Sambanova Systems, Inc.

Matthew M Kim

Vojin G Oklobdzija

A floating-point accumulator circuit includes a floating-point input having an input significand field and a first shifter coupled to the input significand field and providing an output of the input significand field shifted by a first amount. A carry-save adder has a first, second, and third input and an output. The first input is coupled to the output of the first shifter and the output provides carry bits and sum bits representing a summation of the first input, the second input, and the third input as a significand of the accumulated value. Shifters are also coupled to the carry bits and the sum bits of the output of the carry-save adder to respectively provide the carry bits and the sum bits, both shifted by a second amount, to the second input and the third input of the carry-save adder.

Floating point accumulater with a single layer of shifters in the significand feedback

A floating-point accumulator circuit includes an addend input register having an addend exponent and an addend significand and an accumulation register with a first portion to hold a representation of an accumulation exponent and a second portion to hold a representation of an accumulation significand. A control circuit is also included to generate an accumulator zero control signal and an addend zero control signal based on the addend exponent and the accumulation exponent. It also includes an adder circuit with an output an input of the accumulation register. A first zeroing circuit sends either a zero or a value based on the addend significand to a first input of the adder circuit based on the addend zero control signal, and a second zeroing circuit sends either zeros or a value based on the accumulator significand to a second input of the adder circuit, based on the accumulator zero control signal.

Floating-point accumulator

A Floating point Multiply-Add, Accumulate Unit, supporting BF16 format for Multiply-Accumulate operations, and FP32 Single-Precision Addition complying with the IEEE 754 Standard is described with exception handling. Operations including exception handling in a way that does not interfere with execution of data flow operations, overflow detection, zero detection and sign extension are adopted for 2's complement and Carry-Save format.

Floating point multiply-add, accumulate unit with exception processing

Floating point Multiply-Add, Accumulate Unit, supporting BF16 format for Multiply-Accumulate operations, and FP32 Single-Precision Addition complying with the IEEE 754 Standard. The Multiply-Accumulate unit uses higher radix and longer internal 2's complement significand representation to facilitate precision as well as comparison and operation with negative numbers. The addition is performed using Carry-Save format to avoid long carry propagation and speed up the operation. Operations including overflow detection, zero detection and sign extension are adopted for 2s complement and Carry-Save format. Handling of Overflow and Sign Extension allows for fast operation relatively independent on the size of the accumulator.

Floating point multiply-add, accumulate unit with carry-save accumulator

Floating point Multiply-Add, Accumulate Unit, supporting BF16 format for Multiply-Accumulate operations, and FP32 Single-Precision Addition complying with the IEEE 754 Standard. The Multiply-Accumulate unit uses higher radix and longer internal 2's complement significand representation to facilitate precision as well as comparison and operation with negative numbers. The addition can be performed using Carry-Save format to avoid long carry propagation and speed up the operation. The circuit uses early exponent comparison to shorten the accumulate pipeline stage. Operations including overflow detection, zero detection and sign extension are adopted for 2s complement and Carry-Save format.

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Frankston South, Australia

Matthew M Kim