1 /* $NetBSD: flt_rounds.c,v 1.1 2000/12/29 20:13:48 bjh21 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/types.h> 35 #include <ieeefp.h> 36 37 static const int map[] = { 38 1, /* round to nearest */ 39 2, /* round to positive infinity */ 40 3, /* round to negative infinity */ 41 0 /* round to zero */ 42 }; 43 44 /* 45 * Return the current FP rounding mode 46 * 47 * Returns: 48 * 0 - round to zero 49 * 1 - round to nearest 50 * 2 - round to postive infinity 51 * 3 - round to negative infinity 52 * 53 * ok all we need to do is get the current FP rounding mode 54 * index our map table and return the appropriate value. 55 * 56 * HOWEVER: 57 * The ARM FPA codes the rounding mode into the actual FP instructions 58 * so there is no such thing as a global rounding mode. 59 * The default is round to nearest if rounding is not explictly specified. 60 * FP instructions generated by GCC will not explicitly specify a rounding 61 * mode. 62 * 63 * So the best we can do it to return the rounding mode FP instructions 64 * use if rounding is not specified which is round to nearest. 65 * 66 * This could change in the future with new floating point emulators or 67 * soft float FP libraries. 68 */ 69 70 int __flt_rounds(void); 71 72 int 73 __flt_rounds() 74 { 75 return(map[fpgetround()]); 76 } 77