Embodiments of the present disclosure pertain to multimodal digital multiplier circuits and methods. In one embodiment, partial product outputs of digital multiplication circuits are selectively inverted based on a mode control signal. The mode control signal may be set based on a format of the operands input to the multiplier. Example embodiments of the disclosure may multiply combinations of signed and unsigned input operands using different modes.

An apparatus and method for efficiently performing a multiply add or multiply accumulate operation. For example, one embodiment of a processor comprises: a decoder to decode an instruction specifying an operation, the instruction comprising a first operand identifying a multiplier and a second operand identifying a multiplicand; and fused multiply-add (FMA) execution circuitry comprising first multiplication circuitry to perform a multiplication using the multiplicand and multiplier to generate a result for multipliers and multiplicands falling within a first precision range, and second multiplication circuitry to be used instead of the first multiplication circuitry for multipliers and multiplicands falling within a second precision range.

Accumulator hardware logic includes first and second addition logic units and a store. The first addition logic unit comprises a first input, a second input and an output, each of the first and second inputs arranged to receive an input value in each clock cycle. The second addition logic unit comprises a first input that is connected directly to the output of the first addition logic unit. It also comprises a second input and an output. The store is arranged to store a result output by the second addition logic unit. The accumulator hardware logic further comprises shifting hardware and/or negation hardware positioned in a feedback path between the store and the second input of the second addition logic unit. The shifting hardware is configured to perform a shift by a fixed number of bit positions in a fixed direction.

A MAC operator includes a plurality of multipliers configured to perform a multiplication operation on a floating-point format first data and a floating-point format second data to output a floating-point format multiplication result data, a plurality of floating-point-to-fixed-point converters configured to receive the floating-point format multiplication result data from each of the plurality of multipliers and convert into a fixed-point format multiplication result data to be output, and an adder tree configured to perform an addition operation on the fixed-point format multiplication result data that is output from the plurality of floating-point-to-fixed-point converters. If a first mantissa of the first data and a second mantissa of the second data are composed of M-bit (M being a natural number), each of the plurality of multipliers is configured to perform the multiplication operation so that the fixed-point format multiplication result data includes a mantissa of 2*(M+1) bits.

A neural network system includes a data type converter and a MAC operator. The data type converter may convert 32-bit floating-point format into one of a plurality of 16-bit floating-point formats. The MAC operator may perform MAC operations using 16-bit floating-point format data converted by the data type converter. The MAC operator includes a data type modulator configured to modulate the bit number of the converted 16-bit floating-point format to provide a modulated floating-point format with bit number different from the bit number of the converted 16-bit floating-point format.

A MAC operator includes a plurality of multipliers, a plurality of floating-point to fixed-point converters, an adder tree, an accumulator, and a fixed-point to floating-point converter. Each of the plurality of multipliers may perform a multiplication operation on first data and second data of a single-precision floating-point (FP32) format to output multiplication result data of the FP 32 format. Each of the plurality of floating-point to fixed-point converters may convert the FP 32 format into a fixed-point format. The adder tree may perform a first addition operation on the data of the fixed-point format. The accumulator may perform an accumulation operation on the data output from the adder tree. And the fixed-point to floating-point converter may convert the data of the fixed-point format into data of the FP32 format.

A MAC operator includes a plurality of multipliers, a plurality of floating-point to fixed-point converters, and an adder tree. Each of the plurality of multipliers may perform a multiplication operation on first data and second data of a floating-point format to output multiplication result data. Each of the plurality of floating-point to fixed-point converters may convert the data type of the multiplication result data into a fixed-point format. The adder tree may perform a first addition operation on the multiplication result data of the fixed-point format. Each of the plurality of floating-point to fixed-point converters may skip a +1 operation for processing a negative number and a +1 operation for roundup processing in a data type converting process, and output round bits equaling to bit values not added by the skipped +1 operations in the data type converting process.

A MAC operator includes a plurality of data type converters and a plurality of multipliers. Each of the plurality of data type converters may receive 16-bit input data of one of first to fourth data types of a floating-point format to convert into L-bit output data of the floating-point format. Each of the plurality of multipliers may perform a multiplication on the L-bit output data of the floating-point format outputted from two of the plurality of data type converters to output multiplication result data of the floating-point format.

Embodiments of the present disclosure pertain to multimodal digital multiplier circuits and methods. In one embodiment, partial product outputs of digital multiplication circuits are selectively inverted based on a mode control signal. The mode control signal may be set based on a format of the operands input to the multiplier. Example embodiments of the disclosure may multiply combinations of signed and unsigned input operands using different modes.

An apparatus and method for efficiently performing a multiply add or multiply accumulate operation. For example, one embodiment of a processor comprises: a decoder to decode an instruction specifying an operation, the instruction comprising a first operand identifying a multiplier and a second operand identifying a multiplicand; and fused multiply-add (FMA) execution circuitry comprising first multiplication circuitry to perform a multiplication using the multiplicand and multiplier to generate a result for multipliers and multiplicands falling within a first precision range, and second multiplication circuitry to be used instead of the first multiplication circuitry for multipliers and multiplicands falling within a second precision range.