294 lines
7.2 KiB
C++
294 lines
7.2 KiB
C++
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
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#include "Gbs_Emu.h"
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#include "blargg_endian.h"
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#include <string.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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Gbs_Emu::equalizer_t const Gbs_Emu::handheld_eq =
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Music_Emu::make_equalizer( -47.0, 2000 );
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Gbs_Emu::equalizer_t const Gbs_Emu::headphones_eq =
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Music_Emu::make_equalizer( 0.0, 300 );
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Gbs_Emu::Gbs_Emu()
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{
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set_type( gme_gbs_type );
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static const char* const names [Gb_Apu::osc_count] = {
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"Square 1", "Square 2", "Wave", "Noise"
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};
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set_voice_names( names );
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static int const types [Gb_Apu::osc_count] = {
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wave_type | 1, wave_type | 2, wave_type | 0, mixed_type | 0
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};
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set_voice_types( types );
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set_silence_lookahead( 6 );
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set_max_initial_silence( 21 );
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set_gain( 1.2 );
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set_equalizer( make_equalizer( -1.0, 120 ) );
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}
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Gbs_Emu::~Gbs_Emu() { }
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void Gbs_Emu::unload()
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{
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rom.clear();
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Music_Emu::unload();
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}
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// Track info
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static void copy_gbs_fields( Gbs_Emu::header_t const& h, track_info_t* out )
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{
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GME_COPY_FIELD( h, out, game );
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GME_COPY_FIELD( h, out, author );
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GME_COPY_FIELD( h, out, copyright );
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}
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blargg_err_t Gbs_Emu::track_info_( track_info_t* out, int ) const
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{
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copy_gbs_fields( header_, out );
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return 0;
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}
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static blargg_err_t check_gbs_header( void const* header )
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{
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if ( memcmp( header, "GBS", 3 ) )
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return gme_wrong_file_type;
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return 0;
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}
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struct Gbs_File : Gme_Info_
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{
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Gbs_Emu::header_t h;
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Gbs_File() { set_type( gme_gbs_type ); }
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blargg_err_t load_( Data_Reader& in )
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{
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blargg_err_t err = in.read( &h, Gbs_Emu::header_size );
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if ( err )
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return (err == in.eof_error ? gme_wrong_file_type : err);
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set_track_count( h.track_count );
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return check_gbs_header( &h );
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}
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blargg_err_t track_info_( track_info_t* out, int ) const
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{
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copy_gbs_fields( h, out );
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return 0;
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}
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};
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static Music_Emu* new_gbs_emu () { return BLARGG_NEW Gbs_Emu ; }
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static Music_Emu* new_gbs_file() { return BLARGG_NEW Gbs_File; }
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static gme_type_t_ const gme_gbs_type_ = { "Game Boy", 0, &new_gbs_emu, &new_gbs_file, "GBS", 1 };
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extern gme_type_t const gme_gbs_type = &gme_gbs_type_;
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// Setup
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blargg_err_t Gbs_Emu::load_( Data_Reader& in )
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{
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assert( offsetof (header_t,copyright [32]) == header_size );
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RETURN_ERR( rom.load( in, header_size, &header_, 0 ) );
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set_track_count( header_.track_count );
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RETURN_ERR( check_gbs_header( &header_ ) );
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if ( header_.vers != 1 )
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set_warning( "Unknown file version" );
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if ( header_.timer_mode & 0x78 )
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set_warning( "Invalid timer mode" );
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unsigned load_addr = get_le16( header_.load_addr );
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if ( (header_.load_addr [1] | header_.init_addr [1] | header_.play_addr [1]) > 0x7F ||
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load_addr < 0x400 )
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set_warning( "Invalid load/init/play address" );
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set_voice_count( Gb_Apu::osc_count );
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apu.volume( gain() );
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return setup_buffer( 4194304 );
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}
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void Gbs_Emu::update_eq( blip_eq_t const& eq )
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{
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apu.treble_eq( eq );
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}
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void Gbs_Emu::set_voice( int i, Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r )
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{
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apu.osc_output( i, c, l, r );
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}
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// Emulation
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// see gb_cpu_io.h for read/write functions
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void Gbs_Emu::set_bank( int n )
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{
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// Only valid for MBC1 cartridges, but hopefully shouldn't hurt
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n &= 0x1f;
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if (n == 0)
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{
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n = 1;
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}
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blargg_long addr = n * (blargg_long) bank_size;
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if (addr > rom.size())
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{
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return;
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}
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cpu::map_code( bank_size, bank_size, rom.at_addr( rom.mask_addr( addr ) ) );
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}
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void Gbs_Emu::update_timer()
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{
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if ( header_.timer_mode & 0x04 )
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{
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static byte const rates [4] = { 10, 4, 6, 8 };
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int shift = rates [ram [hi_page + 7] & 3] - (header_.timer_mode >> 7);
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play_period = (256L - ram [hi_page + 6]) << shift;
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}
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else
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{
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play_period = 70224; // 59.73 Hz
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}
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if ( tempo() != 1.0 )
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play_period = blip_time_t (play_period / tempo());
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}
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static uint8_t const sound_data [Gb_Apu::register_count] = {
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0x80, 0xBF, 0x00, 0x00, 0xBF, // square 1
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0x00, 0x3F, 0x00, 0x00, 0xBF, // square 2
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0x7F, 0xFF, 0x9F, 0x00, 0xBF, // wave
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0x00, 0xFF, 0x00, 0x00, 0xBF, // noise
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0x77, 0xF3, 0xF1, // vin/volume, status, power mode
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0, 0, 0, 0, 0, 0, 0, 0, 0, // unused
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0xAC, 0xDD, 0xDA, 0x48, 0x36, 0x02, 0xCF, 0x16, // waveform data
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0x2C, 0x04, 0xE5, 0x2C, 0xAC, 0xDD, 0xDA, 0x48
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};
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void Gbs_Emu::cpu_jsr( gb_addr_t addr )
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{
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check( cpu::r.sp == get_le16( header_.stack_ptr ) );
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cpu::r.pc = addr;
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cpu_write( --cpu::r.sp, idle_addr >> 8 );
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cpu_write( --cpu::r.sp, idle_addr&0xFF );
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}
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void Gbs_Emu::set_tempo_( double t )
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{
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apu.set_tempo( t );
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update_timer();
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}
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blargg_err_t Gbs_Emu::start_track_( int track )
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{
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RETURN_ERR( Classic_Emu::start_track_( track ) );
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memset( ram, 0, 0x4000 );
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memset( ram + 0x4000, 0xFF, 0x1F00 );
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memset( ram + 0x5F00, 0, sizeof ram - 0x5F00 );
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ram [hi_page] = 0; // joypad reads back as 0
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apu.reset();
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for ( int i = 0; i < (int) sizeof sound_data; i++ )
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apu.write_register( 0, i + apu.start_addr, sound_data [i] );
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unsigned load_addr = get_le16( header_.load_addr );
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rom.set_addr( load_addr );
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cpu::rst_base = load_addr;
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cpu::reset( rom.unmapped() );
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cpu::map_code( ram_addr, 0x10000 - ram_addr, ram );
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cpu::map_code( 0, bank_size, rom.at_addr( 0 ) );
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set_bank( rom.size() > bank_size );
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ram [hi_page + 6] = header_.timer_modulo;
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ram [hi_page + 7] = header_.timer_mode;
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update_timer();
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next_play = play_period;
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cpu::r.a = track;
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cpu::r.pc = idle_addr;
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cpu::r.sp = get_le16( header_.stack_ptr );
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cpu_time = 0;
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cpu_jsr( get_le16( header_.init_addr ) );
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return 0;
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}
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blargg_err_t Gbs_Emu::run_clocks( blip_time_t& duration, int )
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{
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cpu_time = 0;
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while ( cpu_time < duration )
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{
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long count = duration - cpu_time;
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cpu_time = duration;
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bool result = cpu::run( count );
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cpu_time -= cpu::remain();
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if ( result )
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{
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if ( cpu::r.pc == idle_addr )
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{
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if ( next_play > duration )
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{
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cpu_time = duration;
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break;
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}
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if ( cpu_time < next_play )
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cpu_time = next_play;
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next_play += play_period;
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cpu_jsr( get_le16( header_.play_addr ) );
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GME_FRAME_HOOK( this );
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// TODO: handle timer rates different than 60 Hz
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}
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else if ( cpu::r.pc > 0xFFFF )
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{
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debug_printf( "PC wrapped around\n" );
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cpu::r.pc &= 0xFFFF;
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}
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else
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{
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set_warning( "Emulation error (illegal/unsupported instruction)" );
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debug_printf( "Bad opcode $%.2x at $%.4x\n",
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(int) *cpu::get_code( cpu::r.pc ), (int) cpu::r.pc );
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cpu::r.pc = (cpu::r.pc + 1) & 0xFFFF;
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cpu_time += 6;
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}
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}
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}
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duration = cpu_time;
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next_play -= cpu_time;
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if ( next_play < 0 ) // could go negative if routine is taking too long to return
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next_play = 0;
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apu.end_frame( cpu_time );
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return 0;
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}
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