[comp.sys.intel] <none>

sam2y@batik.cs.Virginia.EDU (Steven A. Moyer) (12/20/90)

I'm looking for information concerning how cache lines are filled on the
i860 processor.  In particular, does the i860 make use of the NA# signal
(assuming it is support by the memory subsystem) in order to pipeline
cache line reads?

In measuring load rates on an RX node, I can obtain a rate of 20M/sec
using the pfld instruction.  With the cache flushed so that there is
no write-back, I can only obtain a rate of 10M/sec using the fld
instruction.  Yet, the hardware reference manual seems to imply that the
cache controler does indeed take advantage of memory pipelining when
available.

Any ideas?


+--------------------------------------------------------------------+
| Steven Moyer                   |       THIS SPACE FOR RENT         |
| University of Virginia         |                                   |
|                                | "Just a rebel without a clue..."  |
| E-mail: sam2y@virginia.edu     |                - The Replacements |
+--------------------------------------------------------------------+

wpd@ece.arizona.edu (William P. Delaney) (06/29/91)

I seem to recall hearing about an undocumented instruction in
protected mode x86 processors called LOADALL, or something like
that.  Does anyone have any technical information on this?  I
would be interested in the following details in particular:

	* opcode value(s)
	* precise effects
	* inverse operation (i.e. SAVEALL?)

Thanks,
Bill Delaney (wpd@ece.arizona.edu)