sys/dev/random/uint128.h

   1 /*-
   2  * Copyright (c) 2015 Mark R V Murray
   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  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #ifndef SYS_DEV_RANDOM_UINT128_H_INCLUDED
  30 #define SYS_DEV_RANDOM_UINT128_H_INCLUDED
  31
  32 #include <sys/endian.h>
  33
  34 /* This whole thing is a crock :-(
  35  *
  36  * Everyone knows you always need the __uint128_t types!
  37  */
  38
  39 #ifdef __SIZEOF_INT128__
  40 #define USE_REAL_UINT128_T
  41 #endif
  42
  43 #ifdef USE_REAL_UINT128_T
  44 typedef __uint128_t uint128_t;
  45 #define UINT128_ZERO 0ULL
  46 #else
  47 typedef struct {
  48         /* Ignore endianness */
  49         uint64_t u128t_word0;
  50         uint64_t u128t_word1;
  51 } uint128_t;
  52 static const uint128_t very_long_zero = {0UL,0UL};
  53 #define UINT128_ZERO very_long_zero
  54 #endif
  55
  56 static __inline void
  57 uint128_increment(uint128_t *big_uintp)
  58 {
  59 #ifdef USE_REAL_UINT128_T
  60         (*big_uintp)++;
  61 #else
  62         big_uintp->u128t_word0++;
  63         if (big_uintp->u128t_word0 == 0UL)
  64                 big_uintp->u128t_word1++;
  65 #endif
  66 }
  67
  68 static __inline void
  69 uint128_add64(uint128_t *big_uintp, uint64_t add)
  70 {
  71 #ifdef USE_REAL_UINT128_T
  72         (*big_uintp) += add;
  73 #else
  74         uint64_t word0p;
  75
  76         word0p = big_uintp->u128t_word0 + add;
  77         if (word0p < big_uintp->u128t_word0)
  78                 big_uintp->u128t_word1++;
  79         big_uintp->u128t_word0 = word0p;
  80 #endif
  81 }
  82
  83 static __inline bool
  84 uint128_equals(uint128_t a, uint128_t b)
  85 {
  86 #ifdef USE_REAL_UINT128_T
  87         return (a == b);
  88 #else
  89         return (a.u128t_word0 == b.u128t_word0 &&
  90             a.u128t_word1 == b.u128t_word1);
  91 #endif
  92 }
  93
  94 static __inline int
  95 uint128_is_zero(uint128_t big_uint)
  96 {
  97         return (uint128_equals(big_uint, UINT128_ZERO));
  98 }
  99
 100 static __inline uint128_t
 101 le128dec(const void *pp)
 102 {
 103         const uint8_t *p = pp;
 104
 105 #ifdef USE_REAL_UINT128_T
 106         return (((uint128_t)le64dec(p + 8) << 64) | le64dec(p));
 107 #else
 108         return ((uint128_t){
 109             .u128t_word0 = le64dec(p),
 110             .u128t_word1 = le64dec(p + 8),
 111             });
 112 #endif
 113 }
 114
 115 static __inline void
 116 le128enc(void *pp, uint128_t u)
 117 {
 118         uint8_t *p = pp;
 119
 120 #ifdef USE_REAL_UINT128_T
 121         le64enc(p, (uint64_t)(u & UINT64_MAX));
 122         le64enc(p + 8, (uint64_t)(u >> 64));
 123 #else
 124         le64enc(p, u.u128t_word0);
 125         le64enc(p + 8, u.u128t_word1);
 126 #endif
 127 }
 128
 129 #endif /* SYS_DEV_RANDOM_UINT128_H_INCLUDED */