MIPS: math-emu: <MAXA|MINA>.<D|S>: Fix cases of both infinite inputs
authorAleksandar Markovic <aleksandar.markovic@imgtec.com>
Thu, 27 Jul 2017 16:08:52 +0000 (18:08 +0200)
committerRalf Baechle <ralf@linux-mips.org>
Tue, 29 Aug 2017 13:21:55 +0000 (15:21 +0200)
commit3444c4eb534c20e44f0d6670b34263efaf8b531f
treeaf52c4f4afae51b1568475d8b0c81303567ba241
parent1a41b3b441508ae63b1a9ec699ec94065739eb60
MIPS: math-emu: <MAXA|MINA>.<D|S>: Fix cases of both infinite inputs

Fix the value returned by <MAXA|MINA>.<D|S> fd,fs,ft, if both inputs
are infinite. The previous implementation returned always the value
contained in ft in such cases. The correct behavior is specified
in Mips instruction set manual and is as follows:

    fs    ft        MAXA     MINA
  ---------------------------------
    inf   inf        inf      inf
    inf  -inf        inf     -inf
   -inf   inf        inf     -inf
   -inf  -inf       -inf     -inf

A relevant example:

MAXA.S fd,fs,ft:
  If fs contains +inf, and ft contains -inf, fd is going to contain
  +inf (without this patch, it used to contain -inf).

Fixes: a79f5f9ba508 ("MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction")
Fixes: 4e9561b20e2f ("MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction")

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Bo Hu <bohu@google.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: Jin Qian <jinqian@google.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.3+
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16884/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
arch/mips/math-emu/dp_fmax.c
arch/mips/math-emu/dp_fmin.c
arch/mips/math-emu/sp_fmax.c
arch/mips/math-emu/sp_fmin.c