Re: zero runtime when negative

To: Dennis Ferguson <dennis.c.ferguson%gmail.com@localhost>
Subject: Re: zero runtime when negative
From: Matt Thomas <matt%3am-software.com@localhost>
Date: Tue, 26 Jun 2012 10:28:52 -0700

On Jun 26, 2012, at 9:50 AM, Dennis Ferguson wrote:

> The latter is a problem since many machines have no such counter
> in hardware, and for those that do the unlikely-to-roll hardware counter is
> often 64 bits wide and is a problem to sample with a 32 bit instruction set.

Really?  This hasn't been a problem on PowerPC with its 64-bit timebase.

the algorithm is simple

read upper
read lower
read upper again
compare upper values, if they differ do the again.

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- Re: zero runtime when negative
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- Re: zero runtime when negative
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  - From: Michael van Elst
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