An instruction pipeline is a technique used in the design of computers and other digital electronic devices to increase their instruction throughput (the number of instructions that can be executed in a unit of time).
execution and prefetching the instruction simultaneosly is called pipelining
Supserscaling and pipelining both increase instruction output. Superscaling also uses pipelining, however, superscaling allows for all the processes to be carried out at one time.
Scalar pipelining offers an alternative to vector pipelining whereby the cycles are used in a linear fashion. Vector pipelining performs vector computations.
In PIC Microcontroller , During the Fatching of instruction no. 1it needs of one clock cycle, then after for the exicution of instruction no. 1 it reqires one extra clock cycle , but at the same time it fatches inst. no. 2 . Similarly, during the execution time of inst. no. 2 , it fatches inst. no. 3 and so on.In other words we can say that, PIC Microcontroller requires 2 clock cycle at starting the after it requires only one clock pulse. In this way we can say that instruction pipelining is done in PIC microcontroller.
No. Pipeline processors are faster because they do not have to wait to fetch the next instruction, because the next instruction was "pre-fetched" already.
the very first advantage of piplene is that it is that it saves time in the execution of instruction because in pipeling there is overlapping of inst takes place.
With pipelining, the CPU begins executing a second instruction before the first instruction is completed. Pipelining results in faster processing because the CPU does not have to wait for one instruction to complete the machine cycle. The system clock is a small chip that the control unit relies on to synchronize computer operations. The faster the clock, the more instructions the CPU can execute per second. The speed at which a processor executes instructions is called clock speed. Clock speed is measured in megahertz (MHz), which equates to one million ticks of the system clock.
Difference between pipelining and vector processing?
Special restart instruction used with interrupts
holds the location of the current instruction, of course.
That is when parts of CPUs execute different parts of an instruction. Pipelining is implemented when the next operation is started as soon as the first part of the previous operation finishes. IE, the part that does a fetch operation is first. when it is done the fetch of the next instruction is started while the second operation is being executed in a different circuit. This causes many instructions to be in the 'pipeline' at once instead of waiting for the complete previous instruction to complete. For a more in depth explanation see the related link below.
1. FI (fetch instruction) - get the next instruction 2. DI (decode instruction) - decode the opcode and operands 3. CO (calculate operands) - calculate EA of the operands 4. FO (fetch operands) - fetch operands from memory (not necessary for register data) 5. EI (execute instruction) - execute instruction storing result if necessary 6. WO (write operand) - write the result in MEM
Intel 8086 has two separate units for fetching the instruction and executing the instruction. Thus while executing one instruction other instruction can be fetched. Thus it avoids the waiting time for the Execution Unit to receive other instruction. Bus Interface Unit (instruction fetching unit) stores the fetched instructions in a 6 level deep FIFO. This improves overall speed of the processor.
There is no pipelining concept in the 8085 microprocessor.It is only in the 8086 micro processor an advanced processor of the 8085.
CISC - Means Complex instruction set architecture. A CISC system has complex instructions such as direct addition between data in two memory locations. Eg.8085Instruction Set:large set of instruction with variable size (16 to 64)Addressing Modes: 12-24General Purpose registers: 8-24Clock rate: 33-50MHz in 1992RISC - Means Reduced Instruction Set Computer. A Risc system has reduced number of instructions and more importantly it is load store architecture were pipelining can be implemented easily. Eg.ATMEL AVRInstruction Set:Small set of instruction with fixed size (32-bit)Addressing Modes: 3-5General Purpose registers: 32-192Clock rate: 50-150MHz in 1993
A very limited form of parallelism is achieved by using pipelining in that several instructions (up to the limit of the depth of the pipeline) are being processed (each at a different stage of instruction processing) at the same time. An example of this using a 6 stage pipeline is as follows:instruction completion (this is the oldest instruction stage)data storage to memoryinstruction execution & perform input/outputdata read from memorymemory address resolutioninstruction fetch from memory (this is the newest instruction stage)This form of parallelism was first used in the IBM 7030 Stretch computer released in 1961 but did not become a common feature in computer architectures until the introduction of RISC in the 1980s. The main advantage of pipelining is that under normal conditions none of the instruction processing hardware becomes idle. The main disadvantage of pipelining is that unscheduled events (e.g. interrupts, branch mispredictions, arithmetic exceptions) cause pipeline content flushes and having to spend time reloading the now empty pipeline to resume correct processing.Some computers designed with pipelines having an unusually high number of stages had their performance so degraded by that disadvantage that real world benchmarks showed their performance to be only slightly better than the traditional nonpipelined computers, even though their estimated performance was originally much higher. RISC specified that the number of stages in the pipeline should be kept to a minimum to reduce this problem.
In persistent HTTP without pipelining, the browser first waits to receive a HTTP response from the server before issuing a new HTTP request. In persistent HTTP with pipelining, the browser issues requests as soon as it has a need to do so, without waiting for response messages from the server.
Instruction processing consists of several steps. Depending on the complexity (and cost) of the computer, some of these steps may be done concurrently:Fetch the instruction,decode instruction operation code to determine what it should do,resolve addressing modes based on the operation code to get operand addresses.Fetch data from registers or memory address.,execute instruction,Move results of instruction execution to memory address, register, or new instruction address (if it is a branch/jump instruction.Modern computers have the ability, while executing an instruction, to perform some of the above functions preparing the next instruction or instructions for execution. This preparing of the next instructions "coming down the pipe" for processing is called pipelining.The simple 8086, while executing one instruction, has a six byte instruction queue and the ability to fetch the next six bytes after the current instruction and prepare it for processing. Since instructions vary in size, as bytes are taken from this instruction queue, the next bytes are fetched from memory into the queue to reduce the memory fetch time for the next instruction. More sophisticated computers can prepare the next several instructions after the current instruction and prepare them for processing. Some advanced machines can pipeline up to the next 20 instructions (or more) and can even execute more than one instruction at the same time. If one of the instructions changes the instruction flow by branching to another part of memory, the rest of the pipeline is cleared and loaded from the new execution address. If when two instructions are executed simultaneously, the results of the first instruction will affect the next one, the results of the next instruction are cleared and its processing is restarted.The 8086 CPU has two main components. The Execution Unit (EU) tells the Bus Interface Unit (BIU) from where to fetch instructions as well as to read data. The EU gets the opcode of an instruction from an instruction queue and decodes it or executes it. The BIU and EU operate independently. While the EU is executing an instruction the BIU fetches instruction codes from memory and stores them in the queue. This type of overlapping operation of the BIU and EU functional units of a microprocessor is called pipelining.In the 8086/8088 there is a 6 byte instruction prefetch queue which is used to prefetch instruction bytes while the processor is working on processing earlier bytes. In this way, it is statistically possible that the next opcode can be fetched and available to the processor when it is done with the prior opcode and it wants the next opcode. This is called pipelining, or caching, and it can speed up processing. Of course, if the processor branches, the prefetched instruction bytes have to be discarded, but that's "the way the cookie crumbles." Modern processors actually have branch prediction algorithms to help this issue.
Beginner's All-purpose Symbolic Instruction Code