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From: Al Johnston <sofeise@mindspring.com>
Subject: Re: gnat/ppc and a32 blt transfers
Date: Thu, 02 Nov 2000 14:58:36 -0500
Date: 2000-11-02T19:58:43+00:00	[thread overview]
Message-ID: <3A01C76C.86CEA181@mindspring.com> (raw)
In-Reply-To: 3A007357.FF3475A0@mindspring.com


In my case, atomic would be going the wrong way... the vme slave card
can not do any form of 64 bit transfers.

I tried to decode the assembly for this line of code causing the MBLT,
but
could not get anywhere... It probably doesn't matter.  the opcode access
the processor bus, which then goes across a pci bridge chip, and then
across a vme bridge chip.  It is this last chip that actually decides
that the transfer should be done as a MBLT.

Fortunately the vme bridge chip had a "no blt" bit which when set
caused the access to no longer be a MBLT, and more importantly,
to work!

I am not sure what to make of the "if you want to program in asm..."
remark....  All I was doing here was accessing memory...

-al



  parent reply	other threads:[~2000-11-02 19:58 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-11-01 19:47 gnat/ppc and a32 blt transfers Al Johnston
2000-11-01 20:52 ` Robert Dewar
2000-11-02  4:55   ` DuckE
2000-11-02 14:26     ` Robert A Duff
2000-11-02 19:58 ` Al Johnston [this message]
2000-11-04  5:02   ` Robert Dewar
2000-11-04  0:00     ` David Starner
2000-11-06  0:00       ` Robert Dewar
2000-11-11  6:38         ` David Thompson
2000-11-06  7:39       ` tmoran
2000-11-04  0:00     ` Al Johnston
2000-11-05  0:00       ` Florian Weimer
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