Michael,

On Wed, 26 Jan 2005 06:48:05 -0600, michael brown wrote:

> > >     movlw    (1<<FLAG_Happy)|(1<<FLAG_Sleepy)|(1<<FLAG_Doc)
> > >     iorwf    FLAGS,f
> >
> > I can't for the life of me see what you're doing with this one (I must
> be getting old! :-) - care to explain?
> 
> He's setting up a bit mask.
>...<

Ah!  Thanks for that - it's a Demon Tweak that I'd only seen a couple of times and hadn't understood before...

> The assembler will build a literal that consists of a 1 left shifted 4
> bits (0x10) AND'd with a 1 left shifted 1 bit (0x02) AND'd with a 1 left
> shifted 0 bits (0x01) resulting in a literal with a value of 0x13.  This
> is a clever way to help make the program oblivious to absolute bit
> positions within the registers assigned to ports. 

...and oblivious to this reader without an explanation - I am getting old, I'm sure :-(

> This way you only
> have to change the EQU to change pin assignments, and then recompile.
> The assembler will fix the movlw automatically.

Got it - thanks muchly!

Cheers,



Howard Winter
St.Albans, England


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