From Learn @ Cemetech
8-bit rotation to the left. The bit leaving on the left is copied into the carry, and to bit 0.
RLC A RLC B RLC C RLC D RLC E RLC H RLC L RLC (HL) RLC (IX+n) RLC (IY+n)
H and N flags are reset, P/V is parity, S and Z are modified by definition.
r denotes 8-bit register.