res@cblpe.ATT.COM (Rob Stampfli) (12/10/87)
I have an AT&T PC6300 with a NEC V30 processor. When I run the Norton Utility program "si", it sometimes reports the processor chip as a V30, and sometimes (maybe 25% of the time) as a V20. Does anyone know how Norton decides what chip is being used? Has anyone else noticed this problem? Thanks, Rob Stampfli (cbosgd!cblpe!res)
jpp@slxsys.specialix.co.uk (John Pettitt) (12/16/87)
In article <707@cblpe.ATT.COM> res@cblpe.ATT.COM (55216-Rob Stampfli) writes: >I have an AT&T PC6300 with a NEC V30 processor. When I run the Norton Utility >program "si", it sometimes reports the processor chip as a V30, and sometimes >(maybe 25% of the time) as a V20. Does anyone know how Norton decides what >chip is being used? Has anyone else noticed this problem? I Don't know how SI does it but here is a good way to find out what CPU you have. 1) execute at least 30 identical short instructions - this ensures the prefetch Q is full. 2) Use self modifying code to change an instuction n bytes ahead to an inc or a flag clear or the like. 3) If the changed instruction is executed it was not in the Q decrement n and try again. 4) if the changed istruction was not executed that location had already been prefetched. Therefore the Q is n instructions. The Q on 80[88,86,188,186,286,386] is unique length for each chip. (Sorry I don't have the lengths). I goes without saying that interrupts must be disabled for correct operation. This method was, I believe, invented by Jude and Howie at Applied Reasoning Corp, Cambridge, Mass. -- John Pettitt - 144.5 MHz: G6KCQ, CIX: jpettitt, Voice: +44 1 398 9422 UUCP: ...uunet!mcvax!ukc!pyrltd!slxsys!jpp (jpp@slxsys.specialix.co.uk) Disclaimer: I don't even own a cat to share my views !