dlls/ntdll/large_int.c

   1 /*
   2  * Large integer functions
   3  *
   4  * Copyright 2000 Alexandre Julliard
   5  */
   6
   7 #include "winnt.h"
   8 #include "ntddk.h"
   9
  10 /*
  11  * Note: we use LONGLONG instead of LARGE_INTEGER, because
  12  * the latter is a structure and the calling convention for
  13  * returning a structure would not be binary-compatible.
  14  *
  15  * FIXME: for platforms that don't have a native LONGLONG type,
  16  * we should define LONGLONG as a structure similar to LARGE_INTEGER
  17  * and do everything by hand. You are welcome to do it...
  18  */
  19
  20 /******************************************************************************
  21  *        RtlLargeIntegerAdd   (NTDLL.@)
  22  */
  23 LONGLONG WINAPI RtlLargeIntegerAdd( LONGLONG a, LONGLONG b )
  24 {
  25     return a + b;
  26 }
  27
  28
  29 /******************************************************************************
  30  *        RtlLargeIntegerSubtract   (NTDLL.@)
  31  */
  32 LONGLONG WINAPI RtlLargeIntegerSubtract( LONGLONG a, LONGLONG b )
  33 {
  34     return a - b;
  35 }
  36
  37
  38 /******************************************************************************
  39  *        RtlLargeIntegerNegate   (NTDLL.@)
  40  */
  41 LONGLONG WINAPI RtlLargeIntegerNegate( LONGLONG a )
  42 {
  43     return -a;
  44 }
  45
  46
  47 /******************************************************************************
  48  *        RtlLargeIntegerShiftLeft   (NTDLL.@)
  49  */
  50 LONGLONG WINAPI RtlLargeIntegerShiftLeft( LONGLONG a, INT count )
  51 {
  52     return a << count;
  53 }
  54
  55
  56 /******************************************************************************
  57  *        RtlLargeIntegerShiftRight   (NTDLL.@)
  58  */
  59 LONGLONG WINAPI RtlLargeIntegerShiftRight( LONGLONG a, INT count )
  60 {
  61     return (ULONGLONG)a >> count;
  62 }
  63
  64
  65 /******************************************************************************
  66  *        RtlLargeIntegerArithmeticShift   (NTDLL.@)
  67  */
  68 LONGLONG WINAPI RtlLargeIntegerArithmeticShift( LONGLONG a, INT count )
  69 {
  70     /* FIXME: gcc does arithmetic shift here, but it may not be true on all platforms */
  71     return a >> count;
  72 }
  73
  74
  75 /******************************************************************************
  76  *        RtlLargeIntegerDivide   (NTDLL.@)
  77  *
  78  * FIXME: should it be signed division instead?
  79  */
  80 ULONGLONG WINAPI RtlLargeIntegerDivide( ULONGLONG a, ULONGLONG b, ULONGLONG *rem )
  81 {
  82     ULONGLONG ret = a / b;
  83     if (rem) *rem = a - ret * b;
  84     return ret;
  85 }
  86
  87
  88 /******************************************************************************
  89  *        RtlConvertLongToLargeInteger   (NTDLL.@)
  90  */
  91 LONGLONG WINAPI RtlConvertLongToLargeInteger( LONG a )
  92 {
  93     return a;
  94 }
  95
  96
  97 /******************************************************************************
  98  *        RtlConvertUlongToLargeInteger   (NTDLL.@)
  99  */
 100 ULONGLONG WINAPI RtlConvertUlongToLargeInteger( ULONG a )
 101 {
 102     return a;
 103 }
 104
 105
 106 /******************************************************************************
 107  *        RtlEnlargedIntegerMultiply   (NTDLL.@)
 108  */
 109 LONGLONG WINAPI RtlEnlargedIntegerMultiply( INT a, INT b )
 110 {
 111     return (LONGLONG)a * b;
 112 }
 113
 114
 115 /******************************************************************************
 116  *        RtlEnlargedUnsignedMultiply   (NTDLL.@)
 117  */
 118 ULONGLONG WINAPI RtlEnlargedUnsignedMultiply( UINT a, UINT b )
 119 {
 120     return (ULONGLONG)a * b;
 121 }
 122
 123
 124 /******************************************************************************
 125  *        RtlEnlargedUnsignedDivide   (NTDLL.@)
 126  */
 127 UINT WINAPI RtlEnlargedUnsignedDivide( ULONGLONG a, UINT b, UINT *remptr )
 128 {
 129 #if defined(__i386__) && defined(__GNUC__)
 130     UINT ret, rem;
 131     __asm__("div %4,%%eax"
 132             : "=a" (ret), "=d" (rem)
 133             : "0" (*(UINT*)&a), "1" (*((UINT*)&a+1)), "g" (b) );
 134     if (remptr) *remptr = rem;
 135     return ret;
 136 #else
 137     UINT ret = a / b;
 138     if (remptr) *remptr = a % b;
 139     return ret;
 140 #endif
 141 }
 142
 143
 144 /******************************************************************************
 145  *        RtlExtendedLargeIntegerDivide   (NTDLL.@)
 146  */
 147 LONGLONG WINAPI RtlExtendedLargeIntegerDivide( LONGLONG a, INT b, INT *rem )
 148 {
 149     LONGLONG ret = a / b;
 150     if (rem) *rem = a - b * ret;
 151     return ret;
 152 }
 153
 154
 155 /******************************************************************************
 156  *        RtlExtendedIntegerMultiply   (NTDLL.@)
 157  */
 158 LONGLONG WINAPI RtlExtendedIntegerMultiply( LONGLONG a, INT b )
 159 {
 160     return a * b;
 161 }
 162
 163
 164 /******************************************************************************
 165  *        RtlExtendedMagicDivide   (NTDLL.@)
 166  *
 167  * This function computes (a * b) >> (64 + shift)
 168  *
 169  * This allows replacing a division by a longlong constant
 170  * by a multiplication by the inverse constant.
 171  *
 172  * If 'c' is the constant divisor, the constants 'b' and 'shift'
 173  * must be chosen such that b = 2^(64+shift) / c.
 174  * Then we have RtlExtendedMagicDivide(a,b,shift) == a * b / 2^(64+shift) == a / c.
 175  *
 176  * I'm too lazy to implement it right now...
 177  */
 178 /* LONGLONG WINAPI RtlExtendedMagicDivide( LONGLONG a, LONGLONG b, INT shift )
 179  * {
 180  *     return 0;
 181  * }
 182  */
 183
 184
 185 /******************************************************************************
 186  *        _alldiv   (NTDLL.@)
 187  */
 188 LONGLONG WINAPI _alldiv( LONGLONG a, LONGLONG b )
 189 {
 190     return a / b;
 191 }
 192
 193
 194 /******************************************************************************
 195  *        _allmul   (NTDLL.@)
 196  */
 197 LONGLONG WINAPI _allmul( LONGLONG a, LONGLONG b )
 198 {
 199     return a * b;
 200 }
 201
 202
 203 /******************************************************************************
 204  *        _allrem   (NTDLL.@)
 205  */
 206 LONGLONG WINAPI _allrem( LONGLONG a, LONGLONG b )
 207 {
 208     return a % b;
 209 }
 210
 211
 212 /******************************************************************************
 213  *        _aulldiv   (NTDLL.@)
 214  */
 215 ULONGLONG WINAPI _aulldiv( ULONGLONG a, ULONGLONG b )
 216 {
 217     return a / b;
 218 }
 219
 220
 221 /******************************************************************************
 222  *        _aullrem   (NTDLL.@)
 223  */
 224 ULONGLONG WINAPI _aullrem( ULONGLONG a, ULONGLONG b )
 225 {
 226     return a % b;
 227 }