A89: Re: Re: Back to arrays... =(
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A89: Re: Re: Back to arrays... =(
Hehe, another question? =)
Where do you get the info on the timing of each op code and register access
and all?
-Miles Raymond EML: m_rayman@bigfoot.com
ICQ: 13217756 IRC: Killer2 AIM: KilIer2 (kilier2)
http://www.bigfoot.com/~m_rayman/
----- Original Message -----
From: Zoltan Kocsi <zoltan@bendor.com.au>
To: <assembly-89@lists.ticalc.org>
Sent: Wednesday, July 28, 1999 2:37 AM
Subject: A89: Re: Back to arrays... =(
> > Now, one more question: Is the 'array+2' meathod better than the
'2(a6)'
> > meathod? It is faster on the calc since it doesn't have to add it
while
> > running, correct?
>
> Actually, no. The n(ax) form has an extension word which contains the
> offset. It is one word. The absolute address is stored in 2 extension
> words. On the 68000 reading a word from memory takes 4 clock cycles (min).
> Therefore, reading the instruction itself is 4 clocks more in case of
> the absolute addres version. The penalty that you pay for the adding
> in the n(ax) addressing mode is IIRC 2 clocks (I don't have the 68000
> insn timing handy now). All in all, you are 2 clocks and 1 word better
> off using the register. Of course, you had to load that register but if
> you use the address often, then it definitelly worth to use a register.
>
> Regards,
>
> Zoltan
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