while loop

Loops are used to perform the same set of statements multiple times. The while loop runs the statement until a condition is no longer met. 

while condition
   blockWhile
end
condition is an expression that is evaluated each time the loop is run. If condition evaluates to a nonzero value, the statements in blockWhile are run and the process is repeated. If condition evaluates to a zero value (false), the statements in blockWhile are skipped.The number of times the loop is executed depends on condition and blockWhile. If condition is initially false, the loop is never executed.
while a>1           
      a=a/2
end