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 Topic: FPU for CCs have any noticeable effect? (Page 1 of 1)
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  Crusoe (Profile)
  4 MB
Posted: Fri Mar 07, 2014 9:51 pm
I did a search first and didn't find a thread on it.

In general use, does this have any effect to OSs snappiness?

More to the point, did Apple write any OS level optimization if present and would non-Apple apps needed to write special code to take advantage of a FPU if present or is automatic to some extent?
  wove (Profile)
Posted: Mon Mar 10, 2014 7:50 am
A computer with an FPU will be faster than a computer without an FPU, if the computer is running software that needs an FPU. So a technical answer is "well it depends."

I think all CC fpus were third party, so from a collector standpoint a CC without an FPU would probably be worth more than one with an FPU. However if you are looking for bragging rights on having a CC that is as fast as possible then having an installed FPU would be necessary.

In 680x0 machine language all floating point opcodes begin with hex F. Opcodes begining with a hex F are treated as a trap and the code is returned to the OS. In the Mac OS a trapped opcode beginning with hex F will be sent to the FPU if one is present. If no FPU is present the opcode is passed to a floating point emulator which is built into the OS.

So for applications an FPU is transparent. The programmer needs to do nothing special to use the FPU. Even an application that would make heavy use of an FPU will run fine on a system without an FPU, but of course it will run slower.

Personally I can think of no current reason a person would use a CC for speed. I think a CC's main use today is more to capture the feeling of a twenty year old "coolness."

  Crusoe (Profile)
  4 MB
Posted: Mon Mar 10, 2014 11:32 pm
Well I ended up grabbing a mystic board and will use that while dabbling around on my CC but of course retaining the original board and will grab up an FPU for completeness.
Thanks and thanks for the info on the opcode too. Cool old eloquent programming.
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