lib/ntdll/nasm/rtl/i386_RtlRandom.asm

   1 ; * base on ntdll/rtl/random.c v 1.1 2003/06/07 11:32:03
   2 ; *
   3 ; * COPYRIGHT:       See COPYING in the top level directory
   4 ; * PROJECT:         ReactOS kernel
   5 ; * FILE:            i386_RtlRandom.asm
   6 ; * PURPOSE:         Random number generator functions
   7 ; * PROGRAMMER:      Magnus Olsen (magnusolsen@greatlord.com)
   8 ; * UPDATE HISTORY:
   9 ; *                  Created 20/07-2003
  10 ; *
  11
  12
  13           BITS 32
  14         GLOBAL _RtlRandom@4     ; [1] (no bug) (max optimze code)
  15         GLOBAL _RtlUniform@4    ; [2] (no bug) (max optimze code)
  16         GLOBAL _SavedValue    ; [3] (no bug) (max optimze code)
  17           SECTION .text
  18
  19 _RtlRandom@4:
  20               ; load pointer
  21               mov ecx,[esp+4]
  22               mov eax,[ecx]
  23
  24  ; Result = *Seed * 0xffffffed + 0x7fffffc3 ; take now 3 cycles
  25               lea       edx,[eax + eax * 8]
  26
  27               lea eax,[eax + edx * 2 + 2147483709 ]  ;  + 2147483709
  28               neg       eax
  29
  30               cmp       eax,-1
  31                 je      .RtlRandom_Rand1
  32                 cmp     eax, 2147483646
  33                 je      .RtlRandom_Rand1
  34
  35                 cmp     eax, 2147483647
  36                 je      .RtlRandom_Rand2
  37
  38               test eax,eax
  39               jns .RtlRandom_Rand3
  40
  41              ; else {
  42                mov      edx,eax
  43                and      edx,1
  44                add      eax,edx
  45              and        eax,2147483647
  46              mov [ecx],eax
  47              jmp .RtlRandom_Seed
  48
  49
  50 .RtlRandom_Rand1:
  51               ; if (Result == 0xffffffff || Result == 0x7ffffffe)
  52               add eax, 2
  53               and eax, 2147483647
  54               mov [ecx],eax
  55               jmp .RtlRandom_Seed
  56
  57 .RtlRandom_Rand2:
  58               ; else if (Result == 0x7fffffff)
  59               xor eax,eax
  60               mov [ecx],eax
  61               jmp .RtlRandom_Seed
  62
  63 .RtlRandom_Rand3:
  64               ; else if ((Result & 0x80000000) == 0)
  65               mov  edx,eax
  66               xor edx,-1            ; not edx  lock all clock until it finsish, but xor does not do that
  67               and edx,1
  68               add eax,edx
  69               mov [ecx],eax
  70
  71 .RtlRandom_Seed:
  72               mov eax,[ecx]
  73
  74               ; Result = *Seed * 0xffffffed + 0x7fffffc3 ; take now 3 cycles
  75               lea       edx,[eax + eax * 8]
  76
  77               lea eax,[eax + edx * 2 + 2147483709 ]  ;  + 2147483709   09-18
  78               neg       eax
  79
  80               cmp       eax,-1
  81                 je      .RtlRandom_Seed1
  82                 cmp     eax, 2147483646
  83                 je      .RtlRandom_Seed1
  84
  85                 cmp     eax, 2147483647
  86                 je      .RtlRandom_Seed2
  87
  88               test eax,eax
  89               jns .RtlRandom_Seed3
  90
  91              ; else {
  92                mov      edx,eax
  93                and      edx,1
  94                add      eax,edx
  95              and        eax,2147483647
  96
  97               ; end
  98               mov edx,[ecx]
  99               mov [ecx],eax
 100
 101               mov ecx,eax ; pos
 102               and ecx, 0x7f ; pos = seed & 0x7f
 103               mov eax,ecx;
 104               mov eax, dword [_SavedValue + (ecx*4)]
 105               mov dword [_SavedValue + (ecx*4)], edx
 106               ret 4
 107
 108 .RtlRandom_Seed1:
 109               ; if (Result == 0xffffffff || Result == 0x7ffffffe)
 110               add eax, 2
 111               and eax, 2147483647
 112
 113               ; end
 114               mov edx,[ecx]
 115               mov [ecx],eax
 116
 117               mov ecx,eax ; pos
 118               and ecx, 0x7f ; pos = seed & 0x7f
 119               mov eax,ecx;
 120               mov eax, dword [_SavedValue + (ecx*4)]
 121               mov dword [_SavedValue + (ecx*4)], edx
 122               ret 4
 123
 124 .RtlRandom_Seed2:
 125               ; else if (Result == 0x7fffffff)
 126               xor eax,eax
 127
 128               ; end
 129               mov edx,[ecx]
 130               mov [ecx],eax
 131
 132               mov ecx,eax ; pos
 133               and ecx, 0x7f ; pos = seed & 0x7f
 134               mov eax,ecx;
 135               mov eax, dword [_SavedValue + (ecx*4)]
 136               mov dword [_SavedValue + (ecx*4)], edx
 137               ret 4
 138
 139 .RtlRandom_Seed3:
 140               ; else if ((Result & 0x80000000) == 0)
 141               mov  edx,eax
 142               xor edx,-1            ; not edx  lock all clock until it finsish, but xor does not do that
 143               and edx,1
 144               add eax,edx
 145
 146               ; end
 147               mov edx,[ecx]
 148               mov [ecx],eax
 149
 150               mov ecx,eax ; pos
 151               and ecx, 0x7f ; pos = seed & 0x7f
 152               mov eax,ecx;
 153               mov eax, dword [_SavedValue + (ecx*4)]
 154               mov dword [_SavedValue + (ecx*4)], edx
 155               ret 4
 156
 157
 158
 159
 160 ; prototype: ULONG STDCALL RtlUniform (PULONG Seed)
 161 _RtlUniform@4:
 162               ; load pointer
 163               mov ecx,[esp+4]
 164               mov eax,[ecx]
 165
 166               ; Result = *Seed * 0xffffffed + 0x7fffffc3 ; take now 3 cycles
 167               lea       edx,[eax + eax * 8]
 168
 169               lea eax,[eax + edx * 2 + 2147483709 ]  ;  + 2147483709   09-18
 170               neg       eax
 171
 172               cmp       eax,-1
 173                 je      .RtlUniform_jump1
 174                 cmp     eax, 2147483646
 175                 je      .RtlUniform_jump1
 176
 177                 cmp     eax, 2147483647
 178                 je      .RtlUniform_jump2
 179
 180               test eax,eax
 181               jns .RtlUniform_jump3
 182
 183              ; else {
 184                mov      edx,eax
 185                and      edx,1
 186                add      eax,edx
 187              and        eax,2147483647
 188              mov [ecx],eax
 189              ret 4
 190
 191 .RtlUniform_jump1:
 192               ; if (Result == 0xffffffff || Result == 0x7ffffffe)
 193               add eax, 2
 194               and eax, 2147483647
 195               mov [ecx],eax
 196               ret 4
 197
 198 .RtlUniform_jump2:
 199               ; else if (Result == 0x7fffffff)
 200               xor eax,eax
 201               mov [ecx],eax
 202               ret 4
 203
 204 .RtlUniform_jump3:
 205               ; else if ((Result & 0x80000000) == 0)
 206               mov  edx,eax
 207               xor edx,-1            ; not edx  lock all clock until it finsish, but xor does not do that
 208               and edx,1
 209               add eax,edx
 210               mov [ecx],eax
 211               ret 4
 212
 213
 214           SECTION .data
 215 ; SavedValue[128]
 216 _SavedValue:
 217             dd 0x4c8bc0aa, 0x4c022957, 0x2232827a, 0x2f1e7626
 218                 dd 0x7f8bdafb, 0x5c37d02a, 0x0ab48f72, 0x2f0c4ffa
 219                 dd 0x290e1954, 0x6b635f23, 0x5d3885c0, 0x74b49ff8
 220                 dd 0x5155fa54, 0x6214ad3f, 0x111e9c29, 0x242a3a09
 221                 dd 0x75932ae1, 0x40ac432e, 0x54f7ba7a, 0x585ccbd5
 222                 dd 0x6df5c727, 0x0374dad1, 0x7112b3f1, 0x735fc311
 223                 dd 0x404331a9, 0x74d97781, 0x64495118, 0x323e04be
 224                 dd 0x5974b425, 0x4862e393, 0x62389c1d, 0x28a68b82
 225                 dd 0x0f95da37, 0x7a50bbc6, 0x09b0091c, 0x22cdb7b4
 226                 dd 0x4faaed26, 0x66417ccd, 0x189e4bfa, 0x1ce4e8dd
 227                 dd 0x5274c742, 0x3bdcf4dc, 0x2d94e907, 0x32eac016
 228                 dd 0x26d33ca3, 0x60415a8a, 0x31f57880, 0x68c8aa52
 229                 dd 0x23eb16da, 0x6204f4a1, 0x373927c1, 0x0d24eb7c
 230                 dd 0x06dd7379, 0x2b3be507, 0x0f9c55b1, 0x2c7925eb
 231                 dd 0x36d67c9a, 0x42f831d9, 0x5e3961cb, 0x65d637a8
 232                 dd 0x24bb3820, 0x4d08e33d, 0x2188754f, 0x147e409e
 233                 dd 0x6a9620a0, 0x62e26657, 0x7bd8ce81, 0x11da0abb
 234                 dd 0x5f9e7b50, 0x23e444b6, 0x25920c78, 0x5fc894f0
 235                 dd 0x5e338cbb, 0x404237fd, 0x1d60f80f, 0x320a1743
 236                 dd 0x76013d2b, 0x070294ee, 0x695e243b, 0x56b177fd
 237                 dd 0x752492e1, 0x6decd52f, 0x125f5219, 0x139d2e78
 238                 dd 0x1898d11e, 0x2f7ee785, 0x4db405d8, 0x1a028a35
 239                 dd 0x63f6f323, 0x1f6d0078, 0x307cfd67, 0x3f32a78a
 240                 dd 0x6980796c, 0x462b3d83, 0x34b639f2, 0x53fce379
 241                 dd 0x74ba50f4, 0x1abc2c4b, 0x5eeaeb8d, 0x335a7a0d
 242                 dd 0x3973dd20, 0x0462d66b, 0x159813ff, 0x1e4643fd
 243                 dd 0x06bc5c62, 0x3115e3fc, 0x09101613, 0x47af2515
 244                 dd 0x4f11ec54, 0x78b99911, 0x3db8dd44, 0x1ec10b9b
 245                 dd 0x5b5506ca, 0x773ce092, 0x567be81a, 0x5475b975
 246                 dd 0x7a2cde1a, 0x494536f5, 0x34737bb4, 0x76d9750b
 247                 dd 0x2a1f6232, 0x2e49644d, 0x7dddcbe7, 0x500cebdb
 248                 dd 0x619dab9e, 0x48c626fe, 0x1cda3193, 0x52dabe9d
 249