reactos/lib/rtl/i386/random_asm.S

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS kernel
   4  * FILE:  ranom.asm
   5  * PURPOSE:         Random number generator functions
   6  * PROGRAMMER:      Magnus Olsen (magnusolsen@greatlord.com)
   7  * UPDATE HISTORY:
   8  *        Created 27/07/2005
   9  */
  10
  11 .intel_syntax noprefix
  12
  13 /* GLOBALS ****************************************************************/
  14
  15 .globl _RtlRandom@4         // [1] (no bug) (max optimze code)
  16 .globl _RtlUniform@4    // [2] (no bug) (max optimze code)
  17 .globl _SavedValue      // [3] (no bug) (max optimze code)
  18
  19 /* FUNCTIONS ***************************************************************/
  20
  21 _RtlRandom@4:
  22     // load pointer
  23     mov ecx,[esp+4]
  24     mov eax,[ecx]
  25
  26     // Result = *Seed * 0xffffffed + 0x7fffffc3 // take now 3 cycles
  27     lea edx,[eax + eax * 8]
  28
  29     lea eax,[eax + edx * 2 + 2147483709 ]  //  + 2147483709
  30     neg eax
  31
  32     cmp eax,-1
  33         je      .RtlRandom_Rand1
  34         cmp     eax, 2147483646
  35         je      .RtlRandom_Rand1
  36
  37         cmp     eax, 2147483647
  38         je      .RtlRandom_Rand2
  39
  40     test eax,eax
  41     jns .RtlRandom_Rand3
  42
  43     // else {
  44         mov     edx,eax
  45         and     edx,1
  46         add     eax,edx
  47     and eax,2147483647
  48     mov [ecx],eax
  49     jmp .RtlRandom_Seed
  50
  51 .RtlRandom_Rand1:
  52     // if (Result == 0xffffffff || Result == 0x7ffffffe)
  53     add eax, 2
  54     and eax, 2147483647
  55     mov [ecx],eax
  56     jmp .RtlRandom_Seed
  57
  58 .RtlRandom_Rand2:
  59     // else if (Result == 0x7fffffff)
  60     xor eax,eax
  61     mov [ecx],eax
  62     jmp .RtlRandom_Seed
  63
  64 .RtlRandom_Rand3:
  65     // else if ((Result & 0x80000000) == 0)
  66     mov  edx,eax
  67     xor edx,-1  // not edx  lock all clock until it finsish, but xor does not do that
  68     and edx,1
  69     add eax,edx
  70     mov [ecx],eax
  71
  72 .RtlRandom_Seed:
  73     mov eax,[ecx]
  74
  75     // Result = *Seed * 0xffffffed + 0x7fffffc3 // take now 3 cycles
  76     lea edx,[eax + eax * 8]
  77
  78     lea eax,[eax + edx * 2 + 2147483709 ]  //  + 2147483709   09-18
  79     neg eax
  80
  81     cmp eax,-1
  82         je      .RtlRandom_Seed1
  83         cmp     eax, 2147483646
  84         je      .RtlRandom_Seed1
  85
  86         cmp     eax, 2147483647
  87         je      .RtlRandom_Seed2
  88
  89     test eax,eax
  90     jns .RtlRandom_Seed3
  91
  92     // else {
  93     mov edx,eax
  94         and     edx,1
  95         add     eax,edx
  96     and eax,2147483647
  97
  98     // end
  99     mov edx,[ecx]
 100     mov [ecx],eax
 101
 102     mov ecx,eax // pos
 103     and ecx, 0x7f // pos = seed & 0x7f
 104     mov eax,ecx//
 105     mov eax, [_SavedValue + ecx*4]
 106     mov [_SavedValue + ecx*4], edx
 107     ret 4
 108
 109 .RtlRandom_Seed1:
 110     // if (Result == 0xffffffff || Result == 0x7ffffffe)
 111     add eax, 2
 112     and eax, 2147483647
 113
 114     // end
 115     mov edx,[ecx]
 116     mov [ecx],eax
 117
 118     mov ecx,eax // pos
 119     and ecx, 0x7f // pos = seed & 0x7f
 120     mov eax,ecx//
 121     mov eax, [_SavedValue + ecx*4]
 122     mov [_SavedValue + ecx*4], edx
 123     ret 4
 124
 125 .RtlRandom_Seed2:
 126     // else if (Result == 0x7fffffff)
 127     xor eax,eax
 128
 129     // end
 130     mov edx,[ecx]
 131     mov [ecx],eax
 132
 133     mov ecx,eax // pos
 134     and ecx, 0x7f // pos = seed & 0x7f
 135     mov eax,ecx//
 136     mov eax, [_SavedValue + ecx*4]
 137     mov [_SavedValue + ecx*4], edx
 138     ret 4
 139
 140 .RtlRandom_Seed3:
 141     // else if ((Result & 0x80000000) == 0)
 142     mov  edx,eax
 143     xor edx,-1  // not edx  lock all clock until it finsish, but xor does not do that
 144     and edx,1
 145     add eax,edx
 146
 147     // end
 148     mov edx,[ecx]
 149     mov [ecx],eax
 150
 151     mov ecx,eax // pos
 152     and ecx, 0x7f // pos = seed & 0x7f
 153     mov eax,ecx//
 154     mov eax, [_SavedValue + ecx*4]
 155     mov [_SavedValue + ecx*4], edx
 156     ret 4
 157
 158 // prototype: ULONG STDCALL RtlUniform (PULONG Seed)
 159 _RtlUniform@4:
 160     // load pointer
 161     mov ecx,[esp+4]
 162     mov eax,[ecx]
 163
 164     // Result = *Seed * 0xffffffed + 0x7fffffc3 // take now 3 cycles
 165     lea edx,[eax + eax * 8]
 166
 167     lea eax,[eax + edx * 2 + 2147483709 ]  //  + 2147483709   09-18
 168     neg eax
 169
 170     cmp eax,-1
 171         je      .RtlUniform_jump1
 172         cmp     eax, 2147483646
 173         je      .RtlUniform_jump1
 174
 175         cmp     eax, 2147483647
 176         je      .RtlUniform_jump2
 177
 178     test eax,eax
 179     jns .RtlUniform_jump3
 180
 181     // else {
 182         mov     edx,eax
 183         and     edx,1
 184         add     eax,edx
 185     and eax,2147483647
 186     mov [ecx],eax
 187     ret 4
 188
 189 .RtlUniform_jump1:
 190     // if (Result == 0xffffffff || Result == 0x7ffffffe)
 191     add eax, 2
 192     and eax, 2147483647
 193     mov [ecx],eax
 194     ret 4
 195
 196 .RtlUniform_jump2:
 197     // else if (Result == 0x7fffffff)
 198     xor eax,eax
 199     mov [ecx],eax
 200     ret 4
 201
 202 .RtlUniform_jump3:
 203     // else if ((Result & 0x80000000) == 0)
 204     mov  edx,eax
 205     xor edx,-1  // not edx  lock all clock until it finsish, but xor does not do that
 206     and edx,1
 207     add eax,edx
 208     mov [ecx],eax
 209     ret 4
 210
 211 .data
 212 // SavedValue[128]
 213 _SavedValue:
 214     .long 0x4c8bc0aa, 0x4c022957, 0x2232827a, 0x2f1e7626
 215         .long 0x7f8bdafb, 0x5c37d02a, 0x0ab48f72, 0x2f0c4ffa
 216         .long 0x290e1954, 0x6b635f23, 0x5d3885c0, 0x74b49ff8
 217         .long 0x5155fa54, 0x6214ad3f, 0x111e9c29, 0x242a3a09
 218         .long 0x75932ae1, 0x40ac432e, 0x54f7ba7a, 0x585ccbd5
 219         .long 0x6df5c727, 0x0374dad1, 0x7112b3f1, 0x735fc311
 220         .long 0x404331a9, 0x74d97781, 0x64495118, 0x323e04be
 221         .long 0x5974b425, 0x4862e393, 0x62389c1d, 0x28a68b82
 222         .long 0x0f95da37, 0x7a50bbc6, 0x09b0091c, 0x22cdb7b4
 223         .long 0x4faaed26, 0x66417ccd, 0x189e4bfa, 0x1ce4e8dd
 224         .long 0x5274c742, 0x3bdcf4dc, 0x2d94e907, 0x32eac016
 225         .long 0x26d33ca3, 0x60415a8a, 0x31f57880, 0x68c8aa52
 226         .long 0x23eb16da, 0x6204f4a1, 0x373927c1, 0x0d24eb7c
 227         .long 0x06dd7379, 0x2b3be507, 0x0f9c55b1, 0x2c7925eb
 228         .long 0x36d67c9a, 0x42f831d9, 0x5e3961cb, 0x65d637a8
 229         .long 0x24bb3820, 0x4d08e33d, 0x2188754f, 0x147e409e
 230         .long 0x6a9620a0, 0x62e26657, 0x7bd8ce81, 0x11da0abb
 231         .long 0x5f9e7b50, 0x23e444b6, 0x25920c78, 0x5fc894f0
 232         .long 0x5e338cbb, 0x404237fd, 0x1d60f80f, 0x320a1743
 233         .long 0x76013d2b, 0x070294ee, 0x695e243b, 0x56b177fd
 234         .long 0x752492e1, 0x6decd52f, 0x125f5219, 0x139d2e78
 235         .long 0x1898d11e, 0x2f7ee785, 0x4db405d8, 0x1a028a35
 236         .long 0x63f6f323, 0x1f6d0078, 0x307cfd67, 0x3f32a78a
 237         .long 0x6980796c, 0x462b3d83, 0x34b639f2, 0x53fce379
 238         .long 0x74ba50f4, 0x1abc2c4b, 0x5eeaeb8d, 0x335a7a0d
 239         .long 0x3973dd20, 0x0462d66b, 0x159813ff, 0x1e4643fd
 240         .long 0x06bc5c62, 0x3115e3fc, 0x09101613, 0x47af2515
 241         .long 0x4f11ec54, 0x78b99911, 0x3db8dd44, 0x1ec10b9b
 242         .long 0x5b5506ca, 0x773ce092, 0x567be81a, 0x5475b975
 243         .long 0x7a2cde1a, 0x494536f5, 0x34737bb4, 0x76d9750b
 244         .long 0x2a1f6232, 0x2e49644d, 0x7dddcbe7, 0x500cebdb
 245         .long 0x619dab9e, 0x48c626fe, 0x1cda3193, 0x52dabe9d