1 files changed, 90 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libgme/nes_fme7_apu.h b/lib/rbcodec/codecs/libgme/nes_fme7_apu.h
new file mode 100644
index 0000000000..c0eac4c765
--- /dev/null
+++ b/lib/rbcodec/codecs/libgme/nes_fme7_apu.h
@@ -0,0 +1,90 @@
+// Sunsoft FME-7 sound emulator
+
+// Game_Music_Emu 0.6-pre
+#ifndef NES_FME7_APU_H
+#define NES_FME7_APU_H
+
+#include "blargg_common.h"
+#include "blip_buffer.h"
+
+enum { fme7_reg_count = 14 };
+
+// Mask and addresses of registers
+enum { fme7_addr_mask = 0xE000 };
+enum { fme7_data_addr = 0xE000 };
+enum { fme7_latch_addr = 0xC000 };
+enum { fme7_osc_count = 3 };
+
+enum { amp_range = 192 }; // can be any value; this gives best error/quality tradeoff
+
+struct osc_t {
+        struct Blip_Buffer* output;
+        int last_amp;
+};
+
+// static unsigned char const amp_table [16];
+
+struct Nes_Fme7_Apu {
+        // fme7 apu state
+        uint8_t regs [fme7_reg_count];
+        uint8_t phases [3]; // 0 or 1
+        uint8_t latch;
+        uint16_t delays [3]; // a, b, c
+        
+        struct osc_t oscs [fme7_osc_count];
+        blip_time_t last_time;
+        
+        struct Blip_Synth synth;
+};
+
+// See Nes_Apu.h for reference
+void Fme7_init( struct Nes_Fme7_Apu* this );
+void Fme7_reset( struct Nes_Fme7_Apu* this );
+        
+static inline void Fme7_volume( struct Nes_Fme7_Apu* this, int v )
+{
+        Synth_volume( &this->synth, (v/2 - (v*3)/25) / amp_range ); // to do: fine-tune
+}
+
+static inline void Fme7_osc_output( struct Nes_Fme7_Apu* this, int i, struct Blip_Buffer* buf )
+{
+        assert( (unsigned) i < fme7_osc_count );
+        this->oscs [i].output = buf;
+}
+
+static inline void Fme7_output( struct Nes_Fme7_Apu* this, struct Blip_Buffer* buf )
+{
+        int i;
+        for ( i = 0; i < fme7_osc_count; i++ )
+                Fme7_osc_output( this, i, buf );
+}
+
+// (addr & addr_mask) == latch_addr
+static inline void Fme7_write_latch( struct Nes_Fme7_Apu* this, int data ) { this->latch = data; }
+
+// (addr & addr_mask) == data_addr
+void Fme7_run_until( struct Nes_Fme7_Apu* this, blip_time_t end_time );
+static inline void Fme7_write_data( struct Nes_Fme7_Apu* this, blip_time_t time, int data )
+{
+        if ( (unsigned) this->latch >= fme7_reg_count )
+        {
+                #ifdef debug_printf
+                        debug_printf( "FME7 write to %02X (past end of sound registers)\n", (int) latch );
+                #endif
+                return;
+        }
+        
+        Fme7_run_until( this, time );
+        this->regs [this->latch] = data;
+}
+
+static inline void Fme7_end_frame( struct Nes_Fme7_Apu* this, blip_time_t time )
+{
+        if ( time > this->last_time )
+                Fme7_run_until( this, time );
+        
+        assert( this->last_time >= time );
+        this->last_time -= time;
+}
+
+#endif