From d55cbb5c107d71db667a31461f3b5d7cbdfc589e Mon Sep 17 00:00:00 2001 From: das Date: Sat, 22 Jan 2005 09:53:18 +0000 Subject: Add fma() and fmaf(), which implement a fused multiply-add operation. --- lib/msun/src/s_fmaf.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 lib/msun/src/s_fmaf.c (limited to 'lib/msun/src/s_fmaf.c') diff --git a/lib/msun/src/s_fmaf.c b/lib/msun/src/s_fmaf.c new file mode 100644 index 0000000..1b483b7 --- /dev/null +++ b/lib/msun/src/s_fmaf.c @@ -0,0 +1,47 @@ +/*- + * Copyright (c) 2005 David Schultz + * 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 +__FBSDID("$FreeBSD$"); + +/* + * 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); +} -- cgit v1.1