< architecture > An instruction set where all (or most) instructions have the same format and all registers and addressing modes can be used interchangeably - the choices of op code , register, and addressing mode are mutually independent (loosely speaking, the choices are " orthogonal "). This contrasts with some early Intel microprocessors where only certain registers could be used by certain instructions.
Examples include the PDP-11 , 680x0 , ARM , VAX .
(2002-06-26)