xref: /freebsd/lib/libc/riscv/gen/flt_rounds.c (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
1 /*-
2  * Copyright (c) 2015-2016 Ruslan Bukin <br@bsdpad.com>
3  * All rights reserved.
4  *
5  * Portions of this software were developed by SRI International and the
6  * University of Cambridge Computer Laboratory under DARPA/AFRL contract
7  * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
8  *
9  * Portions of this software were developed by the University of Cambridge
10  * Computer Laboratory as part of the CTSRD Project, with support from the
11  * UK Higher Education Innovation Fund (HEIF).
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #include <sys/types.h>
37 
38 #include <fenv.h>
39 #include <float.h>
40 
41 #ifdef __riscv_float_abi_soft
42 #include "softfloat-for-gcc.h"
43 #include "milieu.h"
44 #include "softfloat.h"
45 #endif
46 
47 int
48 __flt_rounds(void)
49 {
50 	uint64_t mode;
51 
52 #ifdef __riscv_float_abi_soft
53 	mode = __softfloat_float_rounding_mode;
54 #else
55 	__asm __volatile("csrr %0, fcsr" : "=r" (mode));
56 #endif
57 
58 	switch (mode & _ROUND_MASK) {
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 
69 	return (-1);
70 }
71