Systolic super summation device
First Claim
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1. A device for calculating sums of floating point summands, each summand including a characteristic and a mantissa, said device comprising:
- a sieve comprising a characteristic decode section for determining the value of the characteristic of each summand and a sieve section responsive to the determined characteristic of a summand for routing that summand toward an appropriate position at the output of said sieve corresponding to a fixed-point representation of said summand, said sieve including coalescence means for combining mantissas of different summands prior to said sieve output; and
accumulator means receiving and accumulating outputs from said sieve and converting the accumulated sum to floating point form, to thereby obtain a floating-point representation of each sum.
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Abstract
A cellular architecture for a systolic super summer for high throughput performance of repeated sums of floating-point numbers. The summer receives pipelined inputs of streams of summands, converts the floating-point summands into a fixed-point form by a sieve-like pipelined cellular network, and sums the emerging fixed-point numbers in a corresponding network of extremely long accumulators. The throughput per unit area of the hardware approaches that of a tree network, but without the long wires and signal propagation that are intrinsic to tree networks.
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19 Claims
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1. A device for calculating sums of floating point summands, each summand including a characteristic and a mantissa, said device comprising:
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a sieve comprising a characteristic decode section for determining the value of the characteristic of each summand and a sieve section responsive to the determined characteristic of a summand for routing that summand toward an appropriate position at the output of said sieve corresponding to a fixed-point representation of said summand, said sieve including coalescence means for combining mantissas of different summands prior to said sieve output; and accumulator means receiving and accumulating outputs from said sieve and converting the accumulated sum to floating point form, to thereby obtain a floating-point representation of each sum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A device for calculating sums of floating point summands, each summand including a characteristic and a mantissa, and for then calculating an iterative summation of a plurality of successive sums, said device comprising:
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a sieve comprising a characteristic decode section for determining the value of the characteristic of each summand and a sieve section responsive to the determined characteristic of a summand for routing that summand toward an appropriate position at the output of said sieve corresponding to a fixed-point representation of said summand, said sieve including coalescence means for combining mantissas of different summands prior to said sieve output; accumulator means receiving and accumulating outputs from said sieve and converting the accumulated sum to floating point form, to thereby obtain a floating-point representation of each sum, said accumulator means including a plurality of accumulators including a first accumulator α
0, a holding accumulator β
0 and at least one further accumulator;shifting means, upon entry into said first accumulator of a last summand mantissa in each of said successive sums, for shifting the contents of said first accumulator to said holding accumulator for summation with the contents of said holding accumulator, and upon entry into said holding accumulator of a last sum in said iterative summation, for shifting the contents of said holding accumulator to said at least one further accumulator for conversion to floating point form while said first accumulator and holding accumulator commence calculation of a further iterative summation. - View Dependent Claims (19)
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Specification