Roman Hodek (Roman.Hodek@informatik.uni-erlangen.de)
Thu, 3 Sep 1998 10:44:50 +0200 (MET DST)
> Why sti() break other archs?
Because it resets the interrupt level to 0, which may be a different
level them before the accompanying cli. The i386 only has two
"levels", 0 and 1 (ints on and off), so that's no difference there.
But for example the m68k has int levels 0..7 (0=no int). During an
interrupt processing the IPL may be != 0, and if you simply do cli ...
sti then the level is 0 afterwards and more ints are allowed then
before. This may cause all kinds of havoc.
Roman
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