how to use compare function

[zhiyuan16]

dear all how to use compare function, the following is the example code for reading input bit

Dim iShift As Double, I As Double

iShift = 1
For I = 0 To 7
    Compare = Int(InputByte And iShift)
    If Compare = iShift Then   'Bit Turn OFF
        AMD\_GalilInputAxisBit(I) = 1
        AMD\_GalilInputBit(I) = 1
        'DigitalIO.Label2(I).BackColor = vbRed
    Else
        AMD\_GalilInputAxisBit(I) = 0 'Bit Turn ON
        AMD\_GalilInputBit(I) = 0
        'DigitalIO.Label2(I).BackColor = vbGreen
    End If
    iShift = iShift \* 2
Next I

[Dave Kreskowiak]

What are you talking about? You're not using a Compare method or function at all in this code. All you're doing is comparing a numeric value to another one.

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Dave Kreskowiak

[Luc Pattyn]

Hi, seems acceptable; here are a few remarks: 1. when manipulating bits, make sure your variables are integers, so don't use double. 2. while your comparison to iShift is OK, you could as well test for zero. 3. maybe, just maybe, you have your two cases (equal and not equal) swapped. This would be my style (assuming InputByte is an integer too):

Dim I As Integer
Dim iShift As Integer = 1
For I = 0 To 7
    If (InputByte And iShift)= 0 Then   'Bit Turn OFF
        AMD\_GalilInputAxisBit(I) = 0
        AMD\_GalilInputBit(I) = 0
    Else 'Bit Turn ON
        AMD\_GalilInputAxisBit(I) = 1 
        AMD\_GalilInputBit(I) = 1
    End If
    iShift = iShift + iShift
Next I

:)

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