1 files changed, 116 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libgme/nes_fds_apu.h b/lib/rbcodec/codecs/libgme/nes_fds_apu.h
new file mode 100644
index 0000000000..8dac3b721a
--- /dev/null
+++ b/lib/rbcodec/codecs/libgme/nes_fds_apu.h
@@ -0,0 +1,116 @@
+// NES FDS sound chip emulator
+
+// Game_Music_Emu 0.6-pre
+#ifndef NES_FDS_APU_H
+#define NES_FDS_APU_H
+
+#include "blargg_common.h"
+#include "blip_buffer.h"
+
+enum { lfo_base_tempo = 8 };
+enum { fds_osc_count = 1 };
+
+enum { fds_io_addr = 0x4040 };
+enum { fds_io_size = 0x53 };
+
+enum { fds_wave_size       = 0x40 };
+enum { fds_master_vol_max  =   10 };
+enum { fds_vol_max         = 0x20 };
+enum { fds_wave_sample_max = 0x3F };
+
+struct Nes_Fds_Apu {
+        unsigned char regs_ [fds_io_size];// last written value to registers
+        int lfo_tempo; // normally 8; adjusted by set_tempo()   
+        
+        int env_delay;
+        int env_speed;
+        int env_gain;
+        
+        int sweep_delay;
+        int sweep_speed;
+        int sweep_gain;
+        
+        int wave_pos;
+        int last_amp;
+        blip_time_t wave_fract;
+        
+        int mod_fract;
+        int mod_pos;
+        int mod_write_pos;
+        unsigned char mod_wave [fds_wave_size];
+        
+        // synthesis
+        blip_time_t last_time;
+        struct Blip_Buffer* output_;
+        struct Blip_Synth synth;
+};
+
+// init
+void Fds_init( struct Nes_Fds_Apu* this );
+// setup
+void Fds_set_tempo( struct Nes_Fds_Apu* this, int t );
+        
+// emulation
+void Fds_reset( struct Nes_Fds_Apu* this );
+
+static inline void Fds_volume( struct Nes_Fds_Apu* this, int v )
+{
+        Synth_volume( &this->synth, (v*14) / 100 / fds_master_vol_max / fds_vol_max / fds_wave_sample_max );
+}
+
+static inline void Fds_set_output( struct Nes_Fds_Apu* this, int i, struct Blip_Buffer* b )
+{
+#if defined(ROCKBOX)
+        (void) i;
+#endif
+
+        assert( (unsigned) i < fds_osc_count );
+        this->output_ = b;
+}
+
+void Fds_run_until( struct Nes_Fds_Apu* this, blip_time_t );
+static inline void Fds_end_frame( struct Nes_Fds_Apu* this, blip_time_t end_time )
+{
+        if ( end_time > this->last_time )
+                Fds_run_until( this, end_time );
+        this->last_time -= end_time;
+        assert( this->last_time >= 0 );
+}
+
+void Fds_write_( struct Nes_Fds_Apu* this, unsigned addr, int data );
+static inline void Fds_write( struct Nes_Fds_Apu* this, blip_time_t time, unsigned addr, int data )
+{
+        Fds_run_until( this, time );
+        Fds_write_( this, addr, data );
+}
+
+static inline int Fds_read( struct Nes_Fds_Apu* this, blip_time_t time, unsigned addr )
+{
+        Fds_run_until( this, time );
+        
+        int result = 0xFF;
+        switch ( addr )
+        {
+        case 0x4090:
+                result = this->env_gain;
+                break;
+        
+        case 0x4092:
+                result = this->sweep_gain;
+                break;
+        
+        default:
+                {
+                        unsigned i = addr - fds_io_addr;
+                        if ( i < fds_wave_size )
+                                result = this->regs_ [i];
+                }
+        }
+        
+        return result | 0x40;
+}
+
+// allow access to registers by absolute address (i.e. 0x4080)
+static inline unsigned char* regs_nes( struct Nes_Fds_Apu* this, unsigned addr ) { return &this->regs_ [addr - fds_io_addr]; }
+
+#endif