The first three will typically have been retrieved from a document file by an UNSAVE ('UD') operation just prior to the call to 'SA'. The second three can also have been UNSAVEd in this manner from another document file, or, if the 'SA' is performed in the same session (batch run) as the second cycle, they may simply be the current register contents (see below).
The final three registers specified are output registers, and receive the vector sums for the rotation and shift.
NOTES