03:21
CONTROL UNIT
a digital computer is a general purpose digital system. a general-purpose digital computer is capable of executing various operations and in addition, can be instructed as to what specific sequence of operations it must perform. the user of such a system can control the process by means of a program, that is, a set of instructions that specify the operation, operands and the sequence by which processing task may be altered simply by specifying a new program with different instruction or specifying the instructions with different data. a computer instruction is a binary code that specifies a sequence of micro-operations for the computer. instruction codes together with data are stored in memory. the control unit fetches an instruction from main memory by sending an address and a READ command to the main memory. the instruction word comes from memory in the control unit. the construction which is in binary-code is then decoded by logic circuits in the control unit to determine which operation is to be performed. once this is determined, the control unit generates the signals needed to actually execute the operation.
thus, we can say that the control unit's function is to fetch, decode and execute the instruction that are in memory. the control unit contains logic and timing circuits that generate the signals needed to execute each instruction of a program one by one. the control unit performs these same steps till the last instruction of the program is executed. it directs and coordinates the operation of all the other parts of the computer by providing timing and control signals.
.jpg)
No comments
Post a Comment