STX

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

Addressing modes

Opcode		Addressing mode	Assembler format	Length in bytes	Number of cycles
Dec	Hex
142	8E	Absolute	STX nnnn	3	4
134	86	Zeropage	STX nn	2	3
150	96	Zeropage,Y	STX nn,Y	2	4

STX supports 3 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

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