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Boolean expressions are sets of nodes, numbers, constants, and other Boolean expressions, separated by operators and/or comparators, and optionally grouped with parentheses. A Boolean equation sets a node or group equal to the value of a Boolean expression.
The boole1.tdf file shown below shows two simple Boolean expressions that represent two logic gates.
SUBDESIGN boole1 ( a0, a1, b : INPUT; out1, out2 : OUTPUT; ) BEGIN out1 = a1 & !a0; out2 = out1 # b; END;
In this sample file, the out1
output is driven by the logical AND
of a1
and the inverse of a0
, and the out2
output is driven by the logical OR
of out1
and b
. Since these equations are evaluated concurrently, their order in the file is not important.
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