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Computer Provided With Storage Expansion and Adapted for Processing Paged Programs

IP.com Disclosure Number: IPCOM000080977D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Bouillot, M: AUTHOR

Abstract

This system enables the processing of a program structured in pages and modules in a computer provided with an address extension register. Pages and modules are located in partitions, the total of which does not exceed the addressing capacity of the words. A special register holds the identification of the partition containing the current page. Special instructions allow decoding of the page words, taking into account the contents of this register, and to modify the contents.

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Computer Provided With Storage Expansion and Adapted for Processing Paged Programs

This system enables the processing of a program structured in pages and modules in a computer provided with an address extension register. Pages and modules are located in partitions, the total of which does not exceed the addressing capacity of the words. A special register holds the identification of the partition containing the current page. Special instructions allow decoding of the page words, taking into account the contents of this register, and to modify the contents.

In many applications, programs are structured according to the paging system. Pages are constituted by lists of module addresses. The program execution is controlled by an "interpreter", i.e., a routine, the main functions of which consist in calling the modules and, after execution of a module, in determining the next step (for example: calling the immediately following module, stepping to another module, branching to another page, etc.). The address of the word identifying the module being executed is held in a register. In this description, it will be assumed that this register is one of the index registers of the computer, and it will be designated by XR1.

Difficulty arises when the number of bits required for addressing the memory exceeds the length of the words which constitute the pages. This situation occurs, in particular, when, due to storage expansion, the addressing is effected in association by an instruction register, the capacity of which is equal to the one of the data words, and an extension register. For example, in a known system, the data are arranged in 16-bit words, and the memory is divided into 5 partitions of 32,768 bits (i.e. 2/15/): - One "low" partition accessed by addresses 0 to 32 767; and

- Four "high" partitions accessed by addresses 32 768 to

65 535. The selection from those partitions

is effected by a 2-bit address extension

register, the contents of which...