What are the characteristics of a RISC machine? Also explain the pipelining concept in a RISC machine?

Q:- What are the characteristics of a RISC machine? Also, explain the pipelining concept in a RISC machine?

answer:- 

              RISC / CISC Characteristics (PowerPC) RISC Technology References: Chakravarty and Cannon, Chapter 2 Kacmarcik, Optimizing PowerPC Code Modern programmers use assembly:. for hand coding for speed for debugging Common features of CISC: many instructions that access memory directly. RISC (developed in the 1970s) was to create a machine (with a very fast clock cycle) that instructed one instruction/machine cycle of the rate at the process. Pipelining was
required to achieve this instruction rate. Typical current RISC chips are HP Precision Architecture, S SPARC, DEC Alpha, IBM Power, Motorola / IBM PowerPC Common RISC features. Load/store architecture (also called register-register or RR architecture) which fetches operands and results from the main memory through a lot of scalar registers. Other architecture is storage-storage or SS in which source operands and final results are retrieved directly from memory. Fixed length instructions which (a) are easier to decode than variable length instructions, and (b) use fast, inexpensive memory to execute a large piece of code. Hardwired controller instructions (as opposed to micro-coded instructions) This is where RISC really shines as a hardware implementation of directions is too faster and uses less silicon real estate than a microspore area. Fused or compound instructions which are heavily optimized for the most commonly used functions Pipelined implementations with an instruction (or more) per machine cycle. The large uniform register set minimum number of addressing modes no / minimum support for misaligned accesses NOT a requirement for either RISC or CISC instruction pipelining superscalär instruction dispatch hardwired or micro-coded Fused instructions Classical EP multiply Classical Fp Ladd 1. Addonant 2. Multiple significance 3. Normalize 4. Round off answer 1.Subtract exponents 2.Align decimal points by means of transfer of significance with the small exponent to right to get same exponent B. Add significance 4. Normalize 5 Round Classical instruction Fused instruction

PIPELINING     A conventional computer executes one instruction at a time with a Program Counter pointing to the instruction currently being executed Pipelining is analogous to an oil pipeline where the first result comes out. This provides a way to start a new product
the most difficult to guess. the worse case is that we will guess 1/3*/2 of conditional branches wrong, causing bubbles about 50 percent of the time.