mdw@git.distorted.org.uk Git - secnet/blob - u64.h

   1 /* uint64_t-like operations that work even on hosts lacking uint64_t
   2
   3    Copyright (C) 2006, 2009, 2010 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation, either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #include <stddef.h>
  21 #include <stdint.h>
  22
  23 /* Return X rotated left by N bits, where 0 < N < 64.  */
  24 #define u64rol(x, n) u64or (u64shl (x, n), u64shr (x, 64 - n))
  25
  26 #ifdef UINT64_MAX
  27
  28 /* Native implementations are trivial.  See below for comments on what
  29    these operations do.  */
  30 typedef uint64_t u64;
  31 # define u64hilo(hi, lo) ((u64) (((u64) (hi) << 32) + (lo)))
  32 # define u64init(hi, lo) u64hilo (hi, lo)
  33 # define u64lo(x) ((u64) (x))
  34 # define u64getlo(x) ((x)&0xffffffffu)
  35 # define u64gethi(x) (((u64) (x) >> 32) & 0xffffffffu)
  36 # define u64lt(x, y) ((x) < (y))
  37 # define u64and(x, y) ((x) & (y))
  38 # define u64or(x, y) ((x) | (y))
  39 # define u64xor(x, y) ((x) ^ (y))
  40 # define u64not(x) (~(x))
  41 # define u64plus(x, y) ((x) + (y))
  42 # define u64shl(x, n) ((x) << (n))
  43 # define u64shr(x, n) ((x) >> (n))
  44
  45 #else
  46
  47 /* u64 is a 64-bit unsigned integer value.
  48    u64init (HI, LO), is like u64hilo (HI, LO), but for use in
  49    initializer contexts.  */
  50 # ifdef WORDS_BIGENDIAN
  51 typedef struct { uint32_t hi, lo; } u64;
  52 #  define u64init(hi, lo) { hi, lo }
  53 # else
  54 typedef struct { uint32_t lo, hi; } u64;
  55 #  define u64init(hi, lo) { lo, hi }
  56 # endif
  57
  58 /* Given the high and low-order 32-bit quantities HI and LO, return a u64
  59    value representing (HI << 32) + LO.  */
  60 static inline u64
  61 u64hilo (uint32_t hi, uint32_t lo)
  62 {
  63   u64 r;
  64   r.hi = hi;
  65   r.lo = lo;
  66   return r;
  67 }
  68
  69 /* Return a u64 value representing LO.  */
  70 static inline u64
  71 u64lo (uint32_t lo)
  72 {
  73   u64 r;
  74   r.hi = 0;
  75   r.lo = lo;
  76   return r;
  77 }
  78
  79 /* Return the high and low halves of X. */
  80 # define u64getlo(x) ((x).lo)
  81 # define u64gethi(x) ((x).hi)
  82
  83 /* Return X < Y.  */
  84 static inline int
  85 u64lt (u64 x, u64 y)
  86 {
  87   return x.hi < y.hi || (x.hi == y.hi && x.lo < y.lo);
  88 }
  89
  90 /* Return X & Y.  */
  91 static inline u64
  92 u64and (u64 x, u64 y)
  93 {
  94   u64 r;
  95   r.hi = x.hi & y.hi;
  96   r.lo = x.lo & y.lo;
  97   return r;
  98 }
  99
 100 /* Return X | Y.  */
 101 static inline u64
 102 u64or (u64 x, u64 y)
 103 {
 104   u64 r;
 105   r.hi = x.hi | y.hi;
 106   r.lo = x.lo | y.lo;
 107   return r;
 108 }
 109
 110 /* Return X ^ Y.  */
 111 static inline u64
 112 u64xor (u64 x, u64 y)
 113 {
 114   u64 r;
 115   r.hi = x.hi ^ y.hi;
 116   r.lo = x.lo ^ y.lo;
 117   return r;
 118 }
 119
 120 /* Return ~X.  */
 121 static inline u64
 122 u64not (u64 x)
 123 {
 124   u64 r;
 125   r.hi = ~x.hi;
 126   r.lo = ~x.lo;
 127   return r;
 128 }
 129
 130 /* Return X + Y.  */
 131 static inline u64
 132 u64plus (u64 x, u64 y)
 133 {
 134   u64 r;
 135   r.lo = x.lo + y.lo;
 136   r.hi = x.hi + y.hi + (r.lo < x.lo);
 137   return r;
 138 }
 139
 140 /* Return X << N.  */
 141 static inline u64
 142 u64shl (u64 x, int n)
 143 {
 144   u64 r;
 145   if (n < 32)
 146     {
 147       r.hi = (x.hi << n) | (x.lo >> (32 - n));
 148       r.lo = x.lo << n;
 149     }
 150   else
 151     {
 152       r.hi = x.lo << (n - 32);
 153       r.lo = 0;
 154     }
 155   return r;
 156 }
 157
 158 /* Return X >> N.  */
 159 static inline u64
 160 u64shr (u64 x, int n)
 161 {
 162   u64 r;
 163   if (n < 32)
 164     {
 165       r.hi = x.hi >> n;
 166       r.lo = (x.hi << (32 - n)) | (x.lo >> n);
 167     }
 168   else
 169     {
 170       r.hi = 0;
 171       r.lo = x.hi >> (n - 32);
 172     }
 173   return r;
 174 }
 175
 176 #endif