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Incorrect. Fetching and decoding of any instruction takes a minimum of four clock cycles in the 8085.
T1 = ALE and address emission
T2 = Read initiation
T3 = Read completion
T4 = Opcode decode
T1, T2, and T3 are repeated for each additional byte of the instruction. In all cases, Twait, if indicated by not READY, is inserted between T2 and T3.
What else can I help you with?
How many machine cycles do one byte instructions have?
Depending on the particular microprocessor, a machine cycle is the fetch or store of one (typically, one byte) native word. In the 8085, this is a byte fetch or store, plus the overhead in decoding and processing the instruction. In this case, the first machine cycle is four clock cycles, or T states, and subsequent machine cycles are three clock cycles, although certain instruction sequences, such as DAD, require two extra clock cycles.
How many fetch cycles a three byte instruction requires for its execution?
There are three fetch cycles in a three byte instruction. The first one is four clock cycles long, while the other two are three clock cycles long. Depending on what the instruction does, there will then be more read/write cycles.
Which is the longest instruction in 8085 instruction set?
CALL, requiring 18 clock cycles.
What no of instruction will be execute by using only one clock pulse in 8085 microprocessor?
There are no instructions in the 8085 that execute in only one clock pulse. The minimum number of clock cycles is four; three for instruction fetch and one for instruction decode/execute.
Which is the long instruction in 8085 instruction?
The CALL instruction uses 18 clock cycles. 3x3 fetch, 2x3 store, 1x1 decode, 2x1 decrement.
What are the key components and functions of the CPI in computer architecture?
The key components of the CPI (Clocks Per Instruction) in computer architecture are the clock cycle time and the number of instructions executed. The CPI measures the efficiency of a processor by indicating how many clock cycles are needed to execute an instruction. A lower CPI indicates better performance, as it means fewer clock cycles are needed to complete an instruction.
How many clock cycles does the CPU require to act on a command?
It depends on the processor. They often have a different number of Cycles per Instruction. (http://en.wikipedia.org/wiki/Cycles_Per_Instruction)
What is prefetch queue in 8086?
To speed up the program execution, the B.I.U fetches six instructions byte ahead of time from memory and stores in FIFO registers called "queue". Since EU and B.I.U are independent, the B.I.U fetches additional instruction, while EU decodes and executes a previously fetched instruction. When the execution unit is ready for its next instruction, it simply reads the instruction from the queue. The main point here is that, fetching of the next instruction is overlapped with the execution of current instruction. This is called pipe lining pipe lining saves time required for executing instructions. For example, if a multiplication operation is to be performed with its operands and registers, the microprocessor takes 100 clock-cycles, however, without pipe lining and with pipe lining, the number of clock cycles required to multiply two operands get relatively reduced. There are many instructions in 8086 microprocessor that require huge number of clock cycles. Thus, the prefetch queue becomes a circular part in enhancing the performance of the system.
What is NOP Instruction stands in 8085 microprocessor?
The NOP instruction is a no-operation instruction. It does nothing to the state of the machine, except to use some time. In the case of the 8085, it uses four clock cycles plus however many wait states are need to access the NOP instruction from memory.
What is the difference between bus cycle and instruction cycle?
Bus cycle refers to the process of transferring data between the CPU and memory or peripherals, while instruction cycle refers to the series of steps that the CPU goes through to fetch, decode, and execute instructions. In other words, bus cycle involves the movement of data, while instruction cycle involves the actual execution of instructions.
How many clock cycles will a 1.7 GHz computer have?
1.7 * 10^9 = Clock Cycles
How many instructions are executed per second in 8085 kit in microprocessor?
In order to determine the instructions per second in an 8085 microprocessor, you need to know how long each instruction takes to execute. Some are as short as 4 T cycles. Some are as long as 18 T cycles. This is dependent on how the program is written. Add up the T cycles for each instruction. Divide the clock frequency in hertz by the number of T cycles, and you get instructions per second. Note that clock frequency is one half of the crystal frequency. Note also that you must include Twait cycles in your calculation.
