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fpsetround.c revision 1.3.4.1 
      1  1.3.4.1  nathanw /* $NetBSD: fpsetround.c,v 1.3.4.1 2001/10/08 20:16:51 nathanw 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  1.3.4.1  nathanw 	__asm__("excb");
     48      1.1      cgd 	__asm__("mf_fpcr %0" : "=f" (fpcrval));
     49      1.1      cgd 	old = *(u_int64_t *)&fpcrval;
     50      1.1      cgd 
     51      1.1      cgd 	new = old & ~(long)0x0c00000000000000;
     52      1.1      cgd 	new = (long)rnd_dir << 58;
     53      1.1      cgd 	*(u_int64_t *)&fpcrval = new;
     54      1.1      cgd 
     55      1.1      cgd 	__asm__("mt_fpcr %0" : : "f" (fpcrval));
     56  1.3.4.1  nathanw 	__asm__("excb");
     57      1.1      cgd 
     58      1.1      cgd 	return ((old >> 58) & 0x3);
     59      1.1      cgd }
     60