Replace instructions and and xor by nand or nor

[jan-ferdinand]

The current set of binary instructions available in Triton VM, and and xor, is functionally complete, but not minimally so. Replacing them by either nand or nor

• does not change completeness,
• marginally decreases usability (or and not are not natively available anyway),
• simplifies the instruction set architecture, and
• simplifies the U32 Table.

(Originally issue number 41 in the internal issue tracker.)

[jan-ferdinand]

This is pretty tightly coupled with #8. Furthermore, we need a benchmark target before the question can be answered – the investigation is blocked by #7.

[jan-ferdinand]

(Originally posted by @aszepieniec.)

Also worth noting, for u32s:

A + B == (A ^ B) + ((A & B) << 1)

and so

A ^ B == A + B - ((A & B) << 1)

Please verify. Credit goes to @bobbinth who, IIRC, credited Daniel Lubarov.