From: Catalin Marinas <catalin.marinas@arm.com>
Date: Wed, 3 Aug 2005 18:53:25 +0000 (+0100)
Subject: [PATCH] ARM: 2841/1: Fix VFP +/-0 case for doubles addition
X-Git-Tag: v2.6.13-rc6~74^2~2
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=7b1fbf292bb4c855ddae8add8c459e94684f7543;p=~emulex%2Finfiniband.git

[PATCH] ARM: 2841/1: Fix VFP +/-0 case for doubles addition

Patch from Catalin Marinas

The IEEE 754 standard specifies that the result of (x - x), where x is
a valid number, should be -0 if the rounding mode is towards minus
infinity or +0 otherwise.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/vfp/vfpdouble.c b/arch/arm/vfp/vfpdouble.c
index b801cd66b6e..9b367a65cb4 100644
--- a/arch/arm/vfp/vfpdouble.c
+++ b/arch/arm/vfp/vfpdouble.c
@@ -770,6 +770,9 @@ vfp_double_add(struct vfp_double *vdd, struct vfp_double *vdn,
 		if ((s64)m_sig < 0) {
 			vdd->sign = vfp_sign_negate(vdd->sign);
 			m_sig = -m_sig;
+		} else if (m_sig == 0) {
+			vdd->sign = (fpscr & FPSCR_RMODE_MASK) ==
+				      FPSCR_ROUND_MINUSINF ? 0x8000 : 0;
 		}
 	} else {
 		m_sig += vdn->significand;