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Index > Heap > 8086 (88) behavior on invalid instruction ?

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Ninho



Joined: 07 May 2010
Posts: 16
Ninho
Hi All! As I don't have an old 8086 based machine to check the behavior with, can someone assert either from experiment or own experience or litterature, what happens exactly when the original Intel 8086/8088 is fed an invalid instruction? Since those processors didn't have the software exception, I can guess they would either reset themselves, either just stall until being externally reset (maybe outputting a special cycle indication on the bus)... but searching the web couldn't find a definitive answer.



TIA

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Ninho
Post 07 May 2010, 10:01
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MazeGen



Joined: 06 Oct 2003
Posts: 975
Location: Czechoslovakia
MazeGen
Post 07 May 2010, 12:12
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Ninho



Joined: 07 May 2010
Posts: 16
Ninho
Thanks for the link, Mazegen, except what's it good for ? - alright, the queries are similar, certainly not answered in that thread unfortunately Sad

Is it your own post in that thread you meant to refer me to ? But that's particularly irrelevant...


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Ninho
Post 07 May 2010, 14:28
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MazeGen



Joined: 06 Oct 2003
Posts: 975
Location: Czechoslovakia
MazeGen
I just wanted to let you know that there was the same question not a long time ago. Well, it doesn't answer it clearly, erm... you right.
Post 07 May 2010, 14:46
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Ninho



Joined: 07 May 2010
Posts: 16
Ninho
MazeGen wrote:
I just wanted to let you know that there was the same question not a long time ago. Well, it doesn't answer it clearly, erm... you right.


Indeed it is surprising me that the previous thread you brought to my attention has remained unanswered. I well know, if I had access to an 8086 it wouldn't be 5 minutes before I had a ready answer ; just fire 'debug', have it execute some illegal code like "FF FF" and see what happens...

Unfortunately in this circumstance, my first PC was a 80286 AT. Before that I had been programming mainframes, not microprocessors - oh, wait, old memory coming back I /did/ some 6502 assembler programming (Apple II). But certainly /never/ came near an 8086 or 8088 Sad

Hopefully on /this/ forum, there are people who can answer the question in title! Come on, guys !
Post 07 May 2010, 21:37
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Tyler



Joined: 19 Nov 2009
Posts: 1216
Location: NC, USA
Tyler
You could ask this guy.
Post 07 May 2010, 21:55
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Ninho



Joined: 07 May 2010
Posts: 16
Ninho
Tyler wrote:
You could ask this guy.


This would be the man who wanted to
Quote:
run Flat Assembler on a emulated IBM PC/XT
, right ? Uh, sure ... could ask him as well as anybody else ;=)
Post 08 May 2010, 16:24
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Tyler



Joined: 19 Nov 2009
Posts: 1216
Location: NC, USA
Tyler
Embarassed Sorry, I assumed he got his 8086/8088(as the "(was 'Processor Needed')" would suggest). I need to read things...

You could buy one. I don't know reliable it is, but apparently http://us.ebid.net/for-sale/intel-p8086-2-8086-8mhz-cpu-processor-chip-8643937.htm?from=googlebase has 12(sold as is Wink).
Post 08 May 2010, 19:37
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