From:	Peter DOT Henn AT t-online DOT de (Peter)
Newsgroups:	comp.os.msdos.djgpp,comp.sys.intel
Subject:	PCI read burst from CPU
Date:	22 Feb 1998 15:32:19 GMT
Organization:	T-Online
Lines:	26
Message-ID:	<6cpge4$m23$1@news01.btx.dtag.de>
Reply-To:	peter AT anywhere DOT de
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Hello PCI freaks,
I want to read the memory from a PCI adapter (e.g. Graphic card)
as fast as possible via PCI read bursts. Does there exist any
C or Assembler source?

Write burst no problem:
If I use the "_movedatal" from the "sys/movedata.h" of the DJGPP
package for PCI write transactions, I see PCI write bursts on a LA. 
The interface chip saves the address/data pairs and put them as
burst transaction on the PCI bus.
But this will not work during a read transfer, because the PCI
interface chip waits after sending the address to PCI bus until
it gets the target answer - the requested read data.

Problem read burst:
Possible there exist a way to use the CPUs cache to generate PCI
burst transfers. Naturally this requires a invalidation of the
cacheline before using them.

Please send hints and short code examples only to this newsgroup
and do not try my email.

Thanks & regards,
Peter

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