An instruction set where each field (a bit or group of bits) in an instruction word controls some functional unit or gate directly, as opposed to {vertical encoDINg} where instruction fields are decoded (by hard-wiredlogic or microcode) to produce the control signals. Horizontal encoDINg allows all possible combinations of control signals (and therefore operations) to be expressed as instructions whereas vertical encoDINg uses a shorter instruction word but can only encode those combinations of operations built into the decoDINg logic. An instruction set may use a mixture of horizontal and vertical encoDINg within each instruction. Because an architecture using horizontal encoDINg typically requires more instruction word bits it is sometimes known as a {very long instruction word} (VLIW) architecture. (1995-04-23)