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Microprogram Self Assembler

IP.com Disclosure Number: IPCOM000075875D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Johnson, AM: AUTHOR

Abstract

The microprogram self-assembler (MSA) of Figs. 1 and 2 solves the problem of having too many microwords used in a coreload for the space available, either on the input media or in the reloadable control storage of the host processor. This problem is solved by using one byte (a word ID byte) to represent a control word (a control word may be four bytes or more), which produces at least a seventy-five percent reduction in control storage space required for the same program. The MSA can also be used to allow the customer coreload to be modified to include special microprogram strings.

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Microprogram Self Assembler

The microprogram self-assembler (MSA) of Figs. 1 and 2 solves the problem of having too many microwords used in a coreload for the space available, either on the input media or in the reloadable control storage of the host processor. This problem is solved by using one byte (a word ID byte) to represent a control word (a control word may be four bytes or more), which produces at least a seventy-five percent reduction in control storage space required for the same program. The MSA can also be used to allow the customer coreload to be modified to include special microprogram strings.

The MSA consists of four parts; word dictionary, scheme table, common field and microgenerator which are shown in Fig. 1. The word dictionary contains all the control words needed for generating microroutines.

The scheme table contains a pattern of words for defining each routine contained in the set to be self-assembled. A pattern has the following format: The first byte is the flag byte, which is used to define any

special operations to be performed on the pattern involved.

Examples of how the flags are used include: (1) specify

what is to be done with the microroutine after it has been

generated and the execute phase is entered, and (2) specify

how particular word types are to be modified within the

pattern.

The second byte is the count byte which is used to specify

the number of word ID bytes. A word ID byte specifies what

byte in the word dictionary is...