[E3-hacking] [RFC][PATCH v2 1/5] omap1: Amstrad Delta: add FIQ handler for serial keyboard port interrupt processing

Ralph Corderoy ralph at inputplus.co.uk
Tue Mar 30 20:06:57 EDT 2010


Hi Janusz,

> And thanks for pushing me into reading the ARM Assembly Language book,
> so I would be able to do more than just understanding and copy-pasting
> the code ;).

It's a lovely instruction set compared to many others.

> > > +state:
> > > +	ldr r10, [r9,#FIQ_STATE]
> > > +	cmp r10, #0				@ are we expecting start bit?
> > > +	bne data				@ no - in data processing state
> >
> > Similarly, an `ldrs' here would make the cmp redundant.
> 
> I'm not sure if the S suffix is also valid for memory transfer
> instructions

No, you're correct.  Memory transfers can't do the "set ALU flags"
S-bit.  Sorry to mislead.

Cheers,
Ralph.




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