From: "Paul Gilmartin" <[email protected]>
Sent: Saturday, 11 September 2010 12:15 AM
True for any discussion of whether adding a negative number
(or the two's complement of a positive number) is equivalent
(algebraically or conceptually) to subtracting its magnitude.
But the technique of stepping backward through an array by:
LA Rx,-4(Rx)
was useful at least in days of yore, and remains valid today
even though AHI may be preferable.
Not only would it be silly, it would require more code
than the conventional way.*
To do that task [of steeping backwards], a simple BCT for loop control,
and an SH or SR to decrement an index by 4 is more than adequate.
It's simple, and straightforward. i.e., the KISS principle.
