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Re: patch to fix rtl documentation for new floating point comparisons
- From: Andreas Schwab <schwab at suse dot de>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Kenneth Zadeck <zadeck at naturalbridge dot com>, Richard Earnshaw <Richard dot Earnshaw at foss dot arm dot com>, Paolo Bonzini <bonzini at gnu dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 18 Feb 2015 09:38:28 +0100
- Subject: Re: patch to fix rtl documentation for new floating point comparisons
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Joseph Myers <joseph@codesourcery.com> writes:
> For example, on MIPS the C.cond.fmt instruction has a four-bit condition
> field: "In the cond field of the instruction: cond 2..1 specify the nature
> of the comparison (equals, less than, and so on); cond 0 specifies whether
> the comparison is ordered or unordered, i.e. false or true if any operand
> is a NaN; cond 3 indicates whether the instruction should signal an
> exception on QNaN inputs, or not". Together with possibly negating the
> result you get all 32 possible comparisons (choice of whether the
> comparison is true or false for each of = < > unordered, choice of whether
> to raise invalid for quiet NaNs).
The m68k fpu has the same feature.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
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