ym3812 code

Author: vampirefrog

fmtoy_ym3812.c

@@ -0,0 +1,78 @@
+#include <math.h>
+#include <stdlib.h>
+
+#include "fmtoy.h"
+#include "fmtoy_ym3812.h"
+#include "chips/fmopl.h"
+
+static void fmwrite(void *ptr, uint8_t reg, uint8_t val) {
+	ym3812_write(ptr, 0, reg);
+	ym3812_write(ptr, 1, val);
+}
+
+static int fmtoy_ym3812_init(struct fmtoy *fmtoy, int clock, int sample_rate, struct fmtoy_channel *channel) {
+	channel->chip->clock = clock;
+	channel->chip->data = ym3812_init(clock, sample_rate);
+	fmwrite(channel->chip->data, 0x01, 0x20);
+
+	return 0;
+}
+
+static int fmtoy_ym3812_destroy(struct fmtoy *fmtoy, struct fmtoy_channel *channel) {
+	return 0;
+}
+
+static void fmtoy_ym3812_program_change(struct fmtoy *fmtoy, uint8_t program, struct fmtoy_channel *channel) {
+	struct fmtoy_opl_voice *v = &fmtoy->opl_voices[program];
+	int chan_offsets[] = {
+		0x00, 0x01, 0x02,
+		0x08, 0x09, 0x0a,
+		0x10, 0x11, 0x12,
+	};
+	for(int i = 0; i < 9; i++) {
+		fmwrite(channel->chip->data, 0xc0 + i, v->fb_con);
+		for(int j = 0; j < 2; j++) {
+			struct fmtoy_opl_voice_operator *op = &v->operators[j];
+			fmwrite(channel->chip->data, 0x20 + chan_offsets[i] + j * 3, op->am_vib_eg_ksr_mul);
+			fmwrite(channel->chip->data, 0x40 + chan_offsets[i] + j * 3, op->ksl_tl);
+			fmwrite(channel->chip->data, 0x60 + chan_offsets[i] + j * 3, op->ar_dr);
+			fmwrite(channel->chip->data, 0x80 + chan_offsets[i] + j * 3, op->sl_rr);
+			fmwrite(channel->chip->data, 0xe0 + chan_offsets[i] + j * 3, op->ws);
+		}
+	}
+}
+
+static void fmtoy_ym3812_set_pitch(struct fmtoy *fmtoy, int chip_channel, float pitch, struct fmtoy_channel *channel) {
+	uint8_t octave = (69 + 12 * log2(pitch / 440.0)) / 12 - 1;
+	uint16_t fnum = (144 * pitch * (1 << 18) / channel->chip->clock) / (1 << (octave - 1));
+	fmwrite(channel->chip->data, 0xb0 + chip_channel, (channel->chip->channels[chip_channel].on ? 0x20 : 0x00) | octave << 2 | (fnum >> 8 & 0x03));
+	fmwrite(channel->chip->data, 0xa0 + chip_channel, fnum & 0xff);
+}
+
+static void fmtoy_ym3812_pitch_bend(struct fmtoy *fmtoy, uint8_t chip_channel, float pitch, struct fmtoy_channel *channel) {
+	fmtoy_ym3812_set_pitch(fmtoy, chip_channel, pitch, channel);
+}
+
+static void fmtoy_ym3812_note_on(struct fmtoy *fmtoy, uint8_t chip_channel, float pitch, uint8_t velocity, struct fmtoy_channel *channel) {
+	fmtoy_ym3812_set_pitch(fmtoy, chip_channel, pitch, channel);
+}
+
+static void fmtoy_ym3812_note_off(struct fmtoy *fmtoy, uint8_t chip_channel, uint8_t velocity, struct fmtoy_channel *channel) {
+	fmwrite(channel->chip->data, 0xb0 + chip_channel, 0x00);
+}
+
+static void fmtoy_ym3812_render(struct fmtoy *fmtoy, stream_sample_t **buffers, int num_samples, struct fmtoy_channel *channel) {
+	ym3812_update_one(channel->chip->data, buffers, num_samples);
+}
+
+struct fmtoy_chip fmtoy_chip_ym3812 = {
+	.name = "YM3812",
+	.init = fmtoy_ym3812_init,
+	.destroy = fmtoy_ym3812_destroy,
+	.program_change = fmtoy_ym3812_program_change,
+	.pitch_bend = fmtoy_ym3812_pitch_bend,
+	.note_on = fmtoy_ym3812_note_on,
+	.note_off = fmtoy_ym3812_note_off,
+	.render = fmtoy_ym3812_render,
+	.max_poliphony = 9,
+};

fmtoy_ym3812.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "fmtoy.h"
+
+extern struct fmtoy_chip fmtoy_chip_ym3812;