minix/lib/libc/arch/arm/hardfloat/fpsetround.c

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/* $NetBSD: fpsetround.c,v 1.8 2013/02/03 01:50:54 matt Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __VFP_FP__
#error FPA is not supported anymore
#endif
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: fpsetround.c,v 1.8 2013/02/03 01:50:54 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <ieeefp.h>
#include <arm/vfpreg.h>
#ifdef __weak_alias
__weak_alias(fpsetround,_fpsetround)
#endif
/*
* Return the current FP rounding mode
*/
fp_rnd
fpsetround(fp_rnd new_rnd)
{
__CTASSERT(__SHIFTOUT(VFP_FPSCR_RN, VFP_FPSCR_RMODE) == FP_RN);
__CTASSERT(__SHIFTOUT(VFP_FPSCR_RP, VFP_FPSCR_RMODE) == FP_RP);
__CTASSERT(__SHIFTOUT(VFP_FPSCR_RM, VFP_FPSCR_RMODE) == FP_RM);
__CTASSERT(__SHIFTOUT(VFP_FPSCR_RZ, VFP_FPSCR_RMODE) == FP_RZ);
uint32_t fpscr;
__asm __volatile("vmrs %0, fpscr" : "=r" (fpscr));
fp_rnd old_rnd = __SHIFTOUT(fpscr, VFP_FPSCR_RMODE);
fpscr ^= __SHIFTIN(new_rnd ^ old_rnd, VFP_FPSCR_RMODE);
__asm __volatile("vmsr fpscr, %0" :: "r" (fpscr));
return old_rnd;
}