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Diffstat (limited to 'comm/third_party/libgcrypt/cipher/bithelp.h')
-rw-r--r-- | comm/third_party/libgcrypt/cipher/bithelp.h | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/comm/third_party/libgcrypt/cipher/bithelp.h b/comm/third_party/libgcrypt/cipher/bithelp.h new file mode 100644 index 0000000000..7793ce7ca3 --- /dev/null +++ b/comm/third_party/libgcrypt/cipher/bithelp.h @@ -0,0 +1,123 @@ +/* bithelp.h - Some bit manipulation helpers + * Copyright (C) 1999, 2002 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this program; if not, see <http://www.gnu.org/licenses/>. + */ +#ifndef GCRYPT_BITHELP_H +#define GCRYPT_BITHELP_H + +#include "types.h" + + +/**************** + * Rotate the 32 bit unsigned integer X by N bits left/right + */ +static inline u32 rol(u32 x, int n) +{ + return ( (x << (n&(32-1))) | (x >> ((32-n)&(32-1))) ); +} + +static inline u32 ror(u32 x, int n) +{ + return ( (x >> (n&(32-1))) | (x << ((32-n)&(32-1))) ); +} + +static inline u64 rol64(u64 x, int n) +{ + return ( (x << (n&(64-1))) | (x >> ((64-n)&(64-1))) ); +} + +/* Byte swap for 32-bit and 64-bit integers. If available, use compiler + provided helpers. */ +#ifdef HAVE_BUILTIN_BSWAP32 +# define _gcry_bswap32 __builtin_bswap32 +#else +static inline u32 +_gcry_bswap32(u32 x) +{ + return ((rol(x, 8) & 0x00ff00ffL) | (ror(x, 8) & 0xff00ff00L)); +} +#endif + +#ifdef HAVE_BUILTIN_BSWAP64 +# define _gcry_bswap64 __builtin_bswap64 +#else +static inline u64 +_gcry_bswap64(u64 x) +{ + return ((u64)_gcry_bswap32(x) << 32) | (_gcry_bswap32(x >> 32)); +} +#endif + +/* Endian dependent byte swap operations. */ +#ifdef WORDS_BIGENDIAN +# define le_bswap32(x) _gcry_bswap32(x) +# define be_bswap32(x) ((u32)(x)) +# define le_bswap64(x) _gcry_bswap64(x) +# define be_bswap64(x) ((u64)(x)) +#else +# define le_bswap32(x) ((u32)(x)) +# define be_bswap32(x) _gcry_bswap32(x) +# define le_bswap64(x) ((u64)(x)) +# define be_bswap64(x) _gcry_bswap64(x) +#endif + + +/* Count trailing zero bits in an unsigend int. We return an int + because that is what gcc's builtin does. Returns the number of + bits in X if X is 0. */ +static inline int +_gcry_ctz (unsigned int x) +{ +#if defined (HAVE_BUILTIN_CTZ) + return x ? __builtin_ctz (x) : 8 * sizeof (x); +#else + /* See + * http://graphics.stanford.edu/~seander/bithacks.html#ZerosOnRightModLookup + */ + static const unsigned char mod37[] = + { + sizeof (unsigned int)*8, + 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13, + 4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9, + 5, 20, 8, 19, 18 + }; + return (int)mod37[(-x & x) % 37]; +#endif +} + + +/* Count trailing zero bits in an u64. We return an int because that + is what gcc's builtin does. Returns the number of bits in X if X + is 0. */ +static inline int +_gcry_ctz64(u64 x) +{ +#if defined (HAVE_BUILTIN_CTZL) && SIZEOF_UNSIGNED_LONG >= 8 + return x ? __builtin_ctzl (x) : 8 * sizeof (x); +#elif defined (HAVE_BUILTIN_CTZ) && SIZEOF_UNSIGNED_INT >= 8 +#warning hello + return x ? __builtin_ctz (x) : 8 * sizeof (x); +#else + if ((x & 0xffffffff)) + return _gcry_ctz (x); + else + return 32 + _gcry_ctz (x >> 32); +#endif +} + + +#endif /*GCRYPT_BITHELP_H*/ |