RISC Vs Cisc Case Study

2/15/13

RISC vs. CISC

T he simplest way t o examine t he advant ages and disadvant ages of RISC arc hit ec t ure is by c ont rast ing it wit h it 's predec essor: CISC (Complex Inst ruc t ion Set Comput ers) arc hit ec t ure.
Multiply ing Two Numbers in Memory
On t he right is a diagram represent ing t he st orage sc heme f or a generic c omput er. T he main memory is divided int o loc at ions numbered f rom (row) 1: (c olumn) 1 t o (row)
6: (c olumn) 4. T he exec ut ion unit is responsible f or c arrying out all c omput at ions.
However, t he exec ut ion unit c an only operat e on dat a t hat has been loaded int o one of t he six regist ers (A, B, C, D, E, or F ). Let 's say we want t o f ind t he produc t of t wo numbers
The C ISC Approach
T he primary goal of CISC arc hit ec t ure is t o c omplet e a t ask in as f ew lines of assembly as possible. T his is ac hieved by building proc essor hardware t hat is c apable