Opcodes

z80 » Opcodes

You're lucky: The z80 microprocessor has one of the shortest instruction sets of operation codes! That means you don't have to memorize thousands upon thousands of individual commands. There are only 677 commands for the z80, that's not much when you consider the thousands for the Intel's 8080.

An opcode is an instruction.

	ld hl,xxxx
	out (x),a
	cp xx

These are just a few examples. Each opcode is actually one or more bytes that tell the z80 what to do. The processor doesn't see cp (hl) or ld a,b but instead sees $be and $78 respectively. The z80 performs the operation assigned to that byte value.

For call xxxx, the processor will see $cd. Once it sees that value, it knows it has to use the next two consecutive bytes in memory for the address to call.

So, when you type the code...

	call $1234
	ld hl,$ff
	cp b

The z80 sees...

	cd3412
	21ff00
	b8

Do you want to view the list of z80 standard operation codes organized by byte value or in alphabetical order?

You can also check out a full listing of z80 opcodes with clock cycles and flag effects: z80.txt.

More from z80 » Opcodes
Opcodes // Opcodes Sorted By Value // Opcodes Sorted By Name