1 files changed, 60 insertions, 0 deletions
diff --git a/libopna/opnassg.h b/libopna/opnassg.h
new file mode 100644
index 0000000..5928c49
--- /dev/null
+++ b/libopna/opnassg.h
@@ -0,0 +1,60 @@
+#ifndef LIBOPNA_OPNASSG_H_INCLUDED
+#define LIBOPNA_OPNASSG_H_INCLUDED
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct opna_ssg_ch {
+  uint16_t tone_counter;
+  bool out;
+};
+
+struct opna_ssg {
+  uint8_t regs[0x10];
+  struct opna_ssg_ch ch[3];
+  uint8_t noise_counter;
+  uint32_t lfsr;
+  uint16_t env_counter;
+  uint8_t env_level;
+  bool env_att;
+  bool env_alt;
+  bool env_hld;
+  bool env_holding;
+};
+
+struct opna_ssg_resampler {
+  int16_t buf[(1<<7)];
+  unsigned index;
+};
+
+void opna_ssg_reset(struct opna_ssg *ssg);
+void opna_ssg_resampler_reset(struct opna_ssg_resampler *resampler);
+// generate raw data
+// Monoral
+// Output level: [-32766, 32766]
+// Samplerate: clock / 8
+// (on opna: masterclock / 32
+// 7987200 / 32 = 249600)
+void opna_ssg_generate_raw(struct opna_ssg *ssg, int16_t *buf, int samples);
+
+// mix samplerate converted data for mixing with OPNA output
+// call to buffer written with OPNA output
+// samplerate: 7987200/144 Hz
+//            (55466.66..) Hz
+void opna_ssg_mix_55466(
+  struct opna_ssg *ssg, struct opna_ssg_resampler *resampler,
+  int16_t *buf, int samples);
+void opna_ssg_writereg(struct opna_ssg *ssg, unsigned reg, unsigned val);
+
+// channel level (0 - 31)
+int opna_ssg_channel_level(const struct opna_ssg *ssg, int ch);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // LIBOPNA_OPNASSG_H_INCLUDED