1*27620987Smatt /* $NetBSD: fpsetround.c,v 1.1 2014/09/03 19:34:25 matt Exp $ */
2*27620987Smatt
3*27620987Smatt /*
4*27620987Smatt * Copyright (c) 1999 The NetBSD Foundation, Inc.
5*27620987Smatt * All rights reserved.
6*27620987Smatt *
7*27620987Smatt * This code is derived from software contributed to The NetBSD Foundation
8*27620987Smatt * by Dan Winship.
9*27620987Smatt *
10*27620987Smatt * Redistribution and use in source and binary forms, with or without
11*27620987Smatt * modification, are permitted provided that the following conditions
12*27620987Smatt * are met:
13*27620987Smatt * 1. Redistributions of source code must retain the above copyright
14*27620987Smatt * notice, this list of conditions and the following disclaimer.
15*27620987Smatt * 2. Redistributions in binary form must reproduce the above copyright
16*27620987Smatt * notice, this list of conditions and the following disclaimer in the
17*27620987Smatt * documentation and/or other materials provided with the distribution.
18*27620987Smatt *
19*27620987Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*27620987Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*27620987Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*27620987Smatt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*27620987Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*27620987Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*27620987Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*27620987Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*27620987Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*27620987Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*27620987Smatt * POSSIBILITY OF SUCH DAMAGE.
30*27620987Smatt */
31*27620987Smatt
32*27620987Smatt #include <sys/cdefs.h>
33*27620987Smatt #if defined(LIBC_SCCS) && !defined(lint)
34*27620987Smatt __RCSID("$NetBSD: fpsetround.c,v 1.1 2014/09/03 19:34:25 matt Exp $");
35*27620987Smatt #endif /* LIBC_SCCS and not lint */
36*27620987Smatt
37*27620987Smatt #include "namespace.h"
38*27620987Smatt
39*27620987Smatt #include <sys/types.h>
40*27620987Smatt #include <ieeefp.h>
41*27620987Smatt #include <powerpc/fpu.h>
42*27620987Smatt
43*27620987Smatt #ifdef __weak_alias
__weak_alias(fpsetround,_fpsetround)44*27620987Smatt __weak_alias(fpsetround,_fpsetround)
45*27620987Smatt #endif
46*27620987Smatt
47*27620987Smatt #define ROUNDBITS FPSCR_RN
48*27620987Smatt
49*27620987Smatt fp_rnd
50*27620987Smatt fpsetround(fp_rnd rnd_dir)
51*27620987Smatt {
52*27620987Smatt union {
53*27620987Smatt double u_d;
54*27620987Smatt uint64_t u_fpscr;
55*27620987Smatt } ud;
56*27620987Smatt fp_rnd old;
57*27620987Smatt
58*27620987Smatt __asm volatile("mffs %0" : "=f"(ud.u_d));
59*27620987Smatt old = (uint32_t)ud.u_fpscr & ROUNDBITS;
60*27620987Smatt ud.u_fpscr &= ~ROUNDBITS;
61*27620987Smatt ud.u_fpscr |= rnd_dir & ROUNDBITS;
62*27620987Smatt __asm volatile("mtfsf 0xff,%0" :: "f"(ud.u_d));
63*27620987Smatt return (old);
64*27620987Smatt }
65