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fpsetround.c revision 1.4 
      1  1.4  ross /* $NetBSD: fpsetround.c,v 1.4 2001/04/26 03:23:18 ross Exp $ */
      2  1.1   cgd 
      3  1.1   cgd /*
      4  1.1   cgd  * Copyright (c) 1995 Christopher G. Demetriou
      5  1.1   cgd  * All rights reserved.
      6  1.3   cgd  *
      7  1.1   cgd  * Redistribution and use in source and binary forms, with or without
      8  1.1   cgd  * modification, are permitted provided that the following conditions
      9  1.1   cgd  * are met:
     10  1.1   cgd  * 1. Redistributions of source code must retain the above copyright
     11  1.1   cgd  *    notice, this list of conditions and the following disclaimer.
     12  1.1   cgd  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.1   cgd  *    notice, this list of conditions and the following disclaimer in the
     14  1.1   cgd  *    documentation and/or other materials provided with the distribution.
     15  1.1   cgd  * 3. All advertising materials mentioning features or use of this software
     16  1.1   cgd  *    must display the following acknowledgement:
     17  1.3   cgd  *          This product includes software developed for the
     18  1.3   cgd  *          NetBSD Project.  See http://www.netbsd.org/ for
     19  1.3   cgd  *          information about NetBSD.
     20  1.1   cgd  * 4. The name of the author may not be used to endorse or promote products
     21  1.3   cgd  *    derived from this software without specific prior written permission.
     22  1.3   cgd  *
     23  1.1   cgd  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     24  1.1   cgd  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     25  1.1   cgd  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     26  1.1   cgd  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     27  1.1   cgd  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     28  1.1   cgd  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     29  1.1   cgd  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     30  1.1   cgd  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     31  1.1   cgd  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     32  1.1   cgd  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     33  1.3   cgd  *
     34  1.3   cgd  * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
     35  1.1   cgd  */
     36  1.1   cgd 
     37  1.1   cgd #include <sys/types.h>
     38  1.1   cgd #include <ieeefp.h>
     39  1.1   cgd 
     40  1.1   cgd fp_rnd
     41  1.1   cgd fpsetround(rnd_dir)
     42  1.1   cgd 	fp_rnd rnd_dir;
     43  1.1   cgd {
     44  1.1   cgd 	double fpcrval;
     45  1.1   cgd 	u_int64_t old, new;
     46  1.1   cgd 
     47  1.1   cgd 	__asm__("mf_fpcr %0" : "=f" (fpcrval));
     48  1.1   cgd 	old = *(u_int64_t *)&fpcrval;
     49  1.1   cgd 
     50  1.1   cgd 	new = old & ~(long)0x0c00000000000000;
     51  1.1   cgd 	new = (long)rnd_dir << 58;
     52  1.1   cgd 	*(u_int64_t *)&fpcrval = new;
     53  1.1   cgd 
     54  1.4  ross 	__asm__("excb");
     55  1.1   cgd 	__asm__("mt_fpcr %0" : : "f" (fpcrval));
     56  1.4  ross 	__asm__("excb");
     57  1.1   cgd 
     58  1.1   cgd 	return ((old >> 58) & 0x3);
     59  1.1   cgd }
     60