Xor_Factors Keyword

Syntax:

XOR_FACTORS
signal name = xor_factors ;

Use

The XOR_Factor section allows you to specify a Boolean expression that is to be factored out of (and XORed with) the sum-of-products reduced equations. This can result in dramatic reductions in the size of the reduced equations. The XOR_Factor feature is a technique for converting a sum of products (SOP) equation into an exclusive OR (XOR) equation. The resulting equation contains the sum of product functions that, when exclusive ORed together, have the same function as the original. The XOR_Factor equation will be divided into the original equation, with factor (or its complement) on one side of the XOR and the remainder on the other side.

Example

For the following equations,

!Q16 = A & B & !D
# A & B & !C
# !B & C & D
# !A & C & D

a useful XOR_Factor would be

XOR_Factors

Q16 = A & B;