Question

Explain the use of large register file for risc machines with the help of an example.

Answer 1

Answer:

Use of large Register file in RISC

The register storage is the faster storage device, faster than even the main memory and the cache. Thus, a strategy is needed that will allow the most frequently accessed operands to be kept in registers and to minimize register memory operations.

Answer 2

Reduced Instruction Set Architecture (RISC) :

The main idea is to simplify hardware by using an instruction set composed of a few basic steps for loading, evaluating, and storing operations. A store command stores data in the same way that a load command does.

RISC Characteristics -

1. Simpler instructions require simpler decoding.
2. Instruction comes undersize of one word.
3. A single clock cycle is required to execute an instruction.
4. Registers that are more general-purpose.
5. Modes of Simple Addressing
6. There are fewer data types.
7. A pipeline is feasible.

The use of larger register file in RISC machines is such that A large number of registers can be used to store intermediate results and optimize operand references. The advantage of register storage over memory storage is that registers can transfer information to and from other registers much faster than memory can.

Example:

For a RISC machine cycle time is 75ns

Then, ($10^{6}$*0.80*1 + $10^{6}*0.20*14$)*0.75*$10^{-7}$ = 0.27s

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