MIDI to frequency for MOS 6581

freq.c

#include <stdio.h>
#include <stdint.h>

int main() {

    // B7, G7 & G#7 intentionally differ from the hex values in the data sheet
    static int octave[12] = {0x892B, 0x9153, 0x99F7, 0xA31F, 0xACD2, 0xB719, 0xC1FC,
        0xCD85, 0xD9BD, 0xE6B0, 0xF467, 0x102F0};

    for (int i = 0; i < 95; i++) {
        int note = octave[i % 12];
        //printf("Note: %x\n", note);
        //printf("Octave: %d\n", i / 12);
        note = note >> (7 - (i / 12));
        uint8_t freqLo = note & 0xFF;
        uint8_t freqHi = note >> 8;

        printf("Output: %d > %x %x\n", i, freqHi, freqLo);
    }
}