• Step1: 3 Multipliers + 1 Subtractor
• Step2: 2 Dividers + 1 Adder
• Step3: NIL (subtractor from Step1 can be used)
• Step4: NIL (subtractor from Step1 can be used)

3.  As Late As Possible Scheduling

As-Late-As-Possible (ALAP) scheduling is almost similar to ASAP, but instead of scheduling operations to early control steps, in ALSP, first the maximum number of control steps that are allowed is determined. Following that, the algorithm schedules each operation, one at a time, into the latest possible control step. In other words, ALAP algorithm schedules operations in the latest possible control step, subject to satisfying the (reverse) partial order, i.e., an operation is scheduled if and only if all its successors are scheduled in latter control steps. If ALAP algorithm can schedule all the operations within 1^st control step (as we move backward), scheduling is successful. It may be noted that like ASAP, ALAP algorithm also does not consider any resource constraints.

Algorithm for ALAP scheduling is given in Algorithm 2.

Algorithm 2: As Late As possible

Input: Operations O, Maximum number of control steps M.

Output: Control step for each operations, Status of scheduling .

Steps