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 #include <sys/systm.h> /* for bcopy() */
20
21 #ifndef RotL_64
22 #define RotL_64(x, N) (((x) << (N)) | ((x) >> (64 - (N))))
23 #endif
24
25 /*
26 * Skein is "natively" little-endian (unlike SHA-xxx), for optimal
27 * performance on x86 CPUs. The Skein code requires the following
28 * definitions for dealing with endianness:
29 *
30 * SKEIN_NEED_SWAP: 0 for little-endian, 1 for big-endian
31 * Skein_Put64_LSB_First
32 * Skein_Get64_LSB_First
33 * Skein_Swap64
34 *
35 * If SKEIN_NEED_SWAP is defined at compile time, it is used here
36 * along with the portable versions of Put64/Get64/Swap64, which
37 * are slow in general.
38 *
39 * Otherwise, an "auto-detect" of endianness is attempted below.
40 * If the default handling doesn't work well, the user may insert
41 * platform-specific code instead (e.g., for big-endian CPUs).
42 *
43 */
44 #ifndef SKEIN_NEED_SWAP /* compile-time "override" for endianness? */
45
46 #include <sys/isa_defs.h> /* get endianness selection */
47
48 #define PLATFORM_MUST_ALIGN _ALIGNMENT_REQUIRED
49 #if defined(_BIG_ENDIAN)
50 /* here for big-endian CPUs */
51 #define SKEIN_NEED_SWAP (1)
52 #else
53 /* here for x86 and x86-64 CPUs (and other detected little-endian CPUs) */
54 #define SKEIN_NEED_SWAP (0)
55 #if PLATFORM_MUST_ALIGN == 0 /* ok to use "fast" versions? */
56 #define Skein_Put64_LSB_First(dst08, src64, bCnt) bcopy(src64, dst08, bCnt)
57 #define Skein_Get64_LSB_First(dst64, src08, wCnt) \
58 bcopy(src08, dst64, 8 * (wCnt))
59 #endif
60 #endif
61
62 #endif /* ifndef SKEIN_NEED_SWAP */
63
64 /*
65 * Provide any definitions still needed.
66 */
67 #ifndef Skein_Swap64 /* swap for big-endian, nop for little-endian */
68 #if SKEIN_NEED_SWAP
69 #define Skein_Swap64(w64) \
70 (((((uint64_t)(w64)) & 0xFF) << 56) | \
71 (((((uint64_t)(w64)) >> 8) & 0xFF) << 48) | \
72 (((((uint64_t)(w64)) >> 16) & 0xFF) << 40) | \
73 (((((uint64_t)(w64)) >> 24) & 0xFF) << 32) | \
74 (((((uint64_t)(w64)) >> 32) & 0xFF) << 24) | \
75 (((((uint64_t)(w64)) >> 40) & 0xFF) << 16) | \
76 (((((uint64_t)(w64)) >> 48) & 0xFF) << 8) | \
77 (((((uint64_t)(w64)) >> 56) & 0xFF)))
78 #else
79 #define Skein_Swap64(w64) (w64)
80 #endif
81 #endif /* ifndef Skein_Swap64 */
82
83 #ifndef Skein_Put64_LSB_First
84 void
85 Skein_Put64_LSB_First(uint8_t *dst, const uint64_t *src, size_t bCnt)
86 #ifdef SKEIN_PORT_CODE /* instantiate the function code here? */
87 {
88 /*
89 * this version is fully portable (big-endian or little-endian),
90 * but slow
91 */
92 size_t n;
93
94 for (n = 0; n < bCnt; n++)
95 dst[n] = (uint8_t)(src[n >> 3] >> (8 * (n & 7)));
96 }
97 #else
98 ; /* output only the function prototype */
99 #endif
100 #endif /* ifndef Skein_Put64_LSB_First */
101
102 #ifndef Skein_Get64_LSB_First
103 void
104 Skein_Get64_LSB_First(uint64_t *dst, const uint8_t *src, size_t wCnt)
105 #ifdef SKEIN_PORT_CODE /* instantiate the function code here? */
106 {
107 /*
108 * this version is fully portable (big-endian or little-endian),
109 * but slow
110 */
111 size_t n;
112
113 for (n = 0; n < 8 * wCnt; n += 8)
114 dst[n / 8] = (((uint64_t)src[n])) +
115 (((uint64_t)src[n + 1]) << 8) +
116 (((uint64_t)src[n + 2]) << 16) +
117 (((uint64_t)src[n + 3]) << 24) +
118 (((uint64_t)src[n + 4]) << 32) +
119 (((uint64_t)src[n + 5]) << 40) +
120 (((uint64_t)src[n + 6]) << 48) +
121 (((uint64_t)src[n + 7]) << 56);
122 }
123 #else
124 ; /* output only the function prototype */
125 #endif
126 #endif /* ifndef Skein_Get64_LSB_First */
127
128 #endif /* _SKEIN_PORT_H_ */