Ah, my children, my children let me tell you 'bout the good old days.
<g> Usta was you could run FPU and Integer instructions concurrently
with integer instructions in a singe CPU machine at least in DEC's
PDP-11s. I imagine the quad PDP-11 (PDP-11/70) could have run four of
each concurrently. In those days the FPU was a separate card and it
ran asynchronous from the main CPU. It took about 20+ microseconds to
do a division which was about 20 times longer than an integer
operation. However, (to my knowledge) none of the operating systems
that ran on the PDP-11 family (RT-11, RSX..., RSTS, or UNIX) took
advantage of the time an operation was going on in the FPU to do some
other form of useful work in the CPU. I think that the FPU and CPU
architecture of INTEL is pretty much the same and work could be done
concurrently but isn't.
>How are you going to have _two different threads_ access the same cpu at
>the same time? I read his question to be "can one thread use the FPU
>while the other thread uses the normal integer processing CPU. the
>answer is no. Because the cpu/fpu combination has one program counter,
>one cpu state. Unless I have overlooked some remarkable CPU breakthrough
>from Intel, that is...
>
>
>Robert Hyatt Computer and Information Sciences
>[EMAIL PROTECTED] University of Alabama at Birmingham
>(205) 934-2213 115A Campbell Hall, UAB Station
>(205) 934-5473 FAX Birmingham, AL 35294-1170
END
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