Browse Prior Art Database

Universal Mask Generator

IP.com Disclosure Number: IPCOM000042139D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Karim, FO: AUTHOR

Abstract

In certain data processing systems there are a great number of operations which in some way require masking. These masks differ in complexity and, if designed separately, could result in a huge number of circuits, complicated by a complex system of data flow paths and controls. The method of mask generation described herein generates all the masks required by the system, and also decreases circuitry while avoiding complexity. Any of these operations which require masking could use a number of specified masks under certain circumstances. The type of mask required will be generated by a specified field of the associated op-codes. These fields are the SH field with 5 bits, the RB field which addresses the last 6 bits of the RB-Register, and the Mask field which is 11 bits.

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Universal Mask Generator

In certain data processing systems there are a great number of operations which in some way require masking. These masks differ in complexity and, if designed separately, could result in a huge number of circuits, complicated by a complex system of data flow paths and controls. The method of mask generation described herein generates all the masks required by the system, and also decreases circuitry while avoiding complexity. Any of these operations which require masking could use a number of specified masks under certain circumstances. The type of mask required will be generated by a specified field of the associated op-codes. These fields are the SH field with 5 bits, the RB field which addresses the last 6 bits of the RB-Register, and the Mask field which is 11 bits. The types of masks required by a typical limited instruction set of the kind that requires a great deal of masking are: 1. a mask of 32 bits of 0's, 2. a mask of 32 bits of 1's, 3. a mask of N number of 1's followed by 32-N number of 0's, 4. a mask of N number of 0's followed by 32-N number of 1's, 5. a mask of 32-N number of 1's followed by N number of 0's, 6. a mask of 32-N number of 0's followed by N number of 1's, 7. a mask of only N'th position of 1, 8. a mask of 1's starting from N'th position through M'th position (this string of 1's will be surrounded by 0's), and 9. a mask of 0's starting from N'th position through M'th position (this string of 0's will be surrounded by 1's). The mask generator is designed as shown in Fig. 1. The fie...