Shiftdata -  Carl Anthony Edwards Sunday, 10th March 1991

This is simply a procedure which compiles a routine which will shift an
integer multiple of 32 bytes quickly. For speed, no checks are made to see
if the destination overlaps the source block so care must be taken in its
use.

This routine may most easily be installed using the 'Install' routine within
the 'Library' section. See relevant documentation as to how to do this.

Usage :

Simply call the routine with the register R0 = source memory base
                                          R1 = destination memory base
                                          R2 = data size DIV 32

On exit, R0 = pointer to next location to read from
         R1 = pointer to next location to write to
         R2 = 0
         R3-R10 are corrupted
