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Subject: Re: Thoughts about board representations...

Author: Tom Kerrigan

Date: 21:50:06 02/10/00

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On February 10, 2000 at 23:21:09, Robert Hyatt wrote:

>On February 10, 2000 at 22:03:24, Tom Kerrigan wrote:
>
>>On February 10, 2000 at 17:50:54, Robert Hyatt wrote:
>>
>>>There are pros and cons for all implementations.  The pros for bitmaps don't
>>>become apparent until they are run on a 'native' architecture (64 bit machines).
>>>When all is said and done, it is likely that both approaches are going to end
>>>up pretty much equal, except for the 'data width' problem.  IE an 0x88 program
>>
>>But you can look at the "data width" problem from the other direction: bitmaps
>>don't run efficiently on non-64-bit processors.
>>
>>I like having a program that runs reasonably well on a small processor with
>>small memory...
>>
>>-Tom
>
>
>Two important points:  (1) 64 bits are the future, not 32 bits,  So in 5 years,
>32 bits will probably be like 286's today.
>
>(2) super-scalar architectures have a problem keeping both pipes full.  Bitmap
>programs aren't as inefficient as first suspected, as they offer thousands of
>places where two 32 bit and/or/xor/etc operations are needed to complete a 64
>bit operation.  Super-scalar eats that alive and makes the penalty much less
>than expected.  IE I'll bet a bitmap program actually executes 2 instructions
>per clock way more than a non-bitmap program, which means part of the 'loss'
>is covered by clever hardware...

I was thinking more about the 68000 in the PalmPilot and the various RISC
processors in Windows CE computers...
-Tom



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