RRAΒΆ

RRA
Rotate Right Accumulator
Description
Performs a very fast RR A; the 0th bit of A is moved into the carry, and the carry is moved into the 7th bit of A.
../../_images/rr.png
Uses
  • Quickly dividing A by two (carry flag is set if there was a remainder)
  • Retrieving consecutive bits of a byte in a loop, starting from the right
Results
Register/Flag 8-bit
A ../../_images/rr1.png
S flag Not affected
Z flag Not affected
H flag Reset
P/V flag Not affected
N flag Reset
C flag 0th bit of A
Allowed Instructions
Instruction Opcode CC (ADL/non-ADL)
rra $1F 1F
Notes
  • When using RRA to divide A by 2, first make sure the carry flag is reset or the result will be ( A * 2 ) + ( 128 * Carry ).
  • Unlike RR A, this instruction does not meaningfully affect any flags except C.
See Also
RLA, RR, RRCA