1 files changed, 79 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libgme/ay_apu.h b/lib/rbcodec/codecs/libgme/ay_apu.h
new file mode 100644
index 0000000000..3df6ba1118
--- /dev/null
+++ b/lib/rbcodec/codecs/libgme/ay_apu.h
@@ -0,0 +1,79 @@
+// AY-3-8910 sound chip ulator
+
+// Game_Music_Emu 0.6-pre
+#ifndef AY_APU_H
+#define AY_APU_H
+
+#include "blargg_common.h"
+#include "blargg_source.h"
+#include "blip_buffer.h"
+
+// Number of registers
+enum { ay_reg_count = 16 };
+enum { ay_osc_count = 3 };
+enum { ay_amp_range = 255 };
+
+struct osc_t
+{
+        blip_time_t  period;
+        blip_time_t  delay;
+        short        last_amp;
+        short        phase;
+        struct Blip_Buffer* output;
+};
+
+struct Ay_Apu {
+        struct osc_t oscs [ay_osc_count];
+        
+        blip_time_t last_time;
+        byte        addr_;
+        byte        regs [ay_reg_count];
+        
+        blip_time_t noise_delay;
+        unsigned    noise_lfsr;
+        
+        blip_time_t env_delay;
+        byte const* env_wave;
+        int         env_pos;
+        byte        env_modes [8] [48]; // values already passed through volume table
+                
+        struct Blip_Synth synth_; // used by Ay_Core for beeper sound
+};
+        
+void Ay_apu_init( struct Ay_Apu* this );
+
+// Writes to address register
+static inline void Ay_apu_write_addr( struct Ay_Apu* this, int data ) { this->addr_ = data & 0x0F; }
+        
+// Emulates to time t, then writes to current data register
+void run_until( struct Ay_Apu* this, blip_time_t final_end_time );;
+void write_data_( struct Ay_Apu* this, int addr, int data );
+static inline void Ay_apu_write_data( struct Ay_Apu* this, blip_time_t t, int data )  { run_until( this, t ); write_data_( this, this->addr_, data ); }
+        
+// Reads from current data register
+int Ay_apu_read( struct Ay_Apu* this );
+        
+// Resets sound chip
+void Ay_apu_reset( struct Ay_Apu* this );
+                
+// Sets overall volume, where 1.0 is normal
+static inline void Ay_apu_volume( struct Ay_Apu* this, int v ) { Synth_volume( &this->synth_, (v*7)/10 /ay_osc_count/ay_amp_range ); }
+
+static inline void Ay_apu_set_output( struct Ay_Apu* this, int i, struct Blip_Buffer* out )
+{
+        assert( (unsigned) i < ay_osc_count );
+        this->oscs [i].output = out;
+}
+
+// Emulates to time t, then subtracts t from the current time.
+// OK if previous write call had time slightly after t.
+static inline void Ay_apu_end_frame( struct Ay_Apu* this, blip_time_t time )
+{
+        if ( time > this->last_time )
+                run_until( this, time );
+        
+        this->last_time -= time;
+        assert( this->last_time >= 0 );
+}
+
+#endif