5.20. Shift Cyclic, Count in Register


Addr
Mode  Mnemonic          Format/Opcode
                           8      4      4
                        ----------------------
R     SCR   RA,RB       |  6C  |  RA  |  RB  |    |(RB)| <= 16
                        ----------------------

Description. The contents of register RA are shifted cyclically N positions, where N is the contents of register RB. If N is positive ((RB0) = 0), then the shift direction is left; if N is negative (2's complement notation, (RB0) = 1), then the shift direction is right. The condition status, CS, is set based on the result in RA.

Note: N = 0 represents a shift of zero positions.

Note: If |N| >= 16, the fixed point overflow occurs, no shifting takes place, and this instruction is treated as a NOP (see Section 5.96).

Note: (See "Description" of the cyclic shift instruction, SLC (see Section 5.13), for definition of shift operations.)

Note: The contents of RB remain unchanged, unless RA = RB in this event, the contents are shifted N positions.

Register Transfer Description.

PI4 <-- 1, exit, if |N| >= 16;
(RA) <-- (RA) Shifted left cyclically by (RB) positions,
 if 0 < (RB) <= 16;
(RA) <-- (RA) Shifted right cyclically by -(RB) positions,
 if 0 >= (RB) >== -16;
(CS) <-- 0010  if (RA) = 0;
(CS) <-- 0001  if (RA) < 0;
(CS) <-- 0100  if (RA) > 0;



Registers Affected. RA, RB, CS, PI