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Extended Array Logic

IP.com Disclosure Number: IPCOM000085150D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Cook, PW: AUTHOR [+2]

Abstract

Described is a technique of subdividing a wide logic array into a group of narrow subarrays, in such a manner that corresponding word lines in adjacent subarrays may be joined together to form, where needed, a wide word as if selected from the original wide word array (or section thereof) while retaining, where the function permits, the high-gate utilization of narrow arrays. Some examples of typical array implementations are set forth in logic notation as follows: 1) For SEL = 01 C(1) = A(1) ^ B(1) C(2) = A(2) ^ B(2) C(3) = A(3) ^ B(3) C(4) = A(4) ^ B(4) 2) For SEL = 10 A(z) = (A(1) U A(2) U A(3) U A(4)) (Image Omitted)

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Extended Array Logic

Described is a technique of subdividing a wide logic array into a group of narrow subarrays, in such a manner that corresponding word lines in adjacent subarrays may be joined together to form, where needed, a wide word as if selected from the original wide word array (or section thereof) while retaining, where the function permits, the high-gate utilization of narrow arrays. Some examples of typical array implementations are set forth in logic notation as follows: 1) For SEL = 01

C(1) = A(1) ^ B(1)

C(2) = A(2) ^ B(2)

C(3) = A(3) ^ B(3)

C(4) = A(4) ^ B(4)

2) For SEL = 10

A(z) = (A(1) U A(2) U A(3) U A(4))

(Image Omitted)

This corresponds to (2 devices per word input, 1 device per word output): (10 x 2 + 5) x 5 = 125 devices.

The array is divided into two sections as shown:

(Image Omitted)

This requires:

[ (6 + 6) x 2 + 2 + 3 ] x 3 = 87 devices. The array may be divided into four sections: SEL A(1) B(1) C(1) SEL A(2) B(2) C(2) SEL A(3) B(3) C(3) SEL A(4) B(4) C(4) A(z) 01 1 1 1 01 1 1 1 0l 1 1 1 01 1 1 1 10 0 * 0 * 0 * 0 1 which requires; (16 x 2 + 5) x 2 = 74 devices.

The above examples show subarray words either completely independent or completely joined. Intermediates are also possible, as the joining of any adjacent words in the subarrays is independent from any other array feature. This "half- word" (with respect to the original wide array) functions are easily formed.

For a specific large array which performed addition and logical functions, the array had 154 devices/word and 231 words, for a total of 35,600 devices. If the array is divided into 8 identical s...