Re-fetching Operands of Rejected Instructions
If the CRS has rejected 1 or more issued instructions (rejected because of unavailability of free shelves), the DRR has to replace the accepted instructions with NOPs and refetch the operands of the rejected instructions.
The operands re-fetching must be done DIFFERENTLY from the original operand fetch.
a. drr must read the current operand status of the issued instructions from the issue bus (in the VHDL model of the drr, the issue bus is of type inout, which allows reads as well as writes).
b. If the operand status is TRUE, then correct value has already been fetched.