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Re: IA32: printing FP register variables
- To: egcs@egcs.cygnus.com, gdb@sourceware.cygnus.com
- Subject: Re: IA32: printing FP register variables
- From: Jim Blandy <jimb@cygnus.com>
- Date: 13 Jul 1999 16:21:57 -0500
- References: <9500.931826533@upchuck.cygnus.com>
I hope that I'm not mixing up my priorities by worrying about debug
size. But since a register numbering is a matter of public protocol,
it will be more trouble to change it later than to make a good choice
now.
There are only three possible numberings that make any sense:
physical, top-relative, or base-relative.
Physical is not possible, since the compiler doesn't know the value of
TOP at function entry.
top-relative is, I think we all agree, the least stable of all
possible orderings.
So base-relative is what we have left. We will still require LRS info
in almost every case, but it's better than the alternatives.
If GCC will have trouble generating base-relative register numbers
(if, for example, regstack has no concept of the FP stack base), then
that would tip the scales. If someone can find an i386 STABS system
that uses another numbering, that would too.