vb.net 补码计算

Private Function funcBM(ByVal strInput As Integer) As Integer

If strInput > 127 Then

Dim s() As Byte = {&H30, &H30, &H30, &H30, &H30, &H30, &H30, &H30}
Dim s1 As String
Dim i As Integer = 0
Dim val As Integer = 0
Dim sT(6) As Byte
s1 = Convert.ToString(strInput, 2)
s = System.Text.Encoding.ASCII.GetBytes(s1)

For i = 0 To 6
If s(i + 1) = &H31 Then
sT(i) = &H0
ElseIf s(i + 1) = &H30 Then
sT(i) = &H1
End If
Next

For i = 0 To 6
val = val + (sT(i) << (6 - i))
Next

funcBM = 0 - (val + 1)

Else

funcBM = strInput

End If

End Function