Add NEC D65010G031 support

chip flag and instrument color is placeholder

src/engine/platform/sound/d65010g031.c

@@ -0,0 +1,86 @@
+/*
+
+============================================================================
+
+NEC D65010G031 sound emulator
+by cam900
+
+This file is licensed under zlib license.
+
+============================================================================
+
+zlib License
+
+(C) 2023-present cam900 and contributors
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+
+============================================================================
+
+TODO:
+- needs hardware test
+
+*/
+
+#include "d65010g031.h"
+#include <stdlib.h>
+
+static int d65010g031_max(int a, int b) { return (a > b) ? a : b; }
+
+int d65010g031_square_tick(struct d65010g031_square_t *square, const int cycle)
+{
+	if (square->period > 0)
+	{
+		int period = d65010g031_max(1, (0x3f - square->period));
+		square->counter += cycle;
+		while (square->counter >= period)
+		{
+			square->counter -= period;
+			square->out ^= 1;
+		}
+		return square->out;
+	}
+	return 0;
+}
+
+int d65010g031_sound_tick(struct d65010g031_t *d65010g031, const int cycle)
+{
+	int out = 0;
+	for (int i = 0; i < 3; i++)
+	{
+		out += d65010g031_square_tick(&d65010g031->square[i], cycle);
+	}
+	return out;
+}
+
+void d65010g031_reset(struct d65010g031_t *d65010g031)
+{
+	for (int i = 0; i < 3; i++)
+	{
+		d65010g031->square[i].period = 0;
+		d65010g031->square[i].counter = 0;
+		d65010g031->square[i].out = 0;
+	}
+}
+
+void d65010g031_write(struct d65010g031_t *d65010g031, const unsigned char a, const unsigned char d)
+{
+	if (a < 3)
+	{
+		d65010g031->square[a].period = d & 0x3f;
+	}
+}

src/engine/platform/sound/d65010g031.h

@@ -0,0 +1,71 @@
+/*
+
+============================================================================
+
+NEC D65010G031 sound emulator
+by cam900
+
+This file is licensed under zlib license.
+
+============================================================================
+
+zlib License
+
+(C) 2023-present cam900 and contributors
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+
+============================================================================
+
+TODO:
+- needs hardware test
+
+*/
+
+#ifndef _D65010G031_EMU_H
+#define _D65010G031_EMU_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+struct d65010g031_square_t
+{
+	unsigned char period; // Period (0 = Off)
+	int counter; // clock counter
+	signed short out; // output
+};
+
+struct d65010g031_t
+{
+	struct d65010g031_square_t square[3];
+};
+
+int d65010g031_square_tick(struct d65010g031_square_t *square, const int cycle);
+
+int d65010g031_sound_tick(struct d65010g031_t *d65010g031, const int cycle);
+
+void d65010g031_reset(struct d65010g031_t *d65010g031);
+
+void d65010g031_write(struct d65010g031_t *d65010g031, const unsigned char a, const unsigned char d);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // _D65010G031_EMU_H