MACD line crossed the zero

Algos, strategies, code
1

Hi,
I am looking for an indicator that will alert me

BUY:
when the MACD SIGNAL line crosses the zero line from DOWN and goes UP

SELL:
when the MACD SIGNAL line crosses the zero line from UP and goes DOWN

Please advise.

2

For the above given condition

Buy Script:

SET A = MACDSignal(13, 26, 9, SIMPLE)
SET B = MACD(13, 26, 9, SIMPLE)
CROSSOVER(A, B) = TRUE

Sell Script:

SET A = MACDSignal(13, 26, 9, SIMPLE)
SET B = MACD(13, 26, 9, SIMPLE)
CROSSOVER(B, A) = TRUE