The University of Texas System

Crossfield Technology LLC

Earl Swartzlander

Lauren Guckert

Jongwook Sohn

Jordan Hani Saleh

Hani Saleh

Memristor-based dividers using memristors-as-drivers (MAD) gates. As a result of employing MAD gates in memristor-based dividers, such as binary non-restoring dividers and SRT dividers, the number of delay steps may be less than half than the number of delay steps required in traditional CMOS implementations of dividers. Furthermore, by using MAD gates, memristor-based dividers can be implemented with less complexity (e.g., fewer memristors and drivers). As a result, by the memristor-based dividers using MAD gates, the speed and complexity of a wide variety of arithmetic operations is improved.

Memristor-based dividers using memristors-as-drivers (MAD) gates

Memristor-based multipliers using memristors-as-drivers (MAD) gates. As a result of employing MAD gates in memristor-based multipliers, such as shift-and-add multipliers, Booth multipliers and array multipliers, the number of delay steps may be less than half than the number of delay steps required in traditional CMOS implementations of multipliers. Furthermore, by using MAD gates, memristor-based multipliers can be implemented with less complexity (e.g., fewer memristors and drivers). As a result, by the memristor-based multipliers using MAD gates, the speed and complexity of a wide variety of arithmetic operations is improved.

Memristor-based multipliers using memristors-as-drivers (MAD) gates

A new lower-power gate design for memristor-based Boolean operations. Such a design offers a uniform cell that is configurable to perform all Boolean operations, including the XOR operation. For example, a circuit to perform the AND operation utilizes a first memristor and a second memristor connected in series. The circuit further includes a switch, where a node of the second memristor is connected to the switch. Furthermore, the circuit includes a third memristor connected to the switch in series, where the switch and the third memristor are connected in parallel to the first and second memristors. Additionally, the first voltage source is connected to the first memristor via a first resistor. In addition, a second voltage source is connected in series to the switch and the third memristor. In such a design, the delay is reduced to a single step and the area is reduced to at most 3 memristors.

Memristor logic design using driver circuitry

Memristor-based adders using memristors-as-drivers (MAD) gates. As a result of employing MAD gates in memristor-based adders, such as ripple carry adders, carry select adders, conditional sum adders and carry lookahead adders, the number of delay steps may be less than half than the number of delay steps required in traditional CMOS implementations of adders. Furthermore, by using MAD gates, memristor-based adders can be implemented with less complexity (e.g., fewer memristors and drivers). As a result, by the memristor-based adders using MAD gates, the speed and complexity of a wide variety of arithmetic operations is improved.

Memristor-based adders using memristors-as-drivers (MAD) gates

A fused floating-point dot product unit. The fused dot product unit includes an improved alignment scheme that generates smaller significand pairs compared to the traditional alignment due to the reduced shift amount and sticky logic. Furthermore, the fused dot product unit implements early normalization and a fast rounding scheme. By normalizing the significands prior to the significand addition, the length of the adder can be reduced and the round logic can be performed in parallel. Additionally, the fused dot product unit implements a four-input leading zero anticipation unit thereby reducing the overhead of the reduction tree by encoding the four inputs at once. The fused floating-point dot product unit may also employ a dual-path (a far path and a close path) algorithm to improve performance. Pipelining may also be applied to the dual-path fused dot product unit to increase the throughput.

Dual-path fused floating-point two-term dot product unit

In an embodiment, a dot-product unit to perform single-precision floating-point product and addition operations is disclosed that includes a first multiplier tree unit adapted to multiply first and second significand operands to produce a first set of two partial products. The dot-product unit further includes a second multiplier tree unit adapted to multiply third and fourth significand operands to produce a second set of two partial products, a shared exponent compare unit adapted to compare exponents of the first, second, third and fourth operands to produce an alignment shift value, and an alignment unit adapted to shift the second set of two partial products based on the alignment shift value. The dot-product unit also includes an adder unit adapted to add or subtract the first set of two partial products and the second shifted set of two partial products to produce a dot-product value that is a single-precision floating-point value.

Floating-point fused dot-product unit

In a particular embodiment, a method is disclosed that includes receiving first and second operands at a floating-point fused add-subtract circuit. The method further includes simultaneously performing add and subtract operations on the first and second operands via the floating-point fused add-subtract circuit to produce a sum result output and a difference result output. The floating-point fused add-subtract circuit includes sign logic, exponent adjustment logic, and shift logic that are shared by an add/round and post-normalize circuit and a subtract/round and post-normalize circuit to produce the sum and difference result outputs.

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Austin, TX, United States of America

Earl Swartzlander