Functions, Operators, Switch Cases and Truth Tables : Combinational Assignments

Combinational Assignments

A combinational assignment has the following syntax:

CE =EXP1 when COND1 else
EXP2 when COND2 else
. . .
EXPN
 
 

In this syntax:

CE (the combinational element) - A primitive data-item or condition, or an alias data-item
EXP1 - A data-item or condition expression
COND1 - A condition expression
N - A number greater than or equal to 1. If N=1, the assignment is simply

CE = EXPl

Combinational assignments in a sequence are separated by semi-colons, like actions in a sequence.

For example:

DI_CE=DI_expression
DI_CE=DI-expression_1 when CO_expression
else DI_expression_2
DI_CE=DI_expression when CO_expression_1
else DI_expression_2 when CO_expression_2
else DI_expression_3
 
CO_CE=CO_expression
CO_CE=CO_expression_1 when CO_expression
else DI_expression_2
CO_CE=CO_expression when CO_expression_1
else CO_expression_2 when CO_expression_2
else CO_expression_3