Date   : Tue, 09 Mar 2004 11:56:48 +0000
From   : Richard_Talbot-Watkins@...
Subject: Re: CLI then SEI

tom@... wrote:

> But on a real BBC, it seems there's some kind of pipelining-like
> behaviour going on. After a bit of playing around, I found that
> the interrupt doesn't happen until after the instruction
> following the CLI has run! So a CLI/SEI pair won't cause an
> infinite chain of interrupts, though a CLI/NOP/SEI will. (The
> address on the stack on entry to the IRQ routine is the
> instruction after the instruction after the CLI.)

Well spotted Tom!  This doesn't seem to be mentioned anywhere official, but
it looks as if other people have noticed it too:

http://www.softwolves.pp.se/misc/arkiv/cbm-hackers/5/5677.html

Rich



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