Q.Write a pseudocode for creating a scoreboard for a hockey match.

The Scoreboard Algorithm: Intuition First

Imagine you're watching a cricket match. The scoreboard shows runs, wickets, overs, and individual player scores. You don't need to replay the entire match to know who's winning — the scoreboard gives you a snapshot of the state of the game at any moment.

Now imagine you're a computer processor trying to execute multiple instructions at once. Some instructions depend on the results of others. If instruction B needs the result of instruction A, you can't run B until A finishes. But you also don't want to just sit idle — you want to keep working on other independent instructions while waiting.

The Scoreboard Algorithm is a hardware technique that lets a processor do exactly that: keep track of which instructions are using which resources, and dynamically decide when to start new instructions, all while maintaining correctness.

The Core Problem

A processor has multiple functional units (adders, multipliers, memory ports, etc.). Instructions arrive in order, but we want to execute them out of order to keep the units busy. The challenge: an instruction that reads a register must wait until the instruction that writes that register has finished. Otherwise, you get the wrong answer.

The Scoreboard solves three questions for every instruction:

1. Are the resources free? (Is the functional unit available?)
2. Are the operands ready? (Have the source registers been computed?)
3. Will the result overwrite something still needed? (Is the destination register safe to write?)

The Precise Statement

The Scoreboard Algorithm maintains three tables in hardware:

1. Instruction Status

Records which of the four stages each instruction has passed through:

2. Functional Unit Status

For each functional unit, tracks:

• Busy: Is the unit currently in use?
• Op: What operation is it performing?
• Fi: Destination register
• Fj, Fk: Source registers
• Qj, Qk: Which functional unit will produce each source operand (if not yet ready)
• Rj, Rk: Are the source operands ready? (Yes/No)

3. Register Result Status

For each register, indicates which functional unit (if any) will write its result. If a register has no pending write, it's marked as available.

How It Works: Step by Step

Issue: If the functional unit is free and no hazards exist, the instruction is issued. The scoreboard records which registers it reads and which it will write.

Read Operands: The instruction waits until both source registers are ready (no pending writes from earlier instructions). Once ready, it reads them and proceeds.

Execute: The functional unit performs the operation. This takes as many cycles as needed.

Write Result: The instruction waits until no earlier instruction that reads the destination register is still waiting. This prevents Write-After-Read (WAR) hazards — you don't want to overwrite a value that a still-pending instruction needs to read. …