On an ALU data sheet there are logic formulae showing the results that will be output for various inputs.


(Second from last row on page 3.)

I assume that A+B means bitwise A OR B, this would follow, as the plus in a circle is XOR.

Does AB mean bitwise A AND B?

  • \$\begingroup\$ It would follow, because the arithmetic plus is indicated by PLUS. And since the multiplication is not among the parts capability (as indicated on the first page), AB would mean bitwise A AND B. \$\endgroup\$ – Eugene Sh. Jun 23 '16 at 15:48
  • \$\begingroup\$ A lot of sources are already on the google search, no offense I don't think there is a question here. \$\endgroup\$ – MaMba Jun 23 '16 at 16:16
  • \$\begingroup\$ Unless it is a regex expression your deduction is true. \$\endgroup\$ – Sparky256 Jun 23 '16 at 22:29

Yes, when written as multiplication in normal math, it means AND in Boolean logic. This does make some sense when you think about it. Make a truth table of multiplying two value that can be either 0 or 1. The result is 0 except when both are 1, then the result is 1. That's exactly what AND does.

This logic doesn't really follow for "+", unless you consider 0 FALSE and anything else TRUE.

  • \$\begingroup\$ So many words instead just yes \$\endgroup\$ – Gregory Kornblum Jun 23 '16 at 16:31
  • 5
    \$\begingroup\$ A one word answer is pretty much considered useless, and quickly downvoted. Points for the explanation. \$\endgroup\$ – R Drast Jun 23 '16 at 16:46
  • 2
    \$\begingroup\$ unless you consider 0 FALSE and anything else TRUE Like most C-derived programming languages, for example :) \$\endgroup\$ – cat Jun 23 '16 at 18:25

You are right AB mean A AND B . It is faster to write AB than A dot B or A AND B

  • 5
    \$\begingroup\$ Is it also faster to write "right" than it is to write "write" right? \$\endgroup\$ – Ben Voigt Jun 23 '16 at 15:51
  • \$\begingroup\$ @BenVoigt Didn't realize the edit, filled the comment box with alternating "right" and "write" to measure typing speed. Only then I noticed the earlier revision. \$\endgroup\$ – Kroltan Jun 24 '16 at 2:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.