Amu_Ke_Fundye

Amu_Ke_Fundye Machine Instructions and  Addressing Modes Computer Instruction:   A binary code used for specifying micro operations for computer. Instruction Code:  Group of bits used to instruct the CPU to perform specific operation. Instructions are encoded as binary  instruction codes . Each instruction code contains of a  operation code , or  opcode , which designates the overall purpose of the instruction. The number of bits allocated for the opcode determined how many different instructions the architecture supports. Instruction Set:  Collection of instructions. Instruction Representation:  Each instruction has a unique bit pattern, but for human beings a corresponding symbolic representation has been defined. Instruction Cycles:  Instruction cycle consists of following phases Fetching an instruction from memory. Encoding the instruction. Reading the effective address from memory in case of the instruction having an indirect address.

Amu_Ke_Fundye ALU and Data Path The CPU can be divided into a data section and a control section. The   data section , which is also called the   datapath. Datapath The registers, the ALU, and the interconnecting bus are collectively referred to as the datapath.  Each bit in datapath is functionally identical.  The datapath is capable of performing certain operations on data items. The  control section  is basically the  control unit ,  which issues control signals to the datapath . Bus : A Bus is a collection of wires or distinct lines meant to carry data, address and control information. Data Bus : it is used for transmission of data. The number of data lines corresponds to the number of bits in a word. Address Bus : it carries the address of the main memory location from where the data can be accessed. Control Bus : it is used to indicate the direction of data transfer and to coordinate the timing of events during the transfer. PC (Pro