Shigeo Kuninobu

Design of high speed MOS multiplier and divider using redundant binary representation

A high speed multiplier and divider for MOS LSI based on a new algorithm is presented. When we implement the multiplier and the divider in LSI, the features such as high speed operation, small number of transistors and easy layout are the most important factors. A computational algorithm using a redundant binary representation has several excellent features such as high speed addition operations. We improved the algorithm and the method of implementation, and designed an advanced multiplier and divider with the above mentioned features. We expect mat our multiplier and divider are excellent compared with multipliers using the Booth algorithm and the Wallace tree, and with divider using the SRT method, respectively.

Accurate rounding scheme for the Newton-Raphson method using redundant binary representation

Proposes a new algorithm of estimation and compensation of the error effect for rounding in the case of implementation of division and square root using the Newton-Raphson method. The authors analyze the error of the hardware system to confirm the condition of the implementation with respect to this algorithm. Next, they describe in detail how to compensate the error by using this algorithm. Finally, they show that the hardware components for this algorithm, the direct rounding mechanism in the recode circuit and the sticky digit generating circuit, can be realized simply by improving the redundant binary representation multiplier. The number of increasing cycles for this new algorithm is only one, and the rounding result using this algorithm satisfies IEEE Standard 754 rounding perfectly. >

A partial scan design method based on n-fold line-up structures

We will present a partial scan design method based on n-fold line-up structures and a partial scan design method based on the state justification of pure FFs of load/hold type in order to achieve high fault efficiency for practical LSIs. We will also present a dynamic test sequence compaction method for acyclic structures. Experimental results for practical LSIs show that our presented methods can achieve high fault efficiency and reduce the number of test patterns by half.

A highly integrated 40-MIPS (peak) 64-b RISC microprocessor

A 1-million transistor 64-b microprocessor has been fabricated using 0.8- mu m double-metal CMOS technology. A 40-MIPS (million instructions per second) and 20-MFLOPS (million floating-point operations per second) peak performance at 40 MHz is realized by a self-clocked register file and two translation lookaside buffers (TLBs) with word-line transition detection circuits. The processor contains an integer unit based on the SPARC (scalable processor architecture) RISC (reduced instruction set computer) architecture, a floating-point unit (FPU) which executes IEEE-754 single- and double-precision floating-point operations a 6-KB three-way set-associative physical instruction cache, a 2-KB two-way set-associative physical data cache, a memory management unit that has two TLBs, and a bus control unit with an ECC (error-correcting code) circuit. >