Orthogonal instruction set
<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.
