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Swordfish help please

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Mark_R

Member
Hi,

I have a project which I was planning on using a CUBLOC 280CS but am considering switching to a PIC using Swordfish.

I struggled with some CRC calculation code which will be needed for my hardware. I have it working correctly on the CUBLOC hardware. I have tried converting it to swordfish and it comples OK but I have no idea if its syntax is correct, in fact I seriously doubt it is based upon the "hints" the compiler is giving me.

Could someone take a look and see if I'm even close? I don't have the hardware yet, not convinced I'm going with the PIC yet.

Working CUBLOC code (I don't know if it's in good form, but it works, be gentle):
Code:
' CRC-16 Calculation

Const Device = CB220
Ramclear
Wait 200

Dim CRC As Integer
Dim InByte(9) As Byte
Dim OutByte(2) As Byte
Dim message(100) As Integer
Dim MessageCount As Integer

Dim j As Integer
Dim i As Integer

Dim LowB As Byte
Dim HighB As Byte
Dim ShiftBit As Byte
Dim FINALCRC As Integer

'Test bytes for testing
'This will be the data passed to the function

InByte(0) = 0xAA 'test input AA
InByte(1) = 0x05 'test input "05"
InByte(2) = 0x05 'test input "05"
InByte(3) = 0x00
InByte(4) = 0x00
InByte(5) = 0x00
InByte(6) = 0x00
InByte(7) = 0x00
InByte(8) = 0x00

MessageCount = 2 'needs to be lengh of string to be CRCd
CRC = 0xffff  'CRC seed per specification

For j = 0 To MessageCount
	CRC = CRC Xor InByte(j)

	For i = 1 To 8
		ShiftBit = (CRC And 1)
		CRC = ((CRC And 0xfffe)/2 )
		If CRC <0 Then CRC = CRC + 0x8000 '32768 Dec.
		If ShiftBit = 1 Then CRC = CRC Xor 0x8408
	
	Next
	
Next

CRC = Not CRC

HighB = (CRC And 0xff) ' Mask hi bits
LowB = ((CRC And 0xff00) /0x100) '256 Dec. - Mask low bits

If HighB < 0 Then HighB = (HighB + 0x8000)
HighB = (HighB And 0xff)

FINALCRC.Byte0 = LowB 'swap low and high bytes
FINALCRC.Byte1 = HighB

'********************************************
'********************************************
' This section for testing
' not part of final function
' sample data and known correct results:
' an input of "AA 05 05" should result in a CRC of "74 93"
' an Input of "AA 05 01" should result In a CRC of "50 D5"

Dim MessageLength As Integer
Dim z As Integer

MessageLength = MessageCount + 1

Debug "Input =" 
For z = 0 To MessageCount
	Debug Hex InByte(z)," "
Next

Debug Cr, "Message Length = ", Hex MessageLength, Cr
Debug "FINALCRC = ", Hex FINALCRC, Cr 'output

'*********************************************
'*********************************************

Swordfish so far
Code:
Dim CRC As Integer
Dim InByte(9) As Byte
Dim OutByte(2) As Byte
Dim message(100) As Integer
Dim MessageCount As Integer

Dim j As Integer
Dim i As Integer

Dim LowB As Byte
Dim HighB As Byte
Dim ShiftBit As Byte
Dim FINALCRC As Integer

'Test bytes for testing
'This will be the data passed to the function

InByte(0) = $AA 'test input AA
InByte(1) = $05 'test input "05"
InByte(2) = $05 'test input "05"
InByte(3) = $00
InByte(4) = $00
InByte(5) = $00
InByte(6) = $00
InByte(7) = $00
InByte(8) = $00

end

MessageCount = 2 'needs to be lengh of string to be CRCd
CRC = $ffff  'CRC seed per specification

For j = 0 To MessageCount
	CRC = CRC Xor InByte(j)

	For i = 1 To 8
		ShiftBit = (CRC And 1)
		CRC = ((CRC And $fffe)/2 )
		If CRC <0 Then CRC = CRC + $8000 '32768 Dec.
		If ShiftBit = 1 Then CRC = CRC Xor $8408
	
	Next
	
Next

CRC = Not CRC

HighB = (CRC And $ff) ' Mask hi bits
LowB = ((CRC And $ff00) /$100) '256 Dec. - Mask low bits

If HighB < 0 Then HighB = (HighB + $8000)
HighB = (HighB And $ff)

FINALCRC.Byte0 = LowB 'swap low and high bytes
FINALCRC.Byte1 = HighB

Thanks.
 
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