STA

STA (short for "STore Accumulator") is the mnemonic for a machine language instruction which stores a copy of the byte held in the accumulator at the RAM or I/O address specified. The contents of the accumulator itself remains unchanged through the operation.

Addressing modes

Opcode		Addressing mode	Assembler format	Length in bytes	Number of cycles
Dec	Hex
141	8D	Absolute	STA nnnn	3	4
157	9D	Absolute,X	STA nnnn,X	3	5
153	99	Absolute,Y	STA nnnn,Y	3	5
133	85	Zeropage	STA nn	2	3
149	95	Zeropage,X	STA nn,X	2	4
129	81	Indexed-indirect	STA (nn,X)	2	6
145	91	Indirect-indexed	STA (nn),Y	2	6

STA supports the 7 different addressing modes 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

STA does not affect any of the CPU's status flags.