Adam Wozniak <[EMAIL PROTECTED]> wrote:
> Florent Pillet wrote:
>
> > I'm trying to determine the memory bus width on various Palm models, to be
> > able to optimize large data transfers (i.e. using move.w or move.l
> > instructions) but did not find any information about it.
> >
> > Anybody knows where I can get this information?
>
> Poking at the registers on my MC68328 based Palm VII tells me the bus
> is 16 bits wide. Poking through the manual for the MC68EZ328 tells me
> that you have two choices; 8-bit or 16-bit. I suspect wide moves are the
> best you'll get.
Seems to me that using the move.l instruction would be more efficient
even though the bus is only 16 bits wide, especially using an address
register indirect with increment addressing mode. If you have the chart
that shows CPU/bus cycles for each instruction, see how many cycles
each of the following code bits takes:
1$ move.l (a0)+,(a1)+
2$ move.w (a0)+,(a1)+
move.w (a0)+,(a1)+
I don't have the chart handy, but I would bet that the first takes
fewer cycles than the second.
--
Roger Chaplin
<[EMAIL PROTECTED]>
--
For information on using the Palm Developer Forums, or to unsubscribe, please see
http://www.palmos.com/dev/tech/support/forums/
