SCL Reference: if Statement
The SCL if statement provides decision based branching.
if booleanExpression then
scl statements
else // optional
scl statements
end if;
The boolean expression is what you would expect it to be. Here are a few examples:
//make RD1 echo the inverse of RD0
wait on RD0;
if RD0 == '1' then
RD1 <= '0';
else
RD1 <= '1';
end if;
//test pin voltage
if RD0 > 2500 mv then
RD1 <= '0';
RD2 <= '0';
end if;
//test boolean var
if testBool then
RD1 <= '0';
RD2 <= '0';
end if;