“ByteByteJump”, Esolang Wiki (computability; backlinks)⁠:

ByteByteJump is an extremely simple One Instruction Set Computer (OISC). Its single instruction copies 1 byte from a memory location to another, and then performs an unconditional jump.

An instruction consists of 3 addresses stored consecutively in memory:

A, B, C

A is the source address, B is the destination address, and C is the jump address. N.B: ByteByteJump uses byte addressing.

ByteByteJump has no ALU, but arithmetic operations and conditional jumps can still be performed by using self-modifying code and lookup tables (see Example). Despite its apparent simplicity, ByteByteJump actually belongs to the computational class of real microprocessors: the Linear bounded automaton.

WordWordJump is the larger family of machines to which ByteByteJump belongs. An X×Y-bit WordWordJump machine has Y-bit data words and X×Y-bit address words, where X must be ≥2 for the machine to be able to compute. The optimal value for X (as explained here) seems to be 3.

ByteByte/Jump is ByteByteJump’s sister machine. It splits the single instruction of ByteByteJump into two for improved code density.

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