Aspect | Horizontal Microprogramming | Vertical Microprogramming |
---|---|---|
Microinstruction Structure | Microinstructions are simple and contain single control signals or operations. | Microinstructions are detailed and contain all control signals needed for an instruction or operation. |
Organization | Microinstructions are organized horizontally, with each bit or field representing a specific control signal. | Microinstructions are organized vertically, with each microinstruction containing all control signals for an instruction. |
Instruction Execution | Control signals are executed in parallel across multiple control lines or functional units. | Control signals are executed sequentially, with each microinstruction representing a complete set of control signals for an instruction. |
Complexity | Less complex microinstructions, suitable for CPUs with simple instruction sets or control requirements. | More complex microinstructions, suitable for CPUs with complex instruction sets or control requirements. |
Efficiency | Efficient for fast execution of individual control operations. | Offers flexibility for detailed control sequencing and coordination. |
Example | In a simple CPU, a horizontal microinstruction might activate the ALU, increment the program counter, and set flags in parallel. | In a more complex CPU, a vertical microinstruction might specify all control signals needed to execute a specific instruction, such as a LOAD or ADD operation, in sequence. |
Categories: BTech CS II Year
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