'===========================================================================
' Subject: CALCULATE 32-BIT CRC IN PB/ASM    Date: 12-15-99 (17:47)       
' Author:  Randall L. Glass                  Code: PB                     
' Origin:  rlglass@yahoo.com               Packet: PB.ABC
'===========================================================================
'
'  -- CRC32.BAS --
'
'  Public Domain by Randall L Glass
'
'

$CPU 8086          'make compatible with XT systems
$LIB ALL OFF       'turn off all PowerBASIC libraries
$ERROR ALL OFF     'turn off all PowerBASIC error checking
$OPTIMIZE SIZE     'optimize for smaller code


DEFDWD A-Z

' calculates the 32 bit Crc using the byte method

CLS
LOCATE 5,1
SHARED CRC???
CRC??? = &H0FFFFFFFF
File$ = COMMAND$
PRINT "CRC is "
OPEN File$ FOR BINARY AS #1
Ln??? = LOF(1)
MTimer
DO
	IF Ln??? >= 32000 THEN
		GET$ #1,32000,Block$
		DECR Ln???,32000
		CrcVal??? = CRC32???(Block$)
	ELSE
		GET$ #1,Ln???,Block$
		CrcVal??? = CRC32???(Block$)
		EXIT LOOP
       	END IF
LOOP
CLOSE
Y! = MTIMER
PRINT Y!/1E+6;" Seconds CRC=";DHex$(NOT CrcVal???)
END



' compute updated CRC

FUNCTION Crc32???(Block$) PUBLIC
'CRC??? = Crc32Table(Crc??? XOR ByteVal?) XOR (SiftRight(Crc???,8) AND &H00FFFFFF)
  DIM CharByte AS DWORD,ByteVal AS BYTE
  Ln?? = LEN(Block$)
  CharByte??? = STRPTR32(Block$)
  'compute CRC
  ! MOV CX,Ln??
  ! MOV DX,CRC???[2]
  ! MOV AX,CRC???[0]
  ! LES DI,CharByte???
NEWCRC:
  ! MOV BL,ES:[DI]
  ! INC DI
  ! XOR BL,AL
  ! MOV AL,AH
  ! MOV AH,DL            ;CrcShifted??? = SHIFT RIGHT CRC???,8
  ! MOV DL,DH
  ! MOV DH,0
  ! MOV BH,0
  ! SHL BX,1
  ! SHL BX,1
  ! XOR AX,Crcdata??[BX]
  ! XOR DX,Crcdata??[BX+2]  ;Crc??? = Crc32Table???(Index?) XOR (Temp??? AND FACTOR???)
  ! LOOP NewCrc
  ! MOV CRC???[2],DX
  ! MOV CRC???[0],AX
Crc32??? = CRC???
END FUNCTION


FUNCTION DHex(HexDWord???) AS STRING
 DIM Lo AS WORD
 DIM Hi AS WORD
 ! les  bx, [bp+6]
 ! mov  ax, es:[bx+0]
 ! mov  Lo??, ax
 ! mov  ax, es:[bx+2]
 ! mov  Hi??, ax
 DHex = RIGHT$("000" + HEX$(Hi??), 4) + RIGHT$("000" + _
 HEX$(Lo??), 4)
END FUNCTION

CrcData:
! dw &H00
! dw &H00
! dw &H03096
! dw &H07707
! dw &H0612C
! dw &H0EE0E
! dw &H051BA
! dw &H09909
! dw &H0C419
! dw &H076D
! dw &H0F48F
! dw &H0706A
! dw &H0A535
! dw &H0E963
! dw &H095A3
! dw &H09E64
! dw &H08832
! dw &H0EDB
! dw &H0B8A4
! dw &H079DC
! dw &H0E91E
! dw &H0E0D5
! dw &H0D988
! dw &H097D2
! dw &H04C2B
! dw &H09B6
! dw &H07CBD
! dw &H07EB1
! dw &H02D07
! dw &H0E7B8
! dw &H01D91
! dw &H090BF
! dw &H01064
! dw &H01DB7
! dw &H020F2
! dw &H06AB0
! dw &H07148
! dw &H0F3B9
! dw &H041DE
! dw &H084BE
! dw &H0D47D
! dw &H01ADA
! dw &H0E4EB
! dw &H06DDD
! dw &H0B551
! dw &H0F4D4
! dw &H085C7
! dw &H083D3
! dw &H09856
! dw &H0136C
! dw &H0A8C0
! dw &H0646B
! dw &H0F97A
! dw &H0FD62
! dw &H0C9EC
! dw &H08A65
! dw &H05C4F
! dw &H01401
! dw &H06CD9
! dw &H06306
! dw &H03D63
! dw &H0FA0F
! dw &H0DF5
! dw &H08D08
! dw &H020C8
! dw &H03B6E
! dw &H0105E
! dw &H04C69
! dw &H041E4
! dw &H0D560
! dw &H07172
! dw &H0A267
! dw &H0E4D1
! dw &H03C03
! dw &H0D447
! dw &H04B04
! dw &H085FD
! dw &H0D20D
! dw &H0B56B
! dw &H0A50A
! dw &H0A8FA
! dw &H035B5
! dw &H0986C
! dw &H042B2
! dw &H0C9D6
! dw &H0DBBB
! dw &H0F940
! dw &H0ACBC
! dw &H06CE3
! dw &H032D8
! dw &H05C75
! dw &H045DF
! dw &H0DCF
! dw &H0DCD6
! dw &H03D59
! dw &H0ABD1
! dw &H030AC
! dw &H026D9
! dw &H03A
! dw &H051DE
! dw &H05180
! dw &H0C8D7
! dw &H06116
! dw &H0BFD0
! dw &H0F4B5
! dw &H021B4
! dw &H0C423
! dw &H056B3
! dw &H09599
! dw &H0CFBA
! dw &H0A50F
! dw &H0B8BD
! dw &H0B89E
! dw &H02802
! dw &H08808
! dw &H05F05
! dw &H0D9B2
! dw &H0C60C
! dw &H0E924
! dw &H0B10B
! dw &H07C87
! dw &H02F6F
! dw &H04C11
! dw &H05868
! dw &H01DAB
! dw &H0C161
! dw &H02D3D
! dw &H0B666
! dw &H04190
! dw &H076DC
! dw &H07106
! dw &H01DB
! dw &H020BC
! dw &H098D2
! dw &H0102A
! dw &H0EFD5
! dw &H08589
! dw &H071B1
! dw &H0B51F
! dw &H06B6
! dw &H0E4A5
! dw &H09FBF
! dw &H0D433
! dw &H0E8B8
! dw &H0C9A2
! dw &H07807
! dw &H0F934
! dw &H0F00
! dw &H0A88E
! dw &H09609
! dw &H09818
! dw &H0E10E
! dw &H0DBB
! dw &H07F6A
! dw &H03D2D
! dw &H086D
! dw &H06C97
! dw &H09164
! dw &H05C01
! dw &H0E663
! dw &H051F4
! dw &H06B6B
! dw &H06162
! dw &H01C6C
! dw &H030D8
! dw &H08565
! dw &H04E
! dw &H0F262
! dw &H095ED
! dw &H06C06
! dw &H0A57B
! dw &H01B01
! dw &H0F4C1
! dw &H08208
! dw &H0C457
! dw &H0F50F
! dw &H0D9C6
! dw &H065B0
! dw &H0E950
! dw &H012B7
! dw &H0B8EA
! dw &H08BBE
! dw &H0887C
! dw &H0FCB9
! dw &H01DDF
! dw &H062DD
! dw &H02D49
! dw &H015DA
! dw &H07CF3
! dw &H08CD3
! dw &H04C65
! dw &H0FBD4
! dw &H06158
! dw &H04DB2
! dw &H051CE
! dw &H03AB5
! dw &H074
! dw &H0A3BC
! dw &H030E2
! dw &H0D4BB
! dw &H0A541
! dw &H04ADF
! dw &H095D7
! dw &H03DD8
! dw &H0C46D
! dw &H0A4D1
! dw &H0F4FB
! dw &H0D3D6
! dw &H0E96A
! dw &H04369
! dw &H0D9FC
! dw &H0346E
! dw &H08846
! dw &H0AD67
! dw &H0B8D0
! dw &H0DA60
! dw &H02D73
! dw &H04404
! dw &H01DE5
! dw &H03303
! dw &H04C5F
! dw &H0AA0A
! dw &H07CC9
! dw &H0DD0D
! dw &H0713C
! dw &H05005
! dw &H041AA
! dw &H02702
! dw &H01010
! dw &H0BE0B
! dw &H02086
! dw &H0C90C
! dw &H0B525
! dw &H05768
! dw &H085B3
! dw &H0206F
! dw &H0D409
! dw &H0B966
! dw &H0E49F
! dw &H0CE61
! dw &H0F90E
! dw &H05EDE
! dw &H0C998
! dw &H029D9
! dw &H09822
! dw &H0B0D0
! dw &H0A8B4
! dw &H0C7D7
! dw &H03D17
! dw &H059B3
! dw &H0D81
! dw &H02EB4
! dw &H05C3B
! dw &H0B7BD
! dw &H06CAD
! dw &H0C0BA
! dw &H08320
! dw &H0EDB8
! dw &H0B3B6
! dw &H09ABF
! dw &H0E20C
! dw &H03B6
! dw &H0D29A
! dw &H074B1
! dw &H04739
! dw &H0EAD5
! dw &H077AF
! dw &H09DD2
! dw &H02615
! dw &H04DB
! dw &H01683
! dw &H073DC
! dw &H0B12
! dw &H0E363
! dw &H03B84
! dw &H09464
! dw &H06A3E
! dw &H0D6D
! dw &H05AA8
! dw &H07A6A
! dw &H0CF0B
! dw &H0E40E
! dw &H0FF9D
! dw &H09309
! dw &H0AE27
! dw &H0A00
! dw &H09EB1
! dw &H07D07
! dw &H09344
! dw &H0F00F
! dw &H0A3D2
! dw &H08708
! dw &H0F268
! dw &H01E01
! dw &H0C2FE
! dw &H06906
! dw &H0575D
! dw &H0F762
! dw &H067CB
! dw &H08065
! dw &H03671
! dw &H0196C
! dw &H06E7
! dw &H06E6B
! dw &H01B76
! dw &H0FED4
! dw &H02BE0
! dw &H089D3
! dw &H07A5A
! dw &H010DA
! dw &H04ACC
! dw &H067DD
! dw &H0DF6F
! dw &H0F9B9
! dw &H0EFF9
! dw &H08EBE
! dw &H0BE43
! dw &H017B7
! dw &H08ED5
! dw &H060B0
! dw &H0A3E8
! dw &H0D6D6
! dw &H0937E
! dw &H0A1D1
! dw &H0C2C4
! dw &H038D8
! dw &H0F252
! dw &H04FDF
! dw &H067F1
! dw &H0D1BB
! dw &H05767
! dw &H0A6BC
! dw &H06DD
! dw &H03FB5
! dw &H0364B
! dw &H048B2
! dw &H02BDA
! dw &H0D80D
! dw &H01B4C
! dw &H0AF0A
! dw &H04AF6
! dw &H03603
! dw &H07A60
! dw &H04104
! dw &H0EFC3
! dw &H0DF60
! dw &H0DF55
! dw &H0A867
! dw &H08EEF
! dw &H0316E
! dw &H0BE79
! dw &H04669
! dw &H0B38C
! dw &H0CB61
! dw &H0831A
! dw &H0BC66
! dw &H0D2A0
! dw &H0256F
! dw &H0E236
! dw &H05268
! dw &H07795
! dw &H0CC0C
! dw &H04703
! dw &H0BB0B
! dw &H016B9
! dw &H02202
! dw &H0262F
! dw &H05505
! dw &H03BBE
! dw &H0C5BA
! dw &H0B28
! dw &H0B2BD
! dw &H05A92
! dw &H02BB4
! dw &H06A04
! dw &H05CB3
! dw &H0FFA7
! dw &H0C2D7
! dw &H0CF31
! dw &H0B5D0
! dw &H09E8B
! dw &H02CD9
! dw &H0AE1D
! dw &H05BDE
! dw &H0C2B0
! dw &H09B64
! dw &H0F226
! dw &H0EC63
! dw &H0A39C
! dw &H0756A
! dw &H0930A
! dw &H026D
! dw &H06A9
! dw &H09C09
! dw &H0363F
! dw &H0EB0E
! dw &H06785
! dw &H07207
! dw &H05713
! dw &H0500
! dw &H04A82
! dw &H095BF
! dw &H07A14
! dw &H0E2B8
! dw &H02BAE
! dw &H07BB1
! dw &H01B38
! dw &H0CB6
! dw &H08E9B
! dw &H092D2
! dw &H0BE0D
! dw &H0E5D5
! dw &H0EFB7
! dw &H07CDC
! dw &H0DF21
! dw &H0BDB
! dw &H0D2D4
! dw &H086D3
! dw &H0E242
! dw &H0F1D4
! dw &H0B3F8
! dw &H068DD
! dw &H0836E
! dw &H01FDA
! dw &H016CD
! dw &H081BE
! dw &H0265B
! dw &H0F6B9
! dw &H077E1
! dw &H06FB0
! dw &H04777
! dw &H018B7
! dw &H05AE6
! dw &H08808
! dw &H06A70
! dw &H0FF0F
! dw &H03BCA
! dw &H06606
! dw &H0B5C
! dw &H01101
! dw &H09EFF
! dw &H08F65
! dw &H0AE69
! dw &H0F862
! dw &H0FFD3
! dw &H0616B
! dw &H0CF45
! dw &H0166C
! dw &H0E278
! dw &H0A00A
! dw &H0D2EE
! dw &H0D70D
! dw &H08354
! dw &H04E04
! dw &H0B3C2
! dw &H03903
! dw &H02661
! dw &H0A767
! dw &H016F7
! dw &H0D060
! dw &H0474D
! dw &H04969
! dw &H077DB
! dw &H03E6E
! dw &H06A4A
! dw &H0AED1
! dw &H05ADC
! dw &H0D9D6
! dw &H0B66
! dw &H040DF
! dw &H03BF0
! dw &H037D8
! dw &H0AE53
! dw &H0A9BC
! dw &H09EC5
! dw &H0DEBB
! dw &H0CF7F
! dw &H047B2
! dw &H0FFE9
! dw &H030B5
! dw &H0F21C
! dw &H0BDBD
! dw &H0C28A
! dw &H0CABA
! dw &H09330
! dw &H053B3
! dw &H0A3A6
! dw &H024B4
! dw &H03605
! dw &H0BAD0
! dw &H0693
! dw &H0CDD7
! dw &H05729
! dw &H054DE
! dw &H067BF
! dw &H023D9
! dw &H07A2E
! dw &H0B366
! dw &H04AB8
! dw &H0C461
! dw &H01B02
! dw &H05D68
! dw &H02B94
! dw &H02A6F
! dw &H0BE37
! dw &H0B40B
! dw &H08EA1
! dw &H0C30C
! dw &H0DF1B
! dw &H05A05
! dw &H0EF8D
! dw &H02D02