Moving Average Convergence/Divergence

study(title="Moving Average Convergence/Divergence", shorttitle="SLG-MACD")
source = close
fastLength = input(8, minval=1), slowLength=input(21,minval=1)
signalLength=input(5,minval=1)
fastMA = ema(source, fastLength)
slowMA = ema(source, slowLength)
macd = fastMA - slowMA
signal = sma(macd, signalLength)
hist = macd - signal
plot(hist, color=black, style=histogram)
plot(macd, color=red, linewidth=3)
plot(signal, color=green, linewidth=3)
plot(cross(macd, signal) ? macd : na, color=black, style = cross, linewidth = 10)