Outside links:
https://en.wikipedia.org/wiki/MACD
https://en.wikipedia.org/wiki/Moving...moving_average

Do you intend to use a simple average over time or an actual Exponential moving average when computing MACD?

Also, I recommend using Constants for the Number of periods used in averages so that you can easily tweak the "Program."
macdA = 12
macdB = 26
macdC = 9

The A and B average arrays can be simple FIFO arrangements, but if you use Exponential averages you would need two more to hold the weighted values to compute averages from. Don't worry too much about the number of Arrays invovled. A gazillion Arrays are still faster than a spreadsheet doing 100 calculations.