vx32

Local 9vx git repository for patches.
git clone git://r-36.net/vx32
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s_fmaf.c (1955B)


      1 /*-
      2  * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     24  * SUCH DAMAGE.
     25  */
     26 
     27 /*
     28  * Fused multiply-add: Compute x * y + z with a single rounding error.
     29  *
     30  * A double has more than twice as much precision than a float, so
     31  * direct double-precision arithmetic suffices.
     32  *
     33  * XXX We are relying on the compiler to convert from double to float
     34  *     using the current rounding mode and with the appropriate
     35  *     side-effects.  But on at least one platform (gcc 3.4.2/sparc64),
     36  *     this appears to be too much to ask for.  The precision
     37  *     reduction should be done manually.
     38  */
     39 float
     40 fmaf(float x, float y, float z)
     41 {
     42 
     43 	return ((double)x * y + z);
     44 }