Browse Prior Art Database

Two Way Mapping Device

IP.com Disclosure Number: IPCOM000090164D
Original Publication Date: 1969-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Ashany, A: AUTHOR [+5]

Abstract

The device is for two-way mapping between two sets of variables that are designated A and B. An application for the device is mapping between a set of A addresses used by a CPU and a set of B addresses used by peripheral equipment. In the example, there are four different addresses in each set designated by 0...3.

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Two Way Mapping Device

The device is for two-way mapping between two sets of variables that are designated A and B. An application for the device is mapping between a set of A addresses used by a CPU and a set of B addresses used by peripheral equipment. In the example, there are four different addresses in each set designated by 0...3.

An A address is applied through Or 2 to memory 3. The latter includes an address decoding circuit that selects one of the four words in the memory according to the input address. Each word of memory 3 stores the B address and associated data for the A address. For example, the A address A2 selects a word that contains the B address B0 and associated control data D0. The B address and the associated data appear at output 4 that is applied to the selected peripheral device.

The B address is applied through Or 5 to memory 6 in which the A address is stored in locations that are selected from the associated B address. In the example, address B0 is decoded to select the memory word holding the address A2. This address is supplied to the CPU at output 7. The output of memory 6 is also applied through Or 2 to read the data associated with the B address. The data is supplied to the CPU at output 8.

A connection is provided to transmit the B field of the memory 3 to Or 5 to address memory 6 for changing the map.

The function of the memories 3 and 4 can be combined in a single four-word memory having the A, B, and D fields in each word. An...