mulscale <Result> <Factor 1> <Factor 2> <Right Shift>
In C terms, this command performs roughly the expression
<Result> = (<Factor 1> * <Factor 2>) >> <Right Shift>.
In CON terms, it is very similar to the following series of commands:
set <Result> <Factor 1> mul <Result> <Factor 2> shiftr <Result> <Right Shift>
The main difference is that the calculation uses 64 bits to prevent overflow, while using gamevars for intermediate values would limit it to 31 bits.
sin Sine sprite.ang mulscale Result Length Sine 14