Hi
IN AMIBROKER
The formula ROC( CLOSE, 14 )
returns the 14-period
percent rate-of-change of the closing prices
The metastock code you posted is
ROC(MOV((C/P),13,S),1,%)
MOV =MA
S=SIMPLE MA
MOV((C/P),13,S) = MA((C/P),13)
ROC(MA((C/P),13),1)
Is what you need