Re: confused on Figure 1.6 implementation of Xor gate

Posted by cadet1620 on
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/confused-on-Figure-1-6-implementation-of-Xor-gate-tp3706181p3706921.html

I'm guessing that the multiple notations are throwing you off.  In normal arithmetic expressions we use '×', '·' and juxtaposition to mean multiplication, there are multiple notations for Boolean expressions.

Not can be '~', '!', '¬' or over-line.<br>
Or can be '+', '|', or upside down '^'.<br>
And can be '·', '^' or juxtaposition.
And has precedence over Or.  Not's precedence is often ambiguous; use ().

So all of these are the same:
_
ab+cd  =  (~a)&b|c&d  =  ((NOT a) AND b) OR (c AND d)

The overloading of '+' and juxtaposition for Boolean operations can be confusing since they look like normal arithmetic.

--Mark