1 files changed, 21 insertions, 41 deletions
diff --git a/src/math/round.c b/src/math/round.c
index bf0b453f..4b38d1fd 100644
--- a/src/math/round.c
+++ b/src/math/round.c
@@ -1,48 +1,28 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/s_round.c */
-/*-
- * Copyright (c) 2003, Steven G. Kargl
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice unmodified, this list of conditions, and the following
- *    disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include <math.h>
+#include "libm.h"
 
 double round(double x)
 {
-	double t;
+	union {double f; uint64_t i;} u = {x};
+	int e = u.i >> 52 & 0x7ff;
+	double_t y;
 
-	if (!isfinite(x))
+	if (e >= 0x3ff+52)
 		return x;
-
-	if (x >= 0.0) {
-		t = floor(x);
-		if (t - x <= -0.5)
-			t += 1.0;
-		return t;
-	} else {
-		t = floor(-x);
-		if (t + x <= -0.5)
-			t += 1.0;
-		return -t;
+	if (u.i >> 63)
+		x = -x;
+	if (e < 0x3ff-1) {
+		/* raise inexact if x!=0 */
+		FORCE_EVAL(x + 0x1p52);
+		return 0*u.f;
 	}
+	y = (double)(x + 0x1p52) - 0x1p52 - x;
+	if (y > 0.5)
+		y = y + x - 1;
+	else if (y <= -0.5)
+		y = y + x + 1;
+	else
+		y = y + x;
+	if (u.i >> 63)
+		y = -y;
+	return y;
 }