112 lines
2.3 KiB
C++
112 lines
2.3 KiB
C++
// Konami SCC sound chip emulator
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// $package
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#ifndef KSS_SCC_APU_H
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#define KSS_SCC_APU_H
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#include "blargg_common.h"
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#include "Blip_Buffer.h"
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class Scc_Apu {
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public:
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// Basics
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// Sets buffer to generate sound into, or 0 to mute.
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void set_output( Blip_Buffer* );
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// Emulates to time t, then writes data to reg
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enum { reg_count = 0xB0 }; // 0 <= reg < reg_count
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void write( blip_time_t t, int reg, int data );
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// Emulates to time t, then subtracts t from the current time.
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// OK if previous write call had time slightly after t.
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void end_frame( blip_time_t t );
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// More features
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// Resets sound chip
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void reset();
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// Same as set_output(), but for a particular channel
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enum { osc_count = 5 };
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void set_output( int chan, Blip_Buffer* );
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// Set overall volume, where 1.0 is normal
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void volume( double );
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// Set treble equalization
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void treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
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private:
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// noncopyable
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Scc_Apu( const Scc_Apu& );
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Scc_Apu& operator = ( const Scc_Apu& );
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// Implementation
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public:
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Scc_Apu();
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BLARGG_DISABLE_NOTHROW
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private:
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enum { amp_range = 0x8000 };
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struct osc_t
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{
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int delay;
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int phase;
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int last_amp;
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Blip_Buffer* output;
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};
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osc_t oscs [osc_count];
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blip_time_t last_time;
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unsigned char regs [reg_count];
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Blip_Synth_Fast synth;
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void run_until( blip_time_t );
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};
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inline void Scc_Apu::set_output( int index, Blip_Buffer* b )
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{
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assert( (unsigned) index < osc_count );
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oscs [index].output = b;
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}
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inline void Scc_Apu::write( blip_time_t time, int addr, int data )
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{
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//assert( (unsigned) addr < reg_count );
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assert( ( addr >= 0x9800 && addr <= 0x988F ) || ( addr >= 0xB800 && addr <= 0xB8AF ) );
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run_until( time );
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addr -= 0x9800;
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if ( ( unsigned ) addr < 0x90 )
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{
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if ( ( unsigned ) addr < 0x60 )
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regs [addr] = data;
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else if ( ( unsigned ) addr < 0x80 )
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{
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regs [addr] = regs[addr + 0x20] = data;
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}
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else if ( ( unsigned ) addr < 0x90 )
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{
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regs [addr + 0x20] = data;
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}
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}
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else
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{
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addr -= 0xB800 - 0x9800;
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if ( ( unsigned ) addr < 0xB0 )
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regs [addr] = data;
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}
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}
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inline void Scc_Apu::end_frame( blip_time_t end_time )
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{
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if ( end_time > last_time )
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run_until( end_time );
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last_time -= end_time;
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assert( last_time >= 0 );
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}
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#endif
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