[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 b801cd6..9b367a6 100644
--- a/arch/arm/vfp/vfpdouble.c
+++ b/arch/arm/vfp/vfpdouble.c
@@ -770,6 +770,9 @@
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;
