flt_rounds.c revision 266337 
1/*-
2 * Copyright (c) 2012 Ian Lepore <freebsd@damnhippie.dyndns.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/10/lib/libc/arm/gen/flt_rounds.c 266337 2014-05-17 18:53:36Z ian $");
29
30#include <fenv.h>
31#include <float.h>
32
33#ifndef __ARM_PCS_VFP
34#include "softfloat-for-gcc.h"
35#include "milieu.h"
36#include "softfloat.h"
37#endif
38
39int
40__flt_rounds(void)
41{
42	int mode;
43
44#ifndef __ARM_PCS_VFP
45	/*
46	 * Translate our rounding modes to the unnamed
47	 * manifest constants required by C99 et. al.
48	 */
49	mode = __softfloat_float_rounding_mode;
50#else /* __ARM_PCS_VFP */
51	/*
52	 * Read the floating-point status and control register
53	 */
54	__asm __volatile("vmrs %0, fpscr" : "=&r"(mode));
55	mode &= _ROUND_MASK;
56#endif /* __ARM_PCS_VFP */
57
58	switch (mode) {
59	case FE_TOWARDZERO:
60		return (0);
61	case FE_TONEAREST:
62		return (1);
63	case FE_UPWARD:
64		return (2);
65	case FE_DOWNWARD:
66		return (3);
67	}
68	return (-1);
69}
70