Scoreboard basic idea
The scoreboard keeps a record of all data dependencies
- Keeps track of which registers are used as sources and destinations and which functional units use them
The scoreboard keeps a record of all pipe occupancies
- The original CDC 6600 was not pipelined but conceptually the scoreboard does not depend on pipelining
The scoreboard decides if an instruction can be issued
- Either the first time it sees it (no hazard) or, if not, at every cycle thereafter
The scoreboard decides if an instruction can store its result
- This is to prevent WAR hazards