flt_rounds.c revision 1.2
1/* $NetBSD: flt_rounds.c,v 1.2 2022/04/08 10:17:52 andvar Exp $ */ 2 3/*- 4 * Copyright (c) 2014 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas of 3am Software Foundry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <sys/cdefs.h> 33#if defined(LIBC_SCCS) && !defined(lint) 34__RCSID("$NetBSD: flt_rounds.c,v 1.2 2022/04/08 10:17:52 andvar Exp $"); 35#endif /* LIBC_SCCS and not lint */ 36 37#include <sys/param.h> 38#include <sys/types.h> 39#include <ieeefp.h> 40 41#include <aarch64/armreg.h> 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 positive infinity 51 * 3 - round to negative infinity 52 * 53 * However, the rounding modes stored in the FPCR are: 54 * 0 - round to nearest 55 * 1 - round to positive infinity 56 * 2 - round to negative infinity 57 * 3 - round to zero 58 * 59 * To convert, just add 1 and then mask with 3. 60 */ 61 62int __flt_rounds(void); 63 64int 65__flt_rounds(void) 66{ 67 return (__SHIFTOUT(reg_fpcr_read(), FPCR_RMODE) + 1) & 3; 68} 69