dlls/ntdll/large_int.c

   1 /*
   2  * Large integer functions
   3  *
   4  * Copyright 2000 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "winnt.h"
  22 #include "ntddk.h"
  23
  24 /*
  25  * Note: we use LONGLONG instead of LARGE_INTEGER, because
  26  * the latter is a structure and the calling convention for
  27  * returning a structure would not be binary-compatible.
  28  *
  29  * FIXME: for platforms that don't have a native LONGLONG type,
  30  * we should define LONGLONG as a structure similar to LARGE_INTEGER
  31  * and do everything by hand. You are welcome to do it...
  32  */
  33
  34 /******************************************************************************
  35  *        RtlLargeIntegerAdd   (NTDLL.@)
  36  */
  37 LONGLONG WINAPI RtlLargeIntegerAdd( LONGLONG a, LONGLONG b )
  38 {
  39     return a + b;
  40 }
  41
  42
  43 /******************************************************************************
  44  *        RtlLargeIntegerSubtract   (NTDLL.@)
  45  */
  46 LONGLONG WINAPI RtlLargeIntegerSubtract( LONGLONG a, LONGLONG b )
  47 {
  48     return a - b;
  49 }
  50
  51
  52 /******************************************************************************
  53  *        RtlLargeIntegerNegate   (NTDLL.@)
  54  */
  55 LONGLONG WINAPI RtlLargeIntegerNegate( LONGLONG a )
  56 {
  57     return -a;
  58 }
  59
  60
  61 /******************************************************************************
  62  *        RtlLargeIntegerShiftLeft   (NTDLL.@)
  63  */
  64 LONGLONG WINAPI RtlLargeIntegerShiftLeft( LONGLONG a, INT count )
  65 {
  66     return a << count;
  67 }
  68
  69
  70 /******************************************************************************
  71  *        RtlLargeIntegerShiftRight   (NTDLL.@)
  72  */
  73 LONGLONG WINAPI RtlLargeIntegerShiftRight( LONGLONG a, INT count )
  74 {
  75     return (ULONGLONG)a >> count;
  76 }
  77
  78
  79 /******************************************************************************
  80  *        RtlLargeIntegerArithmeticShift   (NTDLL.@)
  81  */
  82 LONGLONG WINAPI RtlLargeIntegerArithmeticShift( LONGLONG a, INT count )
  83 {
  84     /* FIXME: gcc does arithmetic shift here, but it may not be true on all platforms */
  85     return a >> count;
  86 }
  87
  88
  89 /******************************************************************************
  90  *        RtlLargeIntegerDivide   (NTDLL.@)
  91  *
  92  * FIXME: should it be signed division instead?
  93  */
  94 ULONGLONG WINAPI RtlLargeIntegerDivide( ULONGLONG a, ULONGLONG b, ULONGLONG *rem )
  95 {
  96     ULONGLONG ret = a / b;
  97     if (rem) *rem = a - ret * b;
  98     return ret;
  99 }
 100
 101
 102 /******************************************************************************
 103  *        RtlConvertLongToLargeInteger   (NTDLL.@)
 104  */
 105 LONGLONG WINAPI RtlConvertLongToLargeInteger( LONG a )
 106 {
 107     return a;
 108 }
 109
 110
 111 /******************************************************************************
 112  *        RtlConvertUlongToLargeInteger   (NTDLL.@)
 113  */
 114 ULONGLONG WINAPI RtlConvertUlongToLargeInteger( ULONG a )
 115 {
 116     return a;
 117 }
 118
 119
 120 /******************************************************************************
 121  *        RtlEnlargedIntegerMultiply   (NTDLL.@)
 122  */
 123 LONGLONG WINAPI RtlEnlargedIntegerMultiply( INT a, INT b )
 124 {
 125     return (LONGLONG)a * b;
 126 }
 127
 128
 129 /******************************************************************************
 130  *        RtlEnlargedUnsignedMultiply   (NTDLL.@)
 131  */
 132 ULONGLONG WINAPI RtlEnlargedUnsignedMultiply( UINT a, UINT b )
 133 {
 134     return (ULONGLONG)a * b;
 135 }
 136
 137
 138 /******************************************************************************
 139  *        RtlEnlargedUnsignedDivide   (NTDLL.@)
 140  */
 141 UINT WINAPI RtlEnlargedUnsignedDivide( ULONGLONG a, UINT b, UINT *remptr )
 142 {
 143 #if defined(__i386__) && defined(__GNUC__)
 144     UINT ret, rem;
 145     __asm__("div %4,%%eax"
 146             : "=a" (ret), "=d" (rem)
 147             : "0" (*(UINT*)&a), "1" (*((UINT*)&a+1)), "g" (b) );
 148     if (remptr) *remptr = rem;
 149     return ret;
 150 #else
 151     UINT ret = a / b;
 152     if (remptr) *remptr = a % b;
 153     return ret;
 154 #endif
 155 }
 156
 157
 158 /******************************************************************************
 159  *        RtlExtendedLargeIntegerDivide   (NTDLL.@)
 160  */
 161 LONGLONG WINAPI RtlExtendedLargeIntegerDivide( LONGLONG a, INT b, INT *rem )
 162 {
 163     LONGLONG ret = a / b;
 164     if (rem) *rem = a - b * ret;
 165     return ret;
 166 }
 167
 168
 169 /******************************************************************************
 170  *        RtlExtendedIntegerMultiply   (NTDLL.@)
 171  */
 172 LONGLONG WINAPI RtlExtendedIntegerMultiply( LONGLONG a, INT b )
 173 {
 174     return a * b;
 175 }
 176
 177
 178 /******************************************************************************
 179  *        RtlExtendedMagicDivide   (NTDLL.@)
 180  *
 181  * This function computes (a * b) >> (64 + shift)
 182  *
 183  * This allows replacing a division by a longlong constant
 184  * by a multiplication by the inverse constant.
 185  *
 186  * If 'c' is the constant divisor, the constants 'b' and 'shift'
 187  * must be chosen such that b = 2^(64+shift) / c.
 188  * Then we have RtlExtendedMagicDivide(a,b,shift) == a * b / 2^(64+shift) == a / c.
 189  *
 190  * I'm too lazy to implement it right now...
 191  */
 192 /* LONGLONG WINAPI RtlExtendedMagicDivide( LONGLONG a, LONGLONG b, INT shift )
 193  * {
 194  *     return 0;
 195  * }
 196  */
 197
 198
 199 /******************************************************************************
 200  *        _alldiv   (NTDLL.@)
 201  */
 202 LONGLONG WINAPI _alldiv( LONGLONG a, LONGLONG b )
 203 {
 204     return a / b;
 205 }
 206
 207
 208 /******************************************************************************
 209  *        _allmul   (NTDLL.@)
 210  */
 211 LONGLONG WINAPI _allmul( LONGLONG a, LONGLONG b )
 212 {
 213     return a * b;
 214 }
 215
 216
 217 /******************************************************************************
 218  *        _allrem   (NTDLL.@)
 219  */
 220 LONGLONG WINAPI _allrem( LONGLONG a, LONGLONG b )
 221 {
 222     return a % b;
 223 }
 224
 225
 226 /******************************************************************************
 227  *        _aulldiv   (NTDLL.@)
 228  */
 229 ULONGLONG WINAPI _aulldiv( ULONGLONG a, ULONGLONG b )
 230 {
 231     return a / b;
 232 }
 233
 234
 235 /******************************************************************************
 236  *        _aullrem   (NTDLL.@)
 237  */
 238 ULONGLONG WINAPI _aullrem( ULONGLONG a, ULONGLONG b )
 239 {
 240     return a % b;
 241 }