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Message-Id: <1501171791-23690-7-git-send-email-aleksandar.markovic@rt-rk.com>
Date: Thu, 27 Jul 2017 18:08:49 +0200
From: Aleksandar Markovic <aleksandar.markovic@...rk.com>
To: linux-mips@...ux-mips.org
Cc: Aleksandar Markovic <aleksandar.markovic@...tec.com>,
Miodrag Dinic <miodrag.dinic@...tec.com>,
Goran Ferenc <goran.ferenc@...tec.com>,
"# 4 . 3+" <stable@...r.kernel.org>, Bo Hu <bohu@...gle.com>,
Douglas Leung <douglas.leung@...tec.com>,
James Hogan <james.hogan@...tec.com>,
Jin Qian <jinqian@...gle.com>, linux-kernel@...r.kernel.org,
Paul Burton <paul.burton@...tec.com>,
Petar Jovanovic <petar.jovanovic@...tec.com>,
Raghu Gandham <raghu.gandham@...tec.com>,
Ralf Baechle <ralf@...ux-mips.org>
Subject: [PATCH v4 06/16] MIPS: math-emu: <MAX|MAXA|MIN|MINA>.<D|S>: Fix cases of both inputs zero
From: Aleksandar Markovic <aleksandar.markovic@...tec.com>
Fix the value returned by <MAX|MAXA|MIN|MINA>.<D|S>, if both inputs
are zeros. The right behavior in such cases is stated in instruction
reference manual and is as follows:
fs ft MAX MIN MAXA MINA
---------------------------------------------
0 0 0 0 0 0
0 -0 0 -0 0 -0
-0 0 0 -0 0 -0
-0 -0 -0 -0 -0 -0
Prior to this patch, some of the above cases were yielding correct
results. However, for the sake of code consistency, all such cases
are rewritten in this patch.
A relevant example:
MAX.S fd,fs,ft:
If fs contains +0.0, and ft contains -0.0, fd is going to contain
+0.0 (without this patch, it used to contain -0.0).
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@...tec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@...tec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@...tec.com>
Cc: <stable@...r.kernel.org> # 4.3+
Reviewed-by: James Hogan <james.hogan@...tec.com>
---
arch/mips/math-emu/dp_fmax.c | 8 ++------
arch/mips/math-emu/dp_fmin.c | 8 ++------
arch/mips/math-emu/sp_fmax.c | 8 ++------
arch/mips/math-emu/sp_fmin.c | 8 ++------
4 files changed, 8 insertions(+), 24 deletions(-)
diff --git a/arch/mips/math-emu/dp_fmax.c b/arch/mips/math-emu/dp_fmax.c
index 41bd6ed..31f091a 100644
--- a/arch/mips/math-emu/dp_fmax.c
+++ b/arch/mips/math-emu/dp_fmax.c
@@ -92,9 +92,7 @@ union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y)
return ys ? x : y;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754dp_zero(1);
+ return ieee754dp_zero(xs & ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
DPDNORMX;
@@ -204,9 +202,7 @@ union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y)
return y;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754dp_zero(1);
+ return ieee754dp_zero(xs & ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
DPDNORMX;
diff --git a/arch/mips/math-emu/dp_fmin.c b/arch/mips/math-emu/dp_fmin.c
index 53fb8c9..e607d55 100644
--- a/arch/mips/math-emu/dp_fmin.c
+++ b/arch/mips/math-emu/dp_fmin.c
@@ -92,9 +92,7 @@ union ieee754dp ieee754dp_fmin(union ieee754dp x, union ieee754dp y)
return ys ? y : x;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754dp_zero(1);
+ return ieee754dp_zero(xs | ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
DPDNORMX;
@@ -204,9 +202,7 @@ union ieee754dp ieee754dp_fmina(union ieee754dp x, union ieee754dp y)
return y;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754dp_zero(1);
+ return ieee754dp_zero(xs | ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
DPDNORMX;
diff --git a/arch/mips/math-emu/sp_fmax.c b/arch/mips/math-emu/sp_fmax.c
index d0d73c32..3ca5b20 100644
--- a/arch/mips/math-emu/sp_fmax.c
+++ b/arch/mips/math-emu/sp_fmax.c
@@ -92,9 +92,7 @@ union ieee754sp ieee754sp_fmax(union ieee754sp x, union ieee754sp y)
return ys ? x : y;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754sp_zero(1);
+ return ieee754sp_zero(xs & ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
SPDNORMX;
@@ -204,9 +202,7 @@ union ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y)
return y;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754sp_zero(1);
+ return ieee754sp_zero(xs & ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
SPDNORMX;
diff --git a/arch/mips/math-emu/sp_fmin.c b/arch/mips/math-emu/sp_fmin.c
index 011692e..c982647 100644
--- a/arch/mips/math-emu/sp_fmin.c
+++ b/arch/mips/math-emu/sp_fmin.c
@@ -92,9 +92,7 @@ union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y)
return ys ? y : x;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754sp_zero(1);
+ return ieee754sp_zero(xs | ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
SPDNORMX;
@@ -204,9 +202,7 @@ union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y)
return y;
case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
- if (xs == ys)
- return x;
- return ieee754sp_zero(1);
+ return ieee754sp_zero(xs | ys);
case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
SPDNORMX;
--
2.7.4
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