releases/4.9.52/mips-math-emu-maxa-mina-.-d-s-fix-cases-of-input-values-with-opposite-signs.patch

   1 From 1a41b3b441508ae63b1a9ec699ec94065739eb60 Mon Sep 17 00:00:00 2001
   2 From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
   3 Date: Thu, 27 Jul 2017 18:08:51 +0200
   4 Subject: MIPS: math-emu: <MAXA|MINA>.<D|S>: Fix cases of input values with opposite signs
   5
   6 From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
   7
   8 commit 1a41b3b441508ae63b1a9ec699ec94065739eb60 upstream.
   9
  10 Fix the value returned by <MAXA|MINA>.<D|S>, if the inputs are normal
  11 fp numbers of the same absolute value, but opposite signs.
  12
  13 A relevant example:
  14
  15 MAXA.S fd,fs,ft:
  16   If fs contains -3.0, and ft contains +3.0, fd is going to contain
  17   +3.0 (without this patch, it used to contain -3.0).
  18
  19 Fixes: a79f5f9ba508 ("MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction")
  20 Fixes: 4e9561b20e2f ("MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction")
  21
  22 Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
  23 Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
  24 Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
  25 Reviewed-by: James Hogan <james.hogan@imgtec.com>
  26 Cc: Bo Hu <bohu@google.com>
  27 Cc: Douglas Leung <douglas.leung@imgtec.com>
  28 Cc: Jin Qian <jinqian@google.com>
  29 Cc: Paul Burton <paul.burton@imgtec.com>
  30 Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
  31 Cc: Raghu Gandham <raghu.gandham@imgtec.com>
  32 Cc: linux-mips@linux-mips.org
  33 Cc: linux-kernel@vger.kernel.org
  34 Patchwork: https://patchwork.linux-mips.org/patch/16883/
  35 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  36 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  37
  38 ---
  39  arch/mips/math-emu/dp_fmax.c |    8 ++++++--
  40  arch/mips/math-emu/dp_fmin.c |    6 +++++-
  41  arch/mips/math-emu/sp_fmax.c |    8 ++++++--
  42  arch/mips/math-emu/sp_fmin.c |    6 +++++-
  43  4 files changed, 22 insertions(+), 6 deletions(-)
  44
  45 --- a/arch/mips/math-emu/dp_fmax.c
  46 +++ b/arch/mips/math-emu/dp_fmax.c
  47 @@ -243,7 +243,11 @@ union ieee754dp ieee754dp_fmaxa(union ie
  48                 return y;
  49
  50         /* Compare mantissa */
  51 -       if (xm <= ym)
  52 +       if (xm < ym)
  53                 return y;
  54 -       return x;
  55 +       else if (xm > ym)
  56 +               return x;
  57 +       else if (xs == 0)
  58 +               return x;
  59 +       return y;
  60  }
  61 --- a/arch/mips/math-emu/dp_fmin.c
  62 +++ b/arch/mips/math-emu/dp_fmin.c
  63 @@ -243,7 +243,11 @@ union ieee754dp ieee754dp_fmina(union ie
  64                 return x;
  65
  66         /* Compare mantissa */
  67 -       if (xm <= ym)
  68 +       if (xm < ym)
  69 +               return x;
  70 +       else if (xm > ym)
  71 +               return y;
  72 +       else if (xs == 1)
  73                 return x;
  74         return y;
  75  }
  76 --- a/arch/mips/math-emu/sp_fmax.c
  77 +++ b/arch/mips/math-emu/sp_fmax.c
  78 @@ -243,7 +243,11 @@ union ieee754sp ieee754sp_fmaxa(union ie
  79                 return y;
  80
  81         /* Compare mantissa */
  82 -       if (xm <= ym)
  83 +       if (xm < ym)
  84                 return y;
  85 -       return x;
  86 +       else if (xm > ym)
  87 +               return x;
  88 +       else if (xs == 0)
  89 +               return x;
  90 +       return y;
  91  }
  92 --- a/arch/mips/math-emu/sp_fmin.c
  93 +++ b/arch/mips/math-emu/sp_fmin.c
  94 @@ -243,7 +243,11 @@ union ieee754sp ieee754sp_fmina(union ie
  95                 return x;
  96
  97         /* Compare mantissa */
  98 -       if (xm <= ym)
  99 +       if (xm < ym)
 100 +               return x;
 101 +       else if (xm > ym)
 102 +               return y;
 103 +       else if (xs == 1)
 104                 return x;
 105         return y;
 106  }