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Re: Unifying the x86 FPU register sets
>>>>> "Jim" == Jim Blandy <jimb@cygnus.com> writes:
>>
>> I suggest $fcseg and $fcoff, $fdseg and $fdoff, instead. People
>> who work a lot with seg:off pairs will recofnise `seg', but not
>> `s'.
Jim> I prefer those names, too. I'm waiting to see what J.T. thinks
Jim> of them.
If GDB can easily handle 48 bit registers, I'd prefer just having $fip
and $fop. info float and/or info all-registers could print them in
seg:offset form if desired.
But if they are to be two registers, I've no objection to using 'seg'
over 's'. I have no objection to using $fdseg and $fdoff over $foseg
and $fooff either, since Intel describes that register as FPU Operand
(Data) Pointer. I do have problems with $fcseg and $fcoff, since
there is nothing that describes the FPU Instruction Pointer as the FPU
Code Pointer.
Jim> We could make the control registers (except $fdoff and $fcoff)
Jim> sixteen-bit values. But that makes more work for platforms that
Jim> do use FSAVE's 32-bit format; I assume those are the majority.
Is there any reason that we can't have 'holes' in the byte array that
holds the register values? We could have 16 bit registers separated
by 16 bit holes.
--jtc
--
J.T. Conklin
RedBack Networks