[A83] Re: HL = A * 12 (fast)
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[A83] Re: HL = A * 12 (fast)
I got ye beaten ;P Who does better?
ld l,a
add a,a ; *2
add a,l ; *3
ld l,a
ld h,0
add hl,hl ; *6
add hl,hl ; *12
----- Original Message -----
From: "Darren" <qarnos@dingoblue.net.au>
To: <assembly-83@lists.ticalc.org>
Sent: Wednesday, April 24, 2002 7:35 AM
Subject: [A83] HL = A * 12 (fast)
>
>
> I wrote this little piece of code to calculate HL = A * 12. It seems to
> be a bit faster than anything else I could find, so maybe some of you
> could benefit from it, or prove me wrong! :)
>
> It takes 46 T-states, and destroys A:
>
> add a, a ; A * 2
> ld l, a
> add a, a ; A * 4
> add a, l ; A * 6
> ld l, a
> sbc a, a
> and 1
> ld h, a
> add hl, hl ; A * 12
>
>
>
>
>
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