From acb0917556fc33681c1df5a530cf754193e67705 Mon Sep 17 00:00:00 2001
From: Andree Buschmann <AndreeBuschmann@t-online.de>
Date: Sun, 7 Aug 2011 20:01:04 +0000
Subject: Submit initial patch from FS#12176. Adds support for several new game
 music formats (AY, GBS, HES, KSS, SGC, VGM and VGZ) and replaces the current
 NSF and NSFE with a new implementation based on a port of the Game Music Emu
 library 'GME'. This first submit does not cover the full functionality
 provided by the author's original patch: Coleco-SGV is not supported, some
 GME-specific m3u-support has been removed and IRAM is not used yet. Further
 changes are very likely to follow this submit. Thanks to Mauricio Garrido.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30264 a1c6a512-1295-4272-9138-f99709370657
---
 apps/codecs/libgme/nes_fds_apu.h | 116 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 apps/codecs/libgme/nes_fds_apu.h

(limited to 'apps/codecs/libgme/nes_fds_apu.h')

diff --git a/apps/codecs/libgme/nes_fds_apu.h b/apps/codecs/libgme/nes_fds_apu.h
new file mode 100644
index 0000000000..1360e443db
--- /dev/null
+++ b/apps/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, double t );
+	
+// emulation
+void Fds_reset( struct Nes_Fds_Apu* this );
+
+static inline void Fds_volume( struct Nes_Fds_Apu* this, double v )
+{
+	Synth_volume( &this->synth, 0.14 / fds_master_vol_max / fds_vol_max / fds_wave_sample_max * v );
+}
+
+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 ) ICODE_ATTR;
+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 ) ICODE_ATTR;
+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
-- 
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