Converting numeric array into boolean (bits)

[Sarah_UCL]

Hello all,

I would be grateful for some advice regarding this problem.

I have a large array of 16bit unsigned data.  The data is composed from two different sources so I need to be able to retrieve the 16bits as two arrays of 8 bits for each position in the array.  For example, if the array were 100x100, the original data stream would have been 20000 bits long, I would have had 100x100 array of 8-bit unsigned integers followed by another 100x100 array of 8 bit unsigned integers.  When I read it into Labview, I need to read it as 16-bit in order to retrieve all of the data from the file.  What I need to do is read in this data and for each position in the array, separate the 16-bit values into the two 8-bit values then re-join so the first 8-bit value attaches to the 10,000th 8-bit value to make a new 16-bit value composed from the two different data sources.  I have tried indexing the array and converting each number to boolean but this takes far too long to be viable.  Is there a better way to do this?  Please ask if you need more explanation.

Thanks in advance,

Sarah

[tst]

I can't say that I really understand how you're getting the data, or which 2 bytes you're joining at each stage, but I would suggest you start by looking in the Advanced>>Data Manipulation palette (specifically Split Number and Join Numbers, which can operate on arrays as well).

If this doesn't help, I suggest you post your code with some example data, so that we can understand better.

[Sarah_UCL]

Thanks for your response, the functions in that palette have helped greatly.  I now have one further question.  If I have an 8-bit integer but only want to use 4-bits (in this case, 4-bits contain debug data, 4-bits contain the output data), is there a function I can use?  I have used the split number function to break the original 16-bit integer down into 8-bit but this function does not take 8-bit data as an input so I cannot repeat the process.

Thanks again,

Sarah

[GerdW]

Hi Sarah,

you can use the AND primitive to mask the needed 4 bits.
If you need the upper 4 bits of an U8 you can use a divide by 16.

Oh, that reminds me of that good old Quotient&Remainder: just divide by 16. The remainder gives you the lower 4 bits, the quotient represents the upper 4 bits.

[Sarah_UCL]

Forgive my ignorance but the AND function requires boolean inputs.  From my U8 number, how would I use this function?

Thanks for the advice.

Sarah

[jasonhill]

If you look at the help for AND, you will see that it accepts numbers as well as booleans.  This applies to most of the logical operators; NOT, OR, XOR, etc.

[Sarah_UCL]

Thanks very much, that works perfectly.

Sarah