A89: Documentation
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A89: Documentation
I either use an old book called
"M68000 16/32-bit microprocessor Programmer's Reference manual"
it is from 1984, and reprinted in 1986..
Or if that is not available (like i forgot it at home)
I use this pdf: ftp://alh.dhs.org/calculator/ti89/doc/68000UM.pdf
that I originally downloaded from motorola. (you can find it on their website,
but serching their web is a pain in the ass.)
//Olle
as for projects, I'm not working on anything right now..
Miles Raymond wrote:
>
> 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
References: