1 files changed, 97 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6.0/gme/Kss_Scc_Apu.cpp b/plugins/gme/game-music-emu-0.6.0/gme/Kss_Scc_Apu.cpp
new file mode 100644
index 00000000..cfccce64
--- /dev/null
+++ b/plugins/gme/game-music-emu-0.6.0/gme/Kss_Scc_Apu.cpp
@@ -0,0 +1,97 @@
+// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/
+
+#include "Kss_Scc_Apu.h"
+
+/* Copyright (C) 2006 Shay Green. This module is free software; you
+can redistribute it and/or modify it under the terms of the GNU Lesser
+General Public License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version. This
+module is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+details. You should have received a copy of the GNU Lesser General Public
+License along with this module; if not, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
+
+#include "blargg_source.h"
+
+// Tones above this frequency are treated as disabled tone at half volume.
+// Power of two is more efficient (avoids division).
+unsigned const inaudible_freq = 16384;
+
+int const wave_size = 0x20;
+
+void Scc_Apu::run_until( blip_time_t end_time )
+{
+	for ( int index = 0; index < osc_count; index++ )
+	{
+		osc_t& osc = oscs [index];
+		
+		Blip_Buffer* const output = osc.output;
+		if ( !output )
+			continue;
+		output->set_modified();
+		
+		blip_time_t period = (regs [0x80 + index * 2 + 1] & 0x0F) * 0x100 +
+				regs [0x80 + index * 2] + 1;
+		int volume = 0;
+		if ( regs [0x8F] & (1 << index) )
+		{
+			blip_time_t inaudible_period = (blargg_ulong) (output->clock_rate() +
+					inaudible_freq * 32) / (inaudible_freq * 16);
+			if ( period > inaudible_period )
+				volume = (regs [0x8A + index] & 0x0F) * (amp_range / 256 / 15);
+		}
+		
+		BOOST::int8_t const* wave = (BOOST::int8_t*) regs + index * wave_size;
+		if ( index == osc_count - 1 )
+			wave -= wave_size; // last two oscs share wave
+		{
+			int amp = wave [osc.phase] * volume;
+			int delta = amp - osc.last_amp;
+			if ( delta )
+			{
+				osc.last_amp = amp;
+				synth.offset( last_time, delta, output );
+			}
+		}
+		
+		blip_time_t time = last_time + osc.delay;
+		if ( time < end_time )
+		{
+			if ( !volume )
+			{
+				// maintain phase
+				blargg_long count = (end_time - time + period - 1) / period;
+				osc.phase = (osc.phase + count) & (wave_size - 1);
+				time += count * period;
+			}
+			else
+			{
+				
+				int phase = osc.phase;
+				int last_wave = wave [phase];
+				phase = (phase + 1) & (wave_size - 1); // pre-advance for optimal inner loop
+				
+				do
+				{
+					int amp = wave [phase];
+					phase = (phase + 1) & (wave_size - 1);
+					int delta = amp - last_wave;
+					if ( delta )
+					{
+						last_wave = amp;
+						synth.offset( time, delta * volume, output );
+					}
+					time += period;
+				}
+				while ( time < end_time );
+				
+				osc.phase = phase = (phase - 1) & (wave_size - 1); // undo pre-advance
+				osc.last_amp = wave [phase] * volume;
+			}
+		}
+		osc.delay = time - end_time;
+	}
+	last_time = end_time;
+}