Central Reservation Station (CRS) cont.
Low Clock Phase
- Update all shelves with values from result bus (output of execution units)
- Entries which are updated can be dispatched this clock
- In reality, this update is being done throughout the high phase and into the low phase, but due to modeling constraints, will do it in low phase only.
- Dispatch ready instructions to execution units
- Examine all shelves for operands with both valid bits set
- Dispatching the instructions frees the shelf entry (mark it as invalid)
- Always dispatch EUMAX instructions - dispatch a NOP if can’t fine a shelf entry that is valid.