1/*
2 * Platform-specific definitions for Skein hash function.
3 *
4 * Source code author: Doug Whiting, 2008.
5 *
6 * This algorithm and source code is released to the public domain.
7 *
8 * Many thanks to Brian Gladman for his portable header files.
9 *
10 * To port Skein to an "unsupported" platform, change the definitions
11 * in this file appropriately.
12 */
13/* Copyright 2013 Doug Whiting. This code is released to the public domain. */
14
15#ifndef	_SKEIN_PORT_H_
16#define	_SKEIN_PORT_H_
17
18#include <sys/types.h>	/* get integer type definitions */
19
20#ifndef	RotL_64
21#define	RotL_64(x, N)	(((x) << (N)) | ((x) >> (64 - (N))))
22#endif
23
24/*
25 * Skein is "natively" little-endian (unlike SHA-xxx), for optimal
26 * performance on x86 CPUs. The Skein code requires the following
27 * definitions for dealing with endianness:
28 *
29 *    SKEIN_NEED_SWAP:  0 for little-endian, 1 for big-endian
30 *    Skein_Put64_LSB_First
31 *    Skein_Get64_LSB_First
32 *    Skein_Swap64
33 *
34 * If SKEIN_NEED_SWAP is defined at compile time, it is used here
35 * along with the portable versions of Put64/Get64/Swap64, which
36 * are slow in general.
37 *
38 * Otherwise, an "auto-detect" of endianness is attempted below.
39 * If the default handling doesn't work well, the user may insert
40 * platform-specific code instead (e.g., for big-endian CPUs).
41 *
42 */
43#ifndef	SKEIN_NEED_SWAP		/* compile-time "override" for endianness? */
44
45#include <sys/isa_defs.h>	/* get endianness selection */
46
47#if	defined(_ZFS_BIG_ENDIAN)
48/* here for big-endian CPUs */
49#define	SKEIN_NEED_SWAP   (1)
50#else
51/* here for x86 and x86-64 CPUs (and other detected little-endian CPUs) */
52#define	SKEIN_NEED_SWAP   (0)
53#define	Skein_Put64_LSB_First(dst08, src64, bCnt) bcopy(src64, dst08, bCnt)
54#define	Skein_Get64_LSB_First(dst64, src08, wCnt) \
55	bcopy(src08, dst64, 8 * (wCnt))
56#endif
57
58#endif				/* ifndef SKEIN_NEED_SWAP */
59
60/*
61 * Provide any definitions still needed.
62 */
63#ifndef	Skein_Swap64	/* swap for big-endian, nop for little-endian */
64#if	SKEIN_NEED_SWAP
65#define	Skein_Swap64(w64)				\
66	(((((uint64_t)(w64)) & 0xFF) << 56) |		\
67	(((((uint64_t)(w64)) >> 8) & 0xFF) << 48) |	\
68	(((((uint64_t)(w64)) >> 16) & 0xFF) << 40) |	\
69	(((((uint64_t)(w64)) >> 24) & 0xFF) << 32) |	\
70	(((((uint64_t)(w64)) >> 32) & 0xFF) << 24) |	\
71	(((((uint64_t)(w64)) >> 40) & 0xFF) << 16) |	\
72	(((((uint64_t)(w64)) >> 48) & 0xFF) << 8) |	\
73	(((((uint64_t)(w64)) >> 56) & 0xFF)))
74#else
75#define	Skein_Swap64(w64)  (w64)
76#endif
77#endif				/* ifndef Skein_Swap64 */
78
79#ifndef	Skein_Put64_LSB_First
80static inline void
81Skein_Put64_LSB_First(uint8_t *dst, const uint64_t *src, size_t bCnt)
82{
83	/*
84	 * this version is fully portable (big-endian or little-endian),
85	 * but slow
86	 */
87	size_t n;
88
89	for (n = 0; n < bCnt; n++)
90		dst[n] = (uint8_t)(src[n >> 3] >> (8 * (n & 7)));
91}
92#endif				/* ifndef Skein_Put64_LSB_First */
93
94#ifndef	Skein_Get64_LSB_First
95static inline void
96Skein_Get64_LSB_First(uint64_t *dst, const uint8_t *src, size_t wCnt)
97{
98	/*
99	 * this version is fully portable (big-endian or little-endian),
100	 * but slow
101	 */
102	size_t n;
103
104	for (n = 0; n < 8 * wCnt; n += 8)
105		dst[n / 8] = (((uint64_t)src[n])) +
106		    (((uint64_t)src[n + 1]) << 8) +
107		    (((uint64_t)src[n + 2]) << 16) +
108		    (((uint64_t)src[n + 3]) << 24) +
109		    (((uint64_t)src[n + 4]) << 32) +
110		    (((uint64_t)src[n + 5]) << 40) +
111		    (((uint64_t)src[n + 6]) << 48) +
112		    (((uint64_t)src[n + 7]) << 56);
113}
114#endif				/* ifndef Skein_Get64_LSB_First */
115
116#endif	/* _SKEIN_PORT_H_ */
117