HP HP-28S - Page 179

Moving Stack Objects. These commands rearrange the objects on
the stack; the number of objects doesn't change. Commands preceded
by "n" require a real-number argument.
Command Description
SWAP Moves the object in level 2 to level 1.
ROT
Moves
the object in level 3 to level
1.
n ROLL Moves the object in level n to level 1.
n ROLLD Moves the object in level 1 to level n.
The command names ROT (rotate), ROLL, and ROLLD (roll down) are
descriptive of the motion of objects as a block. ROT moves the object
in level 3 to
levell, rotating a block of three objects; ROLL and
ROLLD roll blocks of n objects.
Copying Stack Objects.
These commands return a copy of one or
more stack objects. Copying only one object returns the copy to level
1
and lifts the other objects on the stack (including the original object)
to a
higher level. When you copy more than one object, they're copied
as a block
in a similar manner. Commands preceded by "n" require a
real-number argument.
Command Description
DUP Copy the object in level 1. (When no command line is
present, you can execute DUP by pressing I ENTER I.)
OVER Copy the object in level 2.
n PICK Copy the object in level n.
DUP2 Copy the objects in levels 1 and 2.
n DUPN Copy the objects in levels 1 through n.
178 19: The Stack