This is the loop Repeat/Until:
the instructions between REPEAT and UNTIL are repeated until the condition specified is False, i.e. the exit is when the condition is verified; the conditions are specified in UNTIL statement in the same manner as IF instruction.This loop is executed at least one time.
UNTIL (var1,comp1,var2),op,(var3,comp2,var4)...
Terminate the Repeat control block: conditions are evaluated: if False control retun to REPEAT statement and block is newly executed otherwise control pass to statement next to UNTIL. In a program (or subroutine) every Repeat must be closed by an UNTIL.
The conditions are specified in UNTIL statement in the same manner as IF instruction