RLAΒΆ

RLA
Rotate Left Accumulator
Description
Performs a very fast RL A; the 7th bit of A is moved into the carry, and the carry is moved into the 0th bit of A.
../../_images/rl.png
Uses
  • Quickly multiplying A by two
  • Retrieving consecutive bits of a byte in a loop, starting from the left
Results
Register/Flag 8-bit
A ../../_images/rl1.png
S flag Not affected
Z flag Not affected
H flag Reset
P/V flag Not affected
N flag Reset
C flag 7th bit of A
Allowed Instructions
Instruction Opcode CC (ADL/non-ADL)
rla $17 1F
Notes
  • When using RLA to multiply A by 2, first make sure the carry flag is reset the result will be ( A * 2 ) + Carry.
  • Unlike RL A, this instruction does not meaningfully affect any flags except C.
See Also
RLA, RLC, RR, SLA