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      1 /*	$NetBSD: flt_rounds.c,v 1.12 2015/03/19 21:22:59 joerg Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1996 Mark Brinicombe
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *      This product includes software developed by Mark Brinicombe
     18  *	for the NetBSD Project.
     19  * 4. The name of the author may not be used to endorse or promote products
     20  *    derived from this software without specific prior written permission
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 #if defined(LIBC_SCCS) && !defined(lint)
     36 __RCSID("$NetBSD: flt_rounds.c,v 1.12 2015/03/19 21:22:59 joerg Exp $");
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 #include "namespace.h"
     40 #include <ieeefp.h>
     41 #include <float.h>
     42 #include <stdint.h>
     43 #include <powerpc/fpu.h>
     44 
     45 static const int map[] = {
     46 	1,	/* round to nearest */
     47 	0,	/* round to zero */
     48 	2,	/* round to positive infinity */
     49 	3	/* round to negative infinity */
     50 };
     51 
     52 int
     53 __flt_rounds(void)
     54 {
     55 #ifdef _SOFT_FLOAT
     56 	return map[fpgetround()];
     57 #else
     58 	union {
     59 		double u_d;
     60 		uint64_t u_fpscr;
     61 	} ud;
     62 
     63 	__asm volatile("mffs %0" : "=f"(ud.u_d));
     64 	return map[((uint32_t)ud.u_fpscr & FPSCR_RN)];
     65 #endif
     66 }
     67