[raspi-internals] Re: Update: Scalar Instructions
- From: Herman Hermitage <hermanhermitage@xxxxxxxxxxx>
- To: "raspi-internals@xxxxxxxxxxxxx" <raspi-internals@xxxxxxxxxxxxx>
- Date: Wed, 17 Jul 2013 23:08:00 +1200
> > I also had the problem that the descriptions of the instructions was
> often not complete (like which instructions affect which flags) I'll
> see if I can dig out my notes on that from somewhere.
>
> Those notes would be nice; Are there any non-comparison instructions
> which effect the flags?
Yes would be good to get this nailed. The docs have:
cmp, cmn, btst, and fcmp as setting flags (ignoring separate vector flags).
Phire was asking the other day about fcmp, I assume NaNs raise V flag for
unordered comparisons. I'm curious if there are some other SR bits for
rounding modes in fp.
Other ones are:
enable, disable, cbclr, cbinc, cbchg, cbdec, rti, pop.
It may not be intuitively obvious but according to the docs the following do
NOT modify the cc's
addcmpb<cc>, ror, lsl, lsr, asr
Be interesting what corrections we need to make.
Someone could double check against:
https://github.com/mgottschlag/vctools/blob/master/vcdb/_instructions.yaml
Cheers
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