CISC vs RISC Architectures

A technique to address the issue of local changes with each procedure call and return. It involves creating new sets of registers (register windows) for each procedure call, with each window overlapping with the previous one. This overlapping allows efficient parameter passing between procedures without needing to save and restore values in memory.

A computer architecture featuring a large and complex set of instructions. Designed to support high-level languages (HLLs) and improve performance.

A type of computer architecture with a small set of simple instructions, optimized for efficiency and speed. It favors register-to-register operations, simple addressing modes, and streamlined instruction formats.

A fast, small memory component used to store frequently accessed data and instructions. It acts as a buffer between the main memory and the processor.

A high-speed memory component used to store frequently accessed variables. Similar to a cache, but much faster.

RISC researchers argue that CISC's complex instructions don't simplify compilers, as the compiler still needs to find specific cases that match the instruction. This complexity often outweighs the benefits of fewer lines of code.

The expectation that CISC would lead to smaller and faster programs due to the more efficient execution of complex instructions. However, this isn't always true due to the complexity of decoding and executing these instructions, often resulting in larger program sizes.

Evidence supporting the advantages of RISC architectures. This includes factors like speed, efficiency, and cost-effectiveness.

CISC processors use a complex set of instructions, each potentially carrying out a complex operation. RISC processors, in contrast, use a limited set of simpler instructions.

High-level languages (HLLs) provided a way for programmers to express complex ideas concisely, without needing to understand the intricate details of machine code. This made programming more accessible and efficient.

The "semantic gap" is the mismatch between what high-level languages can express and what computer processors can directly execute. This gap existed because early processors had simple instruction sets.

To bridge the semantic gap, processors were designed with more complex instructions that closely resembled the instructions used in high-level languages.

Studies showed that programs written in high-level languages benefited from a large number of processor registers available for data storage. These registers allow faster data access and improve program efficiency.

One approach to implementing a large register file is to provide more registers in the hardware design of the processor. This directly increases the storage capacity for data.

Optimizing the instruction pipeline involves streamlining the execution of instructions within the processor. This can include techniques like pipelining, where instructions are broken down into smaller steps and processed concurrently.

Another approach is to optimize the compiler's ability to effectively utilize the limited number of registers available. This involves careful allocation of registers and maximizing their use.