Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!necntc!ames!sdcsvax!ucsdhub!esosun!seismo!uunet!mcvax!hafro!krafla!frisk
From: frisk@krafla.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: NOP
Message-ID: <16@krafla.UUCP>
Date: Tue, 29-Sep-87 14:03:12 EDT
Article-I.D.: krafla.16
Posted: Tue Sep 29 14:03:12 1987
Date-Received: Sat, 3-Oct-87 04:58:16 EDT
References: <2306@sphinx.uchicago.edu> <4478@amd.AMD.COM> <6375@ut-ngp.UUCP>
Reply-To: frisk@krafla.UUCP (Fridrik Skulason)
Organization: University of Iceland (RHI)
Lines: 21
Keywords: NOP

>In article <4478@amd.AMD.COM> ching@amd.UUCP (Mike Ching) writes:
>
>Actually, I thought that NOPs did an OR of the AX register on itself (or some
>similar operation that causes no change to data.)  As such, they DO affect the
>execution time involved.

>Could someone knowledgeable confirm or refute this?

The NOP operation is really XCHG AX,AX  and takes just as long to execute
as XGHG AX,BX (3 clock cycles).

This - however - is less than the instruction fetch time.
.
.
.

-- 
         Fridrik Skulason          University of Iceland
         UUCP  frisk@rhi.uucp      BIX  frisk

     This line intentionally left blank ...................