Mail Archives: djgpp/1993/12/17/19:09:24
Dieter ("buers AT dg1 DOT chemie DOT uni-konstanz DOT de") writes:
> I probably was wrong. I overlooked, that the `finit' instruction will reset
> the control word (correct?). The code section for initialization is
yes, finit does a complete initialization of the FPU.
> I was suspicious because I found better results with a math test package
> (paranoia), after setting the control word to 0x137f.
The only difference you should see would be due to the FPU no longer
causing interrupts.
btw, paranoia is quite a good program but it is by no means perfect.
In particular, it does not handle very well the case where the
precision of intermediate results is different from the prevailing
precision _and_ the intermediate results have less than twice the
precision of the prevailing precision:
variables declared FPU precision paranoia
as: control: report:
float 24 bits ok
float 53 bits ok
float 64 bits ok
double 53 bits ok
double 64 bits reports FLAWs
The FLAW reported by paranoia in the last case is not a FLAW in the
FPU, and in my opinion (but I suspect that there are others who would
argue with this) should not be regarded as a FLAW at all.
--Bill
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