The Begin and End Statements

There are cases where a group of wordlines must all specify the same condition and the same set of commands. The "begin" and "end" statements allow conditions and commands to be specified for sets of wordlines without repetitive coding. To illustrate consider the following example.

a=1: begin ADD->next_state
b=2: word 1->sub
c=0: word 2->sub
d=3: word SUBT->next_state,0->sub
end

Without the "begin" and "end" statements this example would be written as follows.

a=1&b=2: word ADD->next_state,1->sub
a=1&c=0: word ADD->next_state,2->sub
a=1&d=3: word SUBT->next_state,0->sub

The condition on a "begin" statement is ANDed with the conditions on the "word" statements contained between the "begin" and "end" statements. Conditions on the "word" statements may not override conditions on the "begin" statement. Commands on the "begin" statement are combined with commands on the "word" statement. The commands on the "word" statement may override the commands on the "begin" statement. "Begin" statements may be nested arbitrarily.