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Combining Flip Latch Level Micro Sequential Logic Blocks

IP.com Disclosure Number: IPCOM000088806D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Reddi, UP: AUTHOR

Abstract

Micro-sequential logic blocks are combined into one functional macro block by performing the following steps: a. Find the input and output nets of the logic function to be combined. b. Find the latch forming the feedback blocks. c. Combine these latch blocks into one block with input nets and output nets as found in step a. In order to perform step a, the following sequence must be followed: 1) Pickup and process the element in a feedback path and check to see whether it is a functional input. If it is a functional input, then this not will be an input to the combined block, and steps 2 through 6 described below are skipped. 2) If the net is a functional output, then it will be an output to the combined block, and steps 7 through 9 described below are skipped.

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Combining Flip Latch Level Micro Sequential Logic Blocks

Micro-sequential logic blocks are combined into one functional macro block by performing the following steps: a. Find the input and output nets of the logic function to be combined. b. Find the latch forming the feedback blocks. c. Combine these latch blocks into one block with input nets and output nets as found in step a. In order to perform step a, the following sequence must be followed: 1) Pickup and process the element in a feedback path and check to see whether it is a functional input. If it is a functional input, then this not will be an input to the combined block, and steps 2 through 6 described below are skipped.
2) If the net is a functional output, then it will be an output to the combined block, and steps 7 through 9 described below are skipped. 3) Find all of the sources for the logic block whose output is the same as the feedback element. 4) Pick up an unprocessed source net, and check whether it is a functional input. If it is a functional input, then this net will be an input to the combined block, and step 5 is skipped. 5) Check whether the source net is equal to one of the feedback elements in the same feedback path. If it is not, then this net will be an input net to the combined block. 6) Go to 4 for each unprocessed source net. Find the number of sinks for the feedback element, and check whether there is more than one sink. If the number of sinks is one or less, then steps 8 through 9 are skipped. 7) Find all of the sinks for the feedback element. 8) Pick up an unprocessed sink net, and check whether it is an element of the same feedback path. If it is not, then this net will be an output net to the combined block. Repeat this procedure for all of the sink nets. 9) Go to 1 for each unprocessed feedback element....