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authorThe Android Open Source Project <initial-contribution@android.com>2008-10-21 07:00:00 -0700
committerThe Android Open Source Project <initial-contribution@android.com>2008-10-21 07:00:00 -0700
commita27d2baa0c1a2ec70f47ea9199b1dd6762c8a349 (patch)
treedefd1cc07d16ad2f3b21154114e092d11c94c5bb /libm/src/s_fmaf.c
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Initial Contributionandroid-1.0
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diff --git a/libm/src/s_fmaf.c b/libm/src/s_fmaf.c
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+/*-
+ * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
+ * 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, 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 <sys/cdefs.h>
+/* __FBSDID("$FreeBSD: src/lib/msun/src/s_fmaf.c,v 1.1 2005/01/22 09:53:18 das Exp $"); */
+
+/*
+ * Fused multiply-add: Compute x * y + z with a single rounding error.
+ *
+ * A double has more than twice as much precision than a float, so
+ * direct double-precision arithmetic suffices.
+ *
+ * XXX We are relying on the compiler to convert from double to float
+ * using the current rounding mode and with the appropriate
+ * side-effects. But on at least one platform (gcc 3.4.2/sparc64),
+ * this appears to be too much to ask for. The precision
+ * reduction should be done manually.
+ */
+float
+fmaf(float x, float y, float z)
+{
+
+ return ((double)x * y + z);
+}