--- zzzz-none-000/linux-3.10.107/arch/mips/math-emu/ieee754dp.c	2017-06-27 09:49:32.000000000 +0000
+++ vr9-7490-729/linux-3.10.107/arch/mips/math-emu/ieee754dp.c	2021-11-10 11:53:54.000000000 +0000
@@ -41,7 +41,9 @@
 int ieee754dp_issnan(ieee754dp x)
 {
 	assert(ieee754dp_isnan(x));
-	return ((DPMANT(x) & DP_MBIT(DP_MBITS-1)) == DP_MBIT(DP_MBITS-1));
+	if (ieee754_csr.nan2008)
+		return !(DPMANT(x) & DP_MBIT(DP_MBITS-1));
+	return (DPMANT(x) & DP_MBIT(DP_MBITS-1));
 }