Algoritmo CRC32

include 'win32ax.inc'

.data
TLookup dd 0x0,0x77073096,0xEE0E612C,0x990951BA,0x76DC419,0x706AF48F,0xE963A535,\
          0x9E6495A3,0xEDB8832,0x79DCB8A4,0xE0D5E91E,0x97D2D988,0x9B64C2B,0x7EB17CBD,\
          0xE7B82D07,0x90BF1D91,0x1DB71064,0x6AB020F2,0xF3B97148,0x84BE41DE,0x1ADAD47D,\
          0x6DDDE4EB,0xF4D4B551,0x83D385C7,0x136C9856,0x646BA8C0,0xFD62F97A,0x8A65C9EC,\
          0x14015C4F,0x63066CD9,0xFA0F3D63,0x8D080DF5,0x3B6E20C8,0x4C69105E,0xD56041E4,\
          0xA2677172,0x3C03E4D1,0x4B04D447,0xD20D85FD,0xA50AB56B,0x35B5A8FA,0x42B2986C,\
          0xDBBBC9D6,0xACBCF940,0x32D86CE3,0x45DF5C75,0xDCD60DCF,0xABD13D59,0x26D930AC,\
          0x51DE003A,0xC8D75180,0xBFD06116,0x21B4F4B5,0x56B3C423,0xCFBA9599,0xB8BDA50F,\
          0x2802B89E,0x5F058808,0xC60CD9B2,0xB10BE924,0x2F6F7C87,0x58684C11,0xC1611DAB,\
          0xB6662D3D,0x76DC4190,0x1DB7106,0x98D220BC,0xEFD5102A,0x71B18589,0x6B6B51F,\
          0x9FBFE4A5,0xE8B8D433,0x7807C9A2,0xF00F934,0x9609A88E,0xE10E9818,0x7F6A0DBB,\
          0x86D3D2D,0x91646C97,0xE6635C01,0x6B6B51F4,0x1C6C6162,0x856530D8,0xF262004E,\
          0x6C0695ED,0x1B01A57B,0x8208F4C1,0xF50FC457,0x65B0D9C6,0x12B7E950,0x8BBEB8EA,\
          0xFCB9887C,0x62DD1DDF,0x15DA2D49,0x8CD37CF3,0xFBD44C65,0x4DB26158,0x3AB551CE,\
          0xA3BC0074,0xD4BB30E2,0x4ADFA541,0x3DD895D7,0xA4D1C46D,0xD3D6F4FB,0x4369E96A,\
          0x346ED9FC,0xAD678846,0xDA60B8D0,0x44042D73,0x33031DE5,0xAA0A4C5F,0xDD0D7CC9,\
          0x5005713C,0x270241AA,0xBE0B1010,0xC90C2086,0x5768B525,0x206F85B3,0xB966D409,\
          0xCE61E49F,0x5EDEF90E,0x29D9C998,0xB0D09822,0xC7D7A8B4,0x59B33D17,0x2EB40D81,\
          0xB7BD5C3B,0xC0BA6CAD,0xEDB88320,0x9ABFB3B6,0x3B6E20C,0x74B1D29A,0xEAD54739,\
          0x9DD277AF,0x4DB2615,0x73DC1683,0xE3630B12,0x94643B84,0xD6D6A3E,0x7A6A5AA8,\
          0xE40ECF0B,0x9309FF9D,0xA00AE27,0x7D079EB1,0xF00F9344,0x8708A3D2,0x1E01F268,\
          0x6906C2FE,0xF762575D,0x806567CB,0x196C3671,0x6E6B06E7,0xFED41B76,0x89D32BE0,\
          0x10DA7A5A,0x67DD4ACC,0xF9B9DF6F,0x8EBEEFF9,0x17B7BE43,0x60B08ED5,0xD6D6A3E8,\
          0xA1D1937E,0x38D8C2C4,0x4FDFF252,0xD1BB67F1,0xA6BC5767,0x3FB506DD,0x48B2364B,\
          0xD80D2BDA,0xAF0A1B4C,0x36034AF6,0x41047A60,0xDF60EFC3,0xA867DF55,0x316E8EEF,\
          0x4669BE79,0xCB61B38C,0xBC66831A,0x256FD2A0,0x5268E236,0xCC0C7795,0xBB0B4703,\
          0x220216B9,0x5505262F,0xC5BA3BBE,0xB2BD0B28,0x2BB45A92,0x5CB36A04,0xC2D7FFA7,\
          0xB5D0CF31,0x2CD99E8B,0x5BDEAE1D,0x9B64C2B0,0xEC63F226,0x756AA39C,0x26D930A,\
          0x9C0906A9,0xEB0E363F,0x72076785,0x5005713,0x95BF4A82,0xE2B87A14,0x7BB12BAE,\
          0xCB61B38,0x92D28E9B,0xE5D5BE0D,0x7CDCEFB7,0xBDBDF21,0x86D3D2D4,0xF1D4E242,\
          0x68DDB3F8,0x1FDA836E,0x81BE16CD,0xF6B9265B,0x6FB077E1,0x18B74777,0x88085AE6,\
          0xFF0F6A70,0x66063BCA,0x11010B5C,0x8F659EFF,0xF862AE69,0x616BFFD3,0x166CCF45,\
          0xA00AE278,0xD70DD2EE,0x4E048354,0x3903B3C2,0xA7672661,0xD06016F7,0x4969474D,\
          0x3E6E77DB,0xAED16A4A,0xD9D65ADC,0x40DF0B66,0x37D83BF0,0xA9BCAE53,0xDEBB9EC5,\
          0x47B2CF7F,0x30B5FFE9,0xBDBDF21C,0xCABAC28A,0x53B39330,0x24B4A3A6,0xBAD03605,\
          0xCDD70693,0x54DE5729,0x23D967BF,0xB3667A2E,0xC4614AB8,0x5D681B02,0x2A6F2B94,\
          0xB40BBE37,0xC30C8EA1,0x5A05DF1B,0x2D02EF8D

          dd 10
          Parámetro1 db 'Hola Mundo',0
.code
start:
      push Parámetro1
      call pCRC32
      ; A PARTIR DE ACÁ, EAX = 22436ed2h
      push 0
      call [ExitProcess]

; El parámetro a establecer debe contener la longitud de la cadena en sus primeros 4 bytes.

proc pCRC32 Texto:DWORD
     local CRC dd -1
     local i dd 0
     local Temp1 dd ?
     local Temp2 dd ?
     mov ecx,DWORD[Texto]
     mov ecx,DWORD[ecx-4]
     mov ebx,256 ; Inicializamos EBX con 256.
.Contar1:
     cmp DWORD[i],ecx
     je .Seguir1
     cmp DWORD[CRC],-1
     jne .SiNo1 ; Si no es menor a cero.
.Si1: ; Etiqueta de decoración.
     ; Temp1 = (((CRC And &7FFFFFFF) \ 256) Or &800000) And &FFFFFF
     mov eax,DWORD[CRC]
     and eax,0x7FFFFFFF
     xor edx,edx
     div ebx
     or eax,0x800000
     and eax,0xFFFFFF
     mov DWORD[Temp1],eax
     jmp .FinSi1
.SiNo1:
     ; Temp1 = (CRC \ 256) And &FFFFFF
     mov eax,DWORD[CRC]
     xor edx,edx
     div ebx
     and eax,0xFFFFFF
     mov DWORD[Temp1],eax
.FinSi1:
     ; CRC = Temp1 Xor (TLookup[(CRC Xor bArray[i]) And &FF])
     mov edi,DWORD[Texto]
     add edi,DWORD[i]
     mov eax,DWORD[CRC]
     xor al,BYTE[edi]
     movzx eax,al
     mov edi,4
     mul edi
     lea edi,[TLookup]
     add edi,eax
     mov eax,DWORD[Temp1]
     xor eax,DWORD[edi]
     mov DWORD[CRC],eax
     inc DWORD[i]
     jmp .Contar1
.Seguir1:
     mov eax,DWORD[CRC]
     xor eax,0xFFFFFFFF
     ret
endp

.end start