Unifying the x86 FPU register sets

Eli Zaretskii eliz@gnu.org
Thu Oct 21 04:43:00 GMT 1999


> I don't think having an 48-bit $fip and $fop is a good idea.  At least
> in 32-bit protected mode they really are segment selector and offset
> pairs.  The segment selector is used to lookup the linear address of
> the segment via the LDT.  This is conceptually very different from the
> offset.  This is probably also the reason why Jim had initially chosen
> $fcs and $fds for the segment selector of the instruction pointer and
> operand (data) pointer.

If we want to be pedantic, it's not a segment selector, but a segment
descriptor selector.

I think it's not important to make the distinction.  Many people say
"DS segment" in protected mode also.


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