1 files changed, 85 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libgme/gb_apu.h b/lib/rbcodec/codecs/libgme/gb_apu.h
new file mode 100644
index 0000000000..69307b9840
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+++ b/lib/rbcodec/codecs/libgme/gb_apu.h
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+// Nintendo Game Boy sound hardware emulator with save state support
+
+// Gb_Snd_Emu 0.1.4
+#ifndef GB_APU_H
+#define GB_APU_H
+
+#include "gb_oscs.h"
+
+// Clock rate sound hardware runs at
+enum { clock_rate = 4194304 * GB_APU_OVERCLOCK };
+        
+// Registers are at io_addr to io_addr+io_size-1
+enum { io_addr = 0xFF10 };
+enum { io_size = 0x30 };
+enum { regs_size = io_size + 0x10 };
+        
+enum gb_mode_t {
+        mode_dmg,   // Game Boy monochrome
+        mode_cgb,   // Game Boy Color
+        mode_agb    // Game Boy Advance
+};
+
+// 0: Square 1, 1: Square 2, 2: Wave, 3: Noise
+enum { osc_count = 4 }; // 0 <= chan < osc_count
+
+struct Gb_Apu {
+        struct Gb_Osc*     oscs [osc_count];
+        blip_time_t last_time;          // time sound emulator has been run to
+        blip_time_t frame_period;       // clocks between each frame sequencer step
+        int      volume_;
+        bool        reduce_clicks_;
+        
+        struct Gb_Square square1;
+        struct Gb_Square square2;
+        struct Gb_Wave   wave;
+        struct Gb_Noise  noise;
+        blip_time_t     frame_time;     // time of next frame sequencer action
+        int             frame_phase;    // phase of next frame sequencer step
+        
+        uint8_t  regs [regs_size];// last values written to registers
+        
+        // large objects after everything else
+        struct Blip_Synth synth;
+};
+
+// Basics
+
+// Initializes apu
+void Apu_init( struct Gb_Apu* this );
+        
+// Emulates to time t, then writes data to addr
+void Apu_write_register( struct Gb_Apu* this, blip_time_t t, int addr, int data );
+        
+// Emulates to time t, then subtracts t from the current time.
+// OK if previous write call had time slightly after t.
+void Apu_end_frame( struct Gb_Apu* this,blip_time_t t );
+        
+// More features
+        
+// Emulates to time t, then reads from addr
+int Apu_read_register( struct Gb_Apu* this, blip_time_t t, int addr );
+
+// Resets hardware to state after power, BEFORE boot ROM runs. Mode selects
+// sound hardware. If agb_wave is true, enables AGB's extra wave features.
+void Apu_reset( struct Gb_Apu* this, enum gb_mode_t mode, bool agb_wave );
+        
+// Same as set_output(), but for a particular channel
+void Apu_set_output( struct Gb_Apu* this, int chan, struct Blip_Buffer* center,
+                struct Blip_Buffer* left, struct Blip_Buffer* right );
+        
+// Sets overall volume, where 1.0 is normal
+void Apu_volume( struct Gb_Apu* this, int v );
+        
+// If true, reduces clicking by disabling DAC biasing. Note that this reduces
+// emulation accuracy, since the clicks are authentic.
+void Apu_reduce_clicks( struct Gb_Apu* this, bool reduce );
+        
+// Sets frame sequencer rate, where 1.0 is normal. Meant for adjusting the
+// tempo in a music player.
+void Apu_set_tempo( struct Gb_Apu* this, int t );
+
+
+void write_osc( struct Gb_Apu* this, int reg, int old_data, int data );
+
+#endif