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Time to document behavior

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Jonathan Campbell
2015-05-31 21:28:40 -07:00
parent ec6bd40703
commit f83b276766
3 changed files with 14 additions and 0 deletions
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NOTES/Intel DIV behavior/Pentium 133MHz (1996) test results (1).txt.xz Executable file
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NOTES/Intel DIV behavior/README.TXT Normal file
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Collected here are "grind" dumps of the DIV instruction on various Intel processors.
Officially, DIV is not really supposed to modify any flags by Intel documentation.
But, at least on Pentium and lower processors, the flags do in fact change.
And in some cases, how these flags change can mean the difference between correct
and incorrect CPU detection by DOS programs (i.e. detecting the difference between
an Intel 386 vs a NexGen 5x86).
To preserve prior weird behavior, dumps of the DIV instruction's behavior are provided
here.

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NOTES/Intel DIV behavior/xzview.sh Executable file
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#!/bin/bash
xz -c -d "$1" | less -