Control Unit Question & Answers December 15, 2022 By WatElectronics This article lists 50 Control Unit MCQs for engineering students. All the Control Unit Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of the Control Unit. The processors use Boolean equations to define the control unit. The control unit generates control signals using hardware and a microprogrammed control unit. The hardwired control unit is implemented as logic circuits (gates, decoders, flip-flops, etc) in the hardware. The hardware control unit is fast because combinational circuits generate control signals. The disadvantage of the hardwired control units is they are more complex and modifications in control signal are very difficult. The instruction registers, two decoders, a four-bit sequence counter, and a number of control logic gates are the components of the hardwired control unit. A micro instruction in a microprogrammed control unit consists of one or more micro-operations to be executed and an address of the next microinstruction to be performed. The hardwired control unit is not flexible and is difficult to modify for new instruction. The speed of the hardwired control unit is fast and the cost of implementation is more. The microprogrammed control unit is flexible, and new instructions can easily be added to the microprogrammed control unit. The RISC microprocessor is an application of hardwired control unit and the CISC microprocessor is an application of a microprogrammed control unit. The control memory is absent in a hardwired control unit and present in a microprogrammed control unit. The control unit controls the state of the instruction cycle whereas the sequencing and execution are the control unit functions. The clock, instruction register, flags, and control signals from the control bus are the inputs and control signals within the processor, and control signals to the control bus are outputs of the control unit. 1). Which one of the following control units is fast in speed? Hardwired control unit Microprogrammed control unit Both a and b None of the above None Hint 2). Which one of the following control unit is flexible? Hardwired control unit Microprogrammed control unit Both a and b None of the above None Hint 3). In which one of the following control unit, the cost of implementation is cheaper? Hardwired control unit Microprogrammed control unit Both a and b None of the above None Hint 4). In which one of the following control unit the ability to handle complex instruction is difficult? Hardwired control unit Microprogrammed control unit Both a and b None of the above None Hint 5). Which one of the following determines the enabling and sequencing of the operations? Control unit Datapath Both a and b None of the above None Hint 6). The control unit receives ____________________ signals? Status Control Both a and b None of the above None Hint 7). Which one of the following is a basic element of ASM chart? State box Vector decision box Both a and b None of the above None Hint 8). What is the standard form of CAR? Common Address Register Control Address Regulator Control Address Register None of the above None Hint 9). What is the standard form of SBR? Subroutine Register Small Register Simple Register None of the above None Hint 10). Which one of the following control units is not flexible? Hardwired control unit Microprogrammed control unit Both a and b None of the above None Hint 11). Which one of the following performs data transfer and processing operations? Control unit Datapath Both a and b None of the above None Hint 12). The control unit sends ____________________ signals? Status Control Both a and b None of the above None Hint 13). What is the standard form of HLL? High Level Language High Low Language Historic Level Language None of the above None Hint 14). Which one of the following is an instruction execution characteristic? High level language Execution sequencing Operands used All of the above None Hint 15). The addressing mode of register-to-register instruction type is _________________? Direct Immediate Register Register indirect None Hint 16). The addressing mode of load, store instruction type is ____________? Direct Immediate Register Register indirect None Hint 17). Which one of the following is a common characteristic of RISC? Register to register operations Simple instruction format Both a and b None of the above None Hint 18). What is the standard form of SSID? Single Instruction Stream, Single Data Stream Single Instruction Stream, Simple Data Stream Simple Instruction Stream, Single Data Stream None of the above None Hint 19). What is the standard form of WAR? Write After Reel Write After Real Write After Read None of the above None Hint 20). Which one of the following is a fundamental limitation to parallelism? Output dependency Anti-dependency True data dependency All of the above None Hint Control Unit MCQ for Quiz 21). The RORC is the mnemonic of __________________ instruction? Rotate right thru carry Right-right thru carry Rotate-rotate thru carry None of the above None Hint 22). Which one of the following comes under shift instruction? SHR CLR DIV None of the above None Hint 23). Which one of the following comes under logical and bit manipulation instruction? CDM SHL SHRA None of the above None Hint 24). The add with carry instruction comes under ___________________ type of instruction? Shift Arithmetic Logical and bit manipulation None of the above None Hint 25). What is the standard form of SIMD? Single Instruction, Multiple Data Stream Single Instruction, Simple Data Stream Simple Instruction, Single Data Stream None of the above None Hint 26). The rotate left thru carry comes under _____________ instruction? Shift Arithmetic Logical and bit manipulation None of the above None Hint 27). The branch if zero comes under ________________ instruction? Shift Arithmetic Control branch None of the above None Hint 28). What is the standard form of MAR? Memory Address Register Memory Add Register Main And Register None of the above None Hint 29). Which one of the following is an input to the control unit? Master clock signal Instruction registers Flags All of the above None Hint 30). What is the standard form of MISD? Multiple Instruction, Simple Data Stream Multiple Instruction, Simple Digital Stream Multiple Instruction, Single Data Stream None of the above None Hint 31). Which one of the following is an output to the control unit? Control signals to control bus Instruction registers Master clock register All of the above None Hint 32). The figure shown below is a block diagram of _______________? Instruction Register Control unit CPU None of the above None Hint 33). In which one of the following control unit, the decoding is easy? Microprogrammed Hardwired Both a and b None of the above None Hint 34). The RISC microprocessor is an application of ________________ control unit? Microprogrammed Hardwired Both a and b None of the above None Hint 35). What is the standard form of WAW? Write After Web Write Application Web Write After Write None of the above None Hint 36). The instruction set size is large in _____________________ control unit? Microprogrammed Hardwired Both a and b None of the above None Hint 37). In which one of the following control unit, control memories is present? Microprogrammed Hardwired Both a and b None of the above None Hint 38). The control functions in microprogrammed control unit implemented in _________________? Hardware Software Both a and b None of the above None Hint 39). The figure shown below is a block diagram of _______________? Instruction Register Hardwired based control unit Microprogrammed control unit None of the above None Hint 40). What is the standard form of MIMD? Multiple Instruction System, Multiple Data Stream Multiple Internal Stream, Multiple Digital Stream Multiple Instruction Stream, Multiple Data Stream None of the above None Hint Control Unit MCQ for Exams 41). Which one of the following control units require more chip area? Microprogrammed Hardwired Both a and b None of the above None Hint 42). The control functions in hardwired control unit implemented in _________________? Hardware Software Both a and b None of the above None Hint 43). In which one of the following control unit control memories is absent? Microprogrammed Hardwired Both a and b None of the above None Hint 44). The figure shown below is a block diagram of _______________? Instruction Register Hardwired based control unit Microprogrammed control unit None of the above None Hint 45). What is the standard form of RAW? Read After Write Real After Write Reel After Write None of the above None Hint 46). The branch if not zero comes under ________________ instruction? Shift Arithmetic Control branch None of the above None Hint 47). The C=1 is the tested condition of ______________ instruction? Branch if zero Branch if not zero Branch if carry None of the above None Hint 48). What is the standard form of GPU? Graphics Processing Unit Graphics Programmable Unit Graphics Pointer Unit None of the above None Hint 49). Which one of the following is a basic responsibility of control unit? Moving data between registers Regulating other internal operations Both a and b None of the above None Hint 50). What is the standard form of MBR? Memory Bus Register Memory Buffer Register Main Buffer Register None of the above None Hint Read more about Control Unit Please fill in the comment box below. Time's up
