Abstract: In accordance with the invention, there are disposed a logical register group and a physical register group. Direct access is made to the logical register group on the basis of a register number designated by an instruction. To make access to the physical register group, there is disposed a circuit which converts the register number designated by the instruction to a physical register number.A plurality of arithmetical or logical operation units (ALUs) are disposed to execute a plurality of instructions in parallel. There is further disposed a circuit which supplies an operand data from the physical register group to each ALU and writes the operation result data of each ALU into the physical register group and into the logical register group.When a write register number designated by a preceding instruction A and a succeeding instruction B has the same value a, mutually different physical register numbers b' and b" are determined with respect to the write register number a for both instructions A and B.

Abstract: A semiconductor memory is provided with automatic refresh means including a timer, a refresh counter and a refresh buffer each formed on a semiconductor chip mounted with an asynchronous memory, for automatically performing a periodic refresh operation on the basis of a basic clock signal which is generated in response to the detection of a logical change in the output of the refresh counter. The automatic refresh counter includes means for performing one of a read operation and a write operation which are based upon a regular address signal asynchronous with the periodic refresh operation, in preference to the periodic refresh operation.

Abstract: In a serial-parallel A/D converter, at least two sets of comparators are provided for the conversion of the low-order bits and are operated in a cyclic fashion. Since the subsequent input can be subjected to the A/D conversion without waiting for the determination of the low-order bits, the conversion speed is increased.

Abstract: A semiconductor integrated circuit device has an address decoder which is constructed of a plurality of MOSFETs implemented in a switch tree. The switch tree includes first and second switch tree portions which are controlled `on` and `off` by the same input signals. A first switch branch in the first switch tree portion, which is constructed of a comparatively small number of MOSFETs, and a second switch branch in the second switch tree portion, which is constructed of a comparatively large number of MOSFETs, are controlled `one` and `off` by the same input signal, while a second switch branch in the first switch tree portion, which is constructed of a comparatively large number of MOSFETs, and a first switch branch in the second switch tree portion, which is constructed of a comparatively small number of MOSFETs, are controlled `on` and `off` by the same input signal.