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Fetching
involves the following steps:
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a) |
Contents of PC are placed on address bus
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b) |
READ signal is activated
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c) |
Data (instruction opcode) are read from RAM and placed
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on data bus
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d) |
Opcode is latched into the CPU’s internal instruction
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register
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e) |
PC is incremented to prepare for the next fetch from
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memory
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Execution
involves decoding the opcode and
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generating
control signals to gate internal registers in
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and
out of the ALU and to signal the
ALU to
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perform
the specified operation.
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