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 u64lt(x, y) ((x) < (y))
  35 # define u64and(x, y) ((x) & (y))
  36 # define u64or(x, y) ((x) | (y))
  37 # define u64xor(x, y) ((x) ^ (y))
  38 # define u64plus(x, y) ((x) + (y))
  39 # define u64shl(x, n) ((x) << (n))
  40 # define u64shr(x, n) ((x) >> (n))
  41
  42 #else
  43
  44 /* u64 is a 64-bit unsigned integer value.
  45    u64init (HI, LO), is like u64hilo (HI, LO), but for use in
  46    initializer contexts.  */
  47 # ifdef WORDS_BIGENDIAN
  48 typedef struct { uint32_t hi, lo; } u64;
  49 #  define u64init(hi, lo) { hi, lo }
  50 # else
  51 typedef struct { uint32_t lo, hi; } u64;
  52 #  define u64init(hi, lo) { lo, hi }
  53 # endif
  54
  55 /* Given the high and low-order 32-bit quantities HI and LO, return a u64
  56    value representing (HI << 32) + LO.  */
  57 static inline u64
  58 u64hilo (uint32_t hi, uint32_t lo)
  59 {
  60   u64 r;
  61   r.hi = hi;
  62   r.lo = lo;
  63   return r;
  64 }
  65
  66 /* Return a u64 value representing LO.  */
  67 static inline u64
  68 u64lo (uint32_t lo)
  69 {
  70   u64 r;
  71   r.hi = 0;
  72   r.lo = lo;
  73   return r;
  74 }
  75
  76 /* Return X < Y.  */
  77 static inline int
  78 u64lt (u64 x, u64 y)
  79 {
  80   return x.hi < y.hi || (x.hi == y.hi && x.lo < y.lo);
  81 }
  82
  83 /* Return X & Y.  */
  84 static inline u64
  85 u64and (u64 x, u64 y)
  86 {
  87   u64 r;
  88   r.hi = x.hi & y.hi;
  89   r.lo = x.lo & y.lo;
  90   return r;
  91 }
  92
  93 /* Return X | Y.  */
  94 static inline u64
  95 u64or (u64 x, u64 y)
  96 {
  97   u64 r;
  98   r.hi = x.hi | y.hi;
  99   r.lo = x.lo | y.lo;
 100   return r;
 101 }
 102
 103 /* Return X ^ Y.  */
 104 static inline u64
 105 u64xor (u64 x, u64 y)
 106 {
 107   u64 r;
 108   r.hi = x.hi ^ y.hi;
 109   r.lo = x.lo ^ y.lo;
 110   return r;
 111 }
 112
 113 /* Return X + Y.  */
 114 static inline u64
 115 u64plus (u64 x, u64 y)
 116 {
 117   u64 r;
 118   r.lo = x.lo + y.lo;
 119   r.hi = x.hi + y.hi + (r.lo < x.lo);
 120   return r;
 121 }
 122
 123 /* Return X << N.  */
 124 static inline u64
 125 u64shl (u64 x, int n)
 126 {
 127   u64 r;
 128   if (n < 32)
 129     {
 130       r.hi = (x.hi << n) | (x.lo >> (32 - n));
 131       r.lo = x.lo << n;
 132     }
 133   else
 134     {
 135       r.hi = x.lo << (n - 32);
 136       r.lo = 0;
 137     }
 138   return r;
 139 }
 140
 141 /* Return X >> N.  */
 142 static inline u64
 143 u64shr (u64 x, int n)
 144 {
 145   u64 r;
 146   if (n < 32)
 147     {
 148       r.hi = x.hi >> n;
 149       r.lo = (x.hi << (32 - n)) | (x.lo >> n);
 150     }
 151   else
 152     {
 153       r.hi = 0;
 154       r.lo = x.hi >> (n - 32);
 155     }
 156   return r;
 157 }
 158
 159 #endif