1 /*-
2 * Copyright (c) 2018 Conrad Meyer <cem@freebsd.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 * $FreeBSD$
27 */
28
29 #include "zstd_kfreebsd.h"
30 #include <sys/param.h>
31 #include <sys/endian.h>
32
33 #ifndef _KERNEL
34 #include <strings.h>
35 #endif
36
37 /*
38 * The kernel as a standalone target does not link against libgcc or
39 * libcompiler-rt. On platforms (e.g., MIPS and RISCV) that do not have a
40 * direct assembly implementation of the relevant builtin functions that zstd
41 * references, the compiler converts them into calls to the runtime library
42 * intrinsics. Since the kernel does not link against the runtime libraries,
43 * this results in a failure to link the kernel.
44 *
45 * The goal of the following definitions is to use supported kernel constructs
46 * to implement the same functionality, without adding diff to the Zstd contrib
47 * code.
48 *
49 * A subsequent enhancement might create a mini compiler-rt library for kernel
50 * use and move these over there instead.
51 */
52
53 /* Swap endianness */
54 int
__bswapsi2(int x)55 __bswapsi2(int x)
56 {
57 return (bswap32(x));
58 }
59
60 long long
__bswapdi2(long long x)61 __bswapdi2(long long x)
62 {
63 return (bswap64(x));
64 }
65
66 /* Count trailing zeros */
67 int
__ctzsi2(int x)68 __ctzsi2(int x)
69 {
70 if (x == 0)
71 return (sizeof(x) * NBBY);
72 return (ffs(x) - 1);
73 }
74
75 long long
__ctzdi2(long long x)76 __ctzdi2(long long x)
77 {
78 if (x == 0)
79 return (sizeof(x) * NBBY);
80 return (ffsll(x) - 1);
81 }
82
83 /* Count leading zeros */
84 int
__clzsi2(int x)85 __clzsi2(int x)
86 {
87 return (sizeof(x) * NBBY - fls(x));
88 }
89
90 long long
__clzdi2(long long x)91 __clzdi2(long long x)
92 {
93 return (sizeof(x) * NBBY - flsll(x));
94 }
95