X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmath%2Ffmal.c;h=4506aac6f6abbe9545f0674dd645c121f5198617;hb=06d4075a50b84d4b80e09eb5662fc1153bd559f7;hp=c68db25525a557d96ba0e262dc00095d25fe476c;hpb=34660d73bd0db29469d2758e1b48d2360edf3a2f;p=musl

diff --git a/src/math/fmal.c b/src/math/fmal.c
index c68db255..4506aac6 100644
--- a/src/math/fmal.c
+++ b/src/math/fmal.c
@@ -264,12 +264,24 @@ long double fmal(long double x, long double y, long double z)
 		/*
 		 * There is no need to worry about double rounding in directed
 		 * rounding modes.
-		 * TODO: underflow is not raised correctly, example in downward rounding:
+		 * But underflow may not be raised correctly, example in downward rounding:
 		 * fmal(0x1.0000000001p-16000L, 0x1.0000000001p-400L, -0x1p-16440L)
 		 */
+		long double ret;
+#if defined(FE_INEXACT) && defined(FE_UNDERFLOW)
+		int e = fetestexcept(FE_INEXACT);
+		feclearexcept(FE_INEXACT);
+#endif
 		fesetround(oround);
 		adj = r.lo + xy.lo;
-		return scalbnl(r.hi + adj, spread);
+		ret = scalbnl(r.hi + adj, spread);
+#if defined(FE_INEXACT) && defined(FE_UNDERFLOW)
+		if (ilogbl(ret) < -16382 && fetestexcept(FE_INEXACT))
+			feraiseexcept(FE_UNDERFLOW);
+		else if (e)
+			feraiseexcept(FE_INEXACT);
+#endif
+		return ret;
 	}
 
 	adj = add_adjusted(r.lo, xy.lo);