This might be seen as a dumb question but, do all 386+'s have an onboard FPU built in as standard?
I ask because in cpuid an option is available to set whether an FPU exists or not and i don't want to assume it does when it doesnt and end up with instruction exceptions.
Cheers.
Thanks in advance.
Dangamoose.
FPU's on an i386+
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Jamethiel
RE:FPU's on an i386+
CPUID having a bit to see if an FPU exists is a cruel joke.
The 386 always had to have an external coprocessor.
The 486sx didn't have an on-chip coprocessor, the 486dx did.
All Pentium and better chips have built-in coprocessors (by now a misnomer).
CPUID was introduced on the Pentium and late-model 486dx chips.
As far as I know, if your CPU supports CPUID then it has a math coprocessor (I am willing to be convinced otherwise, but this is what I believe at present).
Hope this helps.
--Jamethiel
The 386 always had to have an external coprocessor.
The 486sx didn't have an on-chip coprocessor, the 486dx did.
All Pentium and better chips have built-in coprocessors (by now a misnomer).
CPUID was introduced on the Pentium and late-model 486dx chips.
As far as I know, if your CPU supports CPUID then it has a math coprocessor (I am willing to be convinced otherwise, but this is what I believe at present).
Hope this helps.
--Jamethiel