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Re: Proposal for `info float' layout


   Date: Mon, 1 Nov 1999 09:09:50 -0800 (PST)
   From: hjl@lucon.org (H.J. Lu)

   May I suggest we use

   R3: Special 0x00000000000000000000 Denormal 0.0024438394034300000
   R4: Empty   0x00000000000000000000 Zero	    0
   R4: Empty   0x00000000000000000000 Normal   1.0

   It is more consistent and easy to read.

Thanks for your suggestion.  It gives me the opportunity to say a few
things about how I came to my proposal for the new layout.

While your suggested layout may seem more consistent, I don't think it
is easier to read.

Keep in mind that GDB is a debugger.  We should try to create the
layout that is most useful for finding bugs.  Based on this principle
I made some decisions:

 * My code deliberately does not try to interpret the contents of
   empty registers.  Doing so would needlesly clutter the display with
   information that is almost certainly irrelevent, thus making it
   harder to find information that is relevant.  If you really want
   the contents of an empty register as a floating point number, you
   can always display the register by using GDB's `print' command.

 * My code deliberately prints only a further classification of a
   floating point number if it is `Denormal' or `Pseudo-denormal'.
   This makes denormals stand out which is important since a denormal
   is a clear sign for problematic code.  The user's program might
   perform poorly since it is losing precision.

   I think zeroes stand out enough for themselves, and a normal number
   is ... well, a normal number.  Nothing special and doesn't require
   any additional attention.  Only its value is relevant.

Mark

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