Message-ID: <2FBE5CEB.BA7@impsat1.com.ar>
Date: Sat, 20 May 1995 18:19:39 -0300
From: Fernando Salas <fsalas AT impsat1 DOT com DOT ar>
MIME-Version: 1.0
To: djgpp AT delorie DOT com
Subject: Re: Funky asm startTimer block -- why the odd 'jmp' statements?
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Message-ID: <2FBE5BC1 DOT 1D1F AT impsat1 DOT com DOT ar>
Date: Sat, 20 May 1995 18:14:41 -0300
From: Fernando Salas <fsalas AT impsat1 DOT com DOT ar>
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To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Subject: Re: Funky asm startTimer block -- why the odd 'jmp' statements?
References: <Pine DOT SUN DOT 3 DOT 91 DOT 970518175708 DOT 16797P-100000 AT is>
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Eli Zaretskii wrote:
> 
> On Fri, 16 May 1997, Salvador Eduardo Tropea (SET) wrote:
> 
> > No that's a VERY OLD trick to access devices that aren't enough faster to
> > support 2 consecutive outs at the bus speed. In this case you are accessing to
> > the 8254 integrated in your motherboard so isn't necesary at all. Even more, as

> 
> A message was posted here a few days ago saying that similar code stopped
> working when the user upgraded to a Pentium.  So it might still be a good
> idea to wait a bit for the timer chip between two I/O instructions.

Someone correct me if I wrong but If I remember well those types of
jumps are also used to flush the CPU instruction cache when outs an ins
are involved because they cause some sort of problem. But I'm not sure
of it.

Fernando.