62 lines
1.3 KiB
C++
62 lines
1.3 KiB
C++
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
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// NES MMC5 sound chip emulator
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#ifndef NES_MMC5_APU_H
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#define NES_MMC5_APU_H
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#include "blargg_common.h"
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#include "Nes_Apu.h"
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class Nes_Mmc5_Apu : public Nes_Apu {
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public:
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enum { regs_addr = 0x5000 };
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enum { regs_size = 0x16 };
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enum { osc_count = 3 };
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void write_register( blip_time_t, unsigned addr, int data );
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void osc_output( int i, Blip_Buffer* );
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enum { exram_size = 1024 };
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unsigned char exram [exram_size];
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};
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inline void Nes_Mmc5_Apu::osc_output( int i, Blip_Buffer* b )
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{
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// in: square 1, square 2, PCM
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// out: square 1, square 2, skipped, skipped, PCM
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assert( (unsigned) i < osc_count );
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if ( i > 1 )
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i += 2;
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Nes_Apu::osc_output( i, b );
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}
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inline void Nes_Mmc5_Apu::write_register( blip_time_t time, unsigned addr, int data )
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{
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switch ( addr )
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{
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case 0x5015: // channel enables
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data &= 0x03; // enable the square waves only
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// fall through
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case 0x5000: // Square 1
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case 0x5002:
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case 0x5003:
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case 0x5004: // Square 2
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case 0x5006:
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case 0x5007:
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case 0x5011: // DAC
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Nes_Apu::write_register( time, addr - 0x1000, data );
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break;
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case 0x5010: // some things write to this for some reason
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break;
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#ifdef BLARGG_DEBUG_H
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default:
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debug_printf( "Unmapped MMC5 APU write: $%04X <- $%02X\n", addr, data );
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#endif
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}
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}
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#endif
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