X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmath%2Fscalbn.c;h=182f561068fda7bc8321dfc7991df8b6d58e1b56;hb=6ae2568bc2367b4d47e0ea1cb043fd56e697912f;hp=530e07c79f051aab246f39b31bfa1571699a8f57;hpb=2eaed464e2080d8321d3903b71086a1ecfc4ee4a;p=musl

diff --git a/src/math/scalbn.c b/src/math/scalbn.c
index 530e07c7..182f5610 100644
--- a/src/math/scalbn.c
+++ b/src/math/scalbn.c
@@ -16,11 +16,13 @@ double scalbn(double x, int n)
 				n = 1023;
 		}
 	} else if (n < -1022) {
-		y *= 0x1p-1022;
-		n += 1022;
+		/* make sure final n < -53 to avoid double
+		   rounding in the subnormal range */
+		y *= 0x1p-1022 * 0x1p53;
+		n += 1022 - 53;
 		if (n < -1022) {
-			y *= 0x1p-1022;
-			n += 1022;
+			y *= 0x1p-1022 * 0x1p53;
+			n += 1022 - 53;
 			if (n < -1022)
 				n = -1022;
 		}