xref: /freebsd/lib/libc/riscv/gen/flt_rounds.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
1 /*-
2  * Copyright (c) 2015 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 __FBSDID("$FreeBSD$");
37 
38 #include <sys/types.h>
39 
40 #include <fenv.h>
41 #include <float.h>
42 
43 int
44 __flt_rounds(void)
45 {
46 #if 0
47 	uint64_t fcsr;
48 #endif
49 	int mode;
50 
51 #if 0
52 	__asm __volatile("csrr    %0, fcsr" : "=r" (fcsr));
53 	mode = (fcsr & _ROUND_MASK);
54 #endif
55 
56 	/* RISCVTODO */
57 	mode = FE_TOWARDZERO; /* softfloat rounding mode */
58 
59 	switch (mode) {
60 	case FE_TOWARDZERO:
61 		return (0);
62 	case FE_TONEAREST:
63 		return (1);
64 	case FE_UPWARD:
65 		return (2);
66 	case FE_DOWNWARD:
67 		return (3);
68 	}
69 
70 	return (-1);
71 }
72