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Zero Word Machine Instruction

IP.com Disclosure Number: IPCOM000048435D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Malik, WJ: AUTHOR

Abstract

In the IBM System/370, system code is frequently clearing fields in storage. This is usually done by the subtraction of a register from itself, then storing the register in a location.

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Zero Word Machine Instruction

In the IBM System/370, system code is frequently clearing fields in storage. This is usually done by the subtraction of a register from itself, then storing the register in a location.

A new System/370 instruction, "Zero Word", having the RX format, would set the full word at location D (B X ) to zero.

A problem with clearing a register, then storing it, forces an end to instruction pipelining (a degradation on high performance processors) and removes a register from the program which otherwise could contain an optimized variable (a general degradation to all PL/S programs, such as the major part of MVS).

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