++;
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break;
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case cmd_ym2413:
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if ( ym2413.run_until( to_fm_time( vgm_time ) ) )
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ym2413.write( pos [0], pos [1] );
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pos += 2;
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break;
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case cmd_ym2612_port0:
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if ( pos [0] == ym2612_dac_port )
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{
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write_pcm( vgm_time, pos [1] );
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}
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else if ( ym2612.run_until( to_fm_time( vgm_time ) ) )
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{
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if ( pos [0] == 0x2B )
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{
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dac_disabled = (pos [1] >> 7 & 1) - 1;
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dac_amp |= dac_disabled;
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}
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ym2612.write0( pos [0], pos [1] );
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}
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pos += 2;
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break;
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case cmd_ym2612_port1:
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if ( ym2612.run_until( to_fm_time( vgm_time ) ) )
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ym2612.write1( pos [0], pos [1] );
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pos += 2;
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break;
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case cmd_data_block: {
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check( *pos == cmd_end );
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int type = pos [1];
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long size = get_le32( pos + 2 );
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pos += 6;
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if ( type == pcm_block_type )
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pcm_data = pos;
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pos += size;
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break;
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}
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case cmd_pcm_seek:
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pcm_pos = pcm_data + pos [3] * 0x1000000L + pos [2] * 0x10000L +
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pos [1] * 0x100L + pos [0];
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pos += 4;
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break;
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default:
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int cmd = pos [-1];
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switch ( cmd & 0xF0 )
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{
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case cmd_pcm_delay:
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write_pcm( vgm_time, *pcm_pos++ );
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vgm_time += cmd & 0x0F;
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break;
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case cmd_short_delay:
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vgm_time += (cmd & 0x0F) + 1;
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break;
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case 0x50:
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pos += 2;
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break;
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default:
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pos += command_len( cmd ) - 1;
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set_warning( "Unknown stream event" );
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}
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}
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}
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vgm_time -= end_time;
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this->pos = pos;
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this->vgm_time = vgm_time;
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return to_blip_time( end_time );
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}
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int Vgm_Emu_Impl::play_frame( blip_time_t blip_time, int sample_count, sample_t* buf )
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{
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// to do: timing is working mostly by luck
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int min_pairs = sample_count >> 1;
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int vgm_time = ((long) min_pairs << fm_time_bits) / fm_time_factor - 1;
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assert( to_fm_time( vgm_time ) <= min_pairs );
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int pairs = min_pairs;
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while ( (pairs = to_fm_time( vgm_time )) < min_pairs )
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vgm_time++;
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//debug_printf( "pairs: %d, min_pairs: %d\n", pairs, min_pairs );
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if ( ym2612.enabled() )
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{
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ym2612.begin_frame( buf );
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memset( buf, 0, pairs * stereo * sizeof *buf );
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}
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else if ( ym2413.enabled() )
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{
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ym2413.begin_frame( buf );
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}
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run_commands( vgm_time );
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ym2612.run_until( pairs );
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ym2413.run_until( pairs );
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fm_time_offset = (vgm_time * fm_time_factor + fm_time_offset) -
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((long) pairs << fm_time_bits);
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psg.end_frame( blip_time );
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return pairs * stereo;
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}
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// Update pre-1.10 header FM rates by scanning commands
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void Vgm_Emu_Impl::update_fm_rates( long* ym2413_rate, long* ym2612_rate ) const
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{
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byte const* p = data + 0x40;
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while ( p < data_end )
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{
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switch ( *p )
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{
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case cmd_end:
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return;
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case cmd_psg:
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case cmd_byte_delay:
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p += 2;
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break;
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case cmd_delay:
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p += 3;
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break;
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case cmd_data_block:
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p += 7 + get_le32( p + 3 );
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break;
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case cmd_ym2413:
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*ym2612_rate = 0;
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return;
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case cmd_ym2612_port0:
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case cmd_ym2612_port1:
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*ym2612_rate = *ym2413_rate;
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*ym2413_rate = 0;
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return;
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case cmd_ym2151:
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*ym2413_rate = 0;
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*ym2612_rate = 0;
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return;
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default:
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p += command_len( *p );
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}
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}
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}
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