Boolean functions accepts numeric values..

[Rashme_SR]

I recently came to know that all Boolean functions accept numeric values as well. But what is the purpose of it?

I found the Boolean functions outputting some random values while inputting numeric values..

Thank you!!

Best Regards,

Rashme SR

[Yamaeda]

The definition of a bool is x != 0, so that's what the function should equate to.

/Y

[GerdW]

Hi Rashme,

But what is the purpose of it?

The purpose is to apply boolean functions to integer values.

Instead of scalar booleans you can put 8/16/32/64 bits in an integer value and you can apply a boolean function to the whole integer (and all it's bits) at once.

Quite handy once you learn such stuff (when programming µCs at the assembler level)!

[Yamaeda]

Ah, i misunderstood. Gerd is spot on. If, e.g. you want to know if the 4th bit is set, you can AND with 8 and compare to 0. If 0 it wasn't set, else it was. Now how is that beneficial? Many protocols just bits as flags, e.g. Intermec uses a 32 bit integer to set all relays in a module and thus you need to filter and set bits with AND and OR to do it efficiently.

/Y

[Yamaeda]

Another common use case is x AND 1 to see if a number is even/odd.

/Y

[Rashme_SR]

I dont understand clearly. Can you please attach an example?

[crossrulz · Accepted solution]

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@Rashme_SR wrote:

I dont understand clearly. Can you please attach an example?

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What do you not understand?

When boolean logic is used on integers, the logic is done on a per bit basis.  I do this all the time for encoding and decoding data from specific protocols (some more wild than others).  This is also needed for many data checks (like a CRC or Reed Solomon) and for encryption (AES, DES, 3DES).

[Rashme_SR]

Thank you so much.. finally i understood.. Doing binary calculations using numeric controls.. Its awesome

Regards,

Rashme SR