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flt_rounds.c revision 1.7 
      1 /*	$NetBSD: flt_rounds.c,v 1.7 2004/04/04 19:26:21 matt 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 <ieeefp.h>
     35 #include <float.h>
     36 #include <stdint.h>
     37 #include <powerpc/fpu.h>
     38 
     39 static const int map[] = {
     40 	1,	/* round to nearest */
     41 	0,	/* round to zero */
     42 	2,	/* round to positive infinity */
     43 	3	/* round to negative infinity */
     44 };
     45 
     46 int
     47 __flt_rounds(void)
     48 {
     49 #ifdef _SOFT_FLOAT
     50 	return map[fpgetround()];
     51 #else
     52 	uint64_t fpscr;
     53 
     54 	__asm__ __volatile("mffs %0" : "=f"(fpscr));
     55 	return map[((uint32_t)fpscr & FPSCR_RN)];
     56 #endif
     57 }
     58