Format: copy src dest length [size] [direction]
Copies a block of memory of length units of size size from src to dest. Thus, the total size of memory copied is (length x
size). If a size is not specified, it defaults to the size of an integer. The direction of the copy is specified by direction with either a 1 (one) or forw for forward copying, or a -1 (negative one) or backw for reverse copying. If no size is given, then forw or backw should be used for the direction to avoid confusion.
Reverse copying is the same as forward copying except the starting location of the copy is src+(length x
size) and is decremented down to src. The destination of the copy is also started at dest+(length x
size) and decremented down to dest.