RLA

RLA is the mnemonic for the illegal opcode machine language instruction which rotates one bit left in memory then AND accumulator with memory.

This illegal opcode is a combination of two operations with the same addressing mode: ROL, AND.

Addressing modes

Opcode		Addressing mode	Assembler format	Length in bytes	Number of cycles
Dec	Hex
47	2F	Absolute	RLA nnnn	3	6
63	3F	Absolute,X	RLA nnnn,X	3	7
59	3B	Absolute,Y	RLA nnnn,Y	3	7
39	27	Zeropage	RLA nn	2	5
55	37	Zeropage,X	RLA nn,X	2	6
35	23	Indexed-indirect	RLA (nn,X)	2	8
51	33	Indirect-indexed	RLA (nn),Y	2	8

RLA supports 7 different addressing modes, as shown in the table at right. In the assembler formats listed, nn represents a single-byte (8-bit) figure, and nnnn is a two-byte (16-bit) address.

CPU flags

LAX affects 2 of the CPU's status flags:

• The negative flag is set if the result is negative, i.e. has it's most significant bit set.
• The zero flag is set if the result is zero, or cleared if it is non-zero.
• The carryflag is set according to left bit rotate.