PPT: Control Unit Operation | Computer Architecture & Organisation (CAO) - Computer Science Engineering (CSE) PDF Download

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Control Unit Operation
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Control Unit Operation
Micro-Operations
 Instruction execution
Øexecution of a sequence of steps, i.e., cycles
 Fetch, Indirect, Execute & Interrupt cycles
 Cycle - a sequence of micro-operations
 Micro-operations
Ødata transfer between registers
Øtransfer between a register & an external bus
ØALU operation
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Control Unit Operation
Micro-Operations
 Instruction execution
Øexecution of a sequence of steps, i.e., cycles
 Fetch, Indirect, Execute & Interrupt cycles
 Cycle - a sequence of micro-operations
 Micro-operations
Ødata transfer between registers
Øtransfer between a register & an external bus
ØALU operation
Control Unit Atomic Operations
 CU causes the processor to step through a series of
micro-operations in the proper sequence
 CU generates the control signals that cause each
micro-operation to be executed
 Micro-Operations are the atomic operations of the
Processor
 Control signals open & closes the logic gates
Ø transfer of data to & from the registers
Ø operation of the ALU
 Implementation of Control Unit
Ø Hardwired
Ø Microprogrammed, i.e., microinstructions
Page 4


Control Unit Operation
Micro-Operations
 Instruction execution
Øexecution of a sequence of steps, i.e., cycles
 Fetch, Indirect, Execute & Interrupt cycles
 Cycle - a sequence of micro-operations
 Micro-operations
Ødata transfer between registers
Øtransfer between a register & an external bus
ØALU operation
Control Unit Atomic Operations
 CU causes the processor to step through a series of
micro-operations in the proper sequence
 CU generates the control signals that cause each
micro-operation to be executed
 Micro-Operations are the atomic operations of the
Processor
 Control signals open & closes the logic gates
Ø transfer of data to & from the registers
Ø operation of the ALU
 Implementation of Control Unit
Ø Hardwired
Ø Microprogrammed, i.e., microinstructions
Constituent Elements of
Program Execution
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Control Unit Operation
Micro-Operations
 Instruction execution
Øexecution of a sequence of steps, i.e., cycles
 Fetch, Indirect, Execute & Interrupt cycles
 Cycle - a sequence of micro-operations
 Micro-operations
Ødata transfer between registers
Øtransfer between a register & an external bus
ØALU operation
Control Unit Atomic Operations
 CU causes the processor to step through a series of
micro-operations in the proper sequence
 CU generates the control signals that cause each
micro-operation to be executed
 Micro-Operations are the atomic operations of the
Processor
 Control signals open & closes the logic gates
Ø transfer of data to & from the registers
Ø operation of the ALU
 Implementation of Control Unit
Ø Hardwired
Ø Microprogrammed, i.e., microinstructions
Constituent Elements of
Program Execution Functional Specifications of a Processor
 Operations
 Addressing Modes Defined by the Instruction Set
 Registers – user visible
 I/O Module Interface Defined by the System
 Memory Module Interface Bus Specification
 Interrupts Defined by System Bus Specification
&
Operating System Support
Execution Time Sequence of Instructions
is not necessarily the same as the
Written Sequence of Instructions in the Program
(branching instructions)