117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
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// Sega/Game Gear/Coleco SGC music file emulator implementation internals
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// Game_Music_Emu $vers
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#ifndef SGC_IMPL_H
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#define SGC_IMPL_H
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#include "Gme_Loader.h"
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#include "Rom_Data.h"
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#include "Z80_Cpu.h"
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class Sgc_Impl : public Gme_Loader {
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public:
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// SGC file header
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struct header_t
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{
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enum { size = 0xA0 };
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char tag [4]; // "SGC\x1A"
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byte vers; // 0x01
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byte rate; // 0=NTSC 1=PAL
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byte reserved1 [2];
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byte load_addr [2];
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byte init_addr [2];
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byte play_addr [2];
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byte stack_ptr [2];
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byte reserved2 [2];
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byte rst_addrs [7*2];
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byte mapping [4]; // Used by Sega only
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byte first_song; // Song to start playing first
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byte song_count;
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byte first_effect;
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byte last_effect;
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byte system; // 0=Master System 1=Game Gear 2=Colecovision
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byte reserved3 [23];
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char game [32]; // strings can be 32 chars, NOT terminated
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char author [32];
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char copyright [32];
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// True if header has valid file signature
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bool valid_tag() const;
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int effect_count() const { return last_effect ? last_effect - first_effect + 1 : 0; }
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};
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// Header for currently loaded file
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header_t const& header() const { return header_; }
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Rom_Data const& rom_() const { return rom; }
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int clock_rate() const { return header_.rate ? 3546893 : 3579545; }
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// 0x2000 bytes
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static void set_coleco_bios( void const* p ) { coleco_bios = p; }
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// Clocks between calls to play routine
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typedef int time_t;
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void set_play_period( time_t p ) { play_period = p; }
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// 0 = first track
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blargg_err_t start_track( int );
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// Runs for t clocks
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blargg_err_t end_frame( time_t t );
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// True if Master System or Game Gear
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bool sega_mapping() const;
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protected:
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typedef Z80_Cpu Sgc_Cpu;
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Sgc_Cpu cpu;
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typedef int addr_t;
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virtual void cpu_out( time_t, addr_t, int data ) BLARGG_PURE( ; )
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// Implementation
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public:
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Sgc_Impl();
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~Sgc_Impl();
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virtual void unload();
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protected:
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virtual blargg_err_t load_( Data_Reader& );
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private:
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enum { bank_size = 0x4000 };
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Rom_Data rom;
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time_t play_period;
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time_t next_play;
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void const* bank2; // ROM selected for bank 2, in case RAM is currently hiding it
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addr_t vectors_addr; // RST vectors start here
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addr_t idle_addr; // return address for init/play routines
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static void const* coleco_bios;
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// large items
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header_t header_;
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blargg_vector<byte> vectors;
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blargg_vector<byte> ram;
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blargg_vector<byte> ram2;
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blargg_vector<byte> unmapped_write;
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bool run_cpu( time_t end );
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void jsr( byte const (&addr) [2] );
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void cpu_write( addr_t, int data );
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int cpu_in( addr_t );
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void set_bank( int bank, void const* data );
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};
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inline bool Sgc_Impl::sega_mapping() const
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{
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return header_.system <= 1;
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}
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#endif
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