Ethereal-dev: Re: [Ethereal-dev] Re: question on TLV

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From: "Guy Harris" <gharris@xxxxxxxxx>
Date: Tue, 13 Sep 2005 17:53:15 -0700 (PDT)
Graeme Hewson wrote:
> The S/370 Principles of Operation says the byte-oriented-operand feature
> is standard on System/370, implying what you say about S/360.

The S/360 POP:

    http://computer-refuge.org/bitsavers/ibm/360/A22-6821-0_360PrincOps.pdf

says

    Fixed-length fields, such as halfwords and double words, must be
located in main storage on an *integral boundary* for that unit of
information.

A "specification exception" occurs on an unaligned access.

A later edition:

    http://computer-refuge.org/bitsavers/ibm/360/A22-6821-7_360PrincOpsDec67.pdf

lists the "byte-oriented operand" option you mention, but notes that
"significant perfornace degradation is possible when storage operands are
not positioned at addresses that are integral multiples of the operand
length".