A while  loop statement includes a sequence of statements that is to be executed repeatedly, zero or more times, depending on the condition mentioned in the header of the loop statement.

Syntax:

[ label: ] while condition loop
  sequential_statements
end loop [ label ]; 

Description:

The while loop statement is a sequential statement that contains a sequence of statements, which are supposed to as long as the condition is true.

The condition is evaluated before each execution of the sequence of statements. If the condition is false, the statements in the loop are not executed and the control is passed to the next statement after the end loop clause.

Example:

while I <= 8 loop 
  Output1(I) <= Input1(I+2) after 5 ns; 
  I := I + 1; 
end loop;

Note:

• The condition is tested at the start of the loop and once after each iteration, but not during the execution of the statements.

See also:

Exit, For loop, Loop, Next