/*      $NetBSD: fpsetsticky.c,v 1.1 2014/09/03 19:34:25 matt Exp $     */

/*
* Copyright (c) 1999 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Dan Winship.
*
* 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.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: fpsetsticky.c,v 1.1 2014/09/03 19:34:25 matt Exp $");
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"

#include <sys/types.h>
#include <ieeefp.h>
#include <powerpc/fpu.h>

#define STICKYBITS      (FPSCR_XX|FPSCR_ZX|FPSCR_UX|FPSCR_OX|FPSCR_VX)
#define INVBITS         (FPSCR_VXCVI|FPSCR_VXSQRT|FPSCR_VXSOFT|FPSCR_VXVC|\
                        FPSCR_VXIMZ|FPSCR_VXZDZ|FPSCR_VXIDI|FPSCR_VXISI|\
                        FPSCR_VXSNAN)
#define STICKYSHFT      25

#ifdef __weak_alias
__weak_alias(fpsetsticky,_fpsetsticky)
#endif

fp_except
fpsetsticky(fp_except mask)
{
       union {
               double u_d;
               uint64_t u_fpscr;
       } ud;
       fp_except old;

       __asm volatile("mffs %0" : "=f"(ud.u_d));
       old = ((uint32_t)ud.u_fpscr & STICKYBITS) >> STICKYSHFT;
       /*
        * FPSCR_VX (aka FP_X_INV) is not a sticky bit but a summary of the
        * all the FPSCR_VX* sticky bits.  So when FP_X_INV is cleared then
        * clear all of those bits, likewise when it's set, set them all.
        */
       if ((mask & FP_X_INV) == 0)
               ud.u_fpscr &= ~INVBITS;
       else
               ud.u_fpscr |= INVBITS;
       ud.u_fpscr &= ~STICKYBITS;
       ud.u_fpscr |= ((uint32_t)mask << STICKYSHFT) & STICKYBITS;
       /*
        * Make FPSCR_FX reflect the presence of a set sticky bit (or not).
        */
       if (ud.u_fpscr & (STICKYBITS|INVBITS))
               ud.u_fpscr |= FPSCR_FX;
       else
               ud.u_fpscr &= ~FPSCR_FX;
       /*
        * Write back the fpscr.
        */
       __asm volatile("mtfsf 0xff,%0" :: "f"(ud.u_d));
       return (old);
}