A89: Re: Back to arrays... =(
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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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