More SSE infrastructure

Mark Kettenis kettenis@wins.uva.nl
Wed Jul 5 12:08:00 GMT 2000


   Date: Wed, 5 Jul 2000 10:56:00 -0700
   From: Richard Henderson <rth@cygnus.com>

   Next question: will GDB accept negative octal constants for
   signed 128-bit types?  E.g. -017777.  I surely don't want to
   do decimal output without libgmp on my side, which we don't
   want to assume.

Not with the explicit minus sign.  You specify the sign bit as part of
the octal number, e.g. 020000 for your example (the range would be
specified as 020000;017777; in this case).  This is exactly what is
already done for `long' and `long long'.

   It wouldn't be the end of the world if we wound up considering
   all such types unsigned in the debugger, but if it's possible...

Looks like GDB treats those extremely large integers as unsigned
anyway :-(.  I might take a look on a rainy day or so ...

   > If printing correct lower and upper bounds is too hard for GCC, there
   > are alternatives.  If the lower bound is 0 and the upper bound is a
   > negative number, GDB assumes the size of the type (in bytes) is the
   > absolute value of the upper bound.  I've verified that emitting:
   > 
   > .stabs "__m128:t(0,20)=r(0,20);0;-16;",128,0,0,0
   > 
   > does indeed work.  The GNU stabs info file suggests that this is a
   > Convex convention.

   Interesting to know.  However, I would imagine that not all
   stabs system debuggers allow such a thing, so it'd be better
   to go with printing proper bounds if possible.

I'd be really surprised if those stabs system debugger would allow
large integers at all.

Mark


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