super scalar
The time to execute a 3 clock cycle instruction in a 25MHz processor is 120ns. One clock cycle is 40ns, 1/25Mhz, so three of them are 120ns.
Fetch Decode Execute. This is the cycle that processors will follow. Fetch the Instruction, Decode it into machine code, Execute the commands
The instruction cycle is the basic operation cycle in a computer. This is what will take in data, process it and execute as required.
There are four phase of an instruction cycle namely: fetch; indirect; execute; write.
Bus cycle - clock cycles taken to complete one bus transaction. Instruction cycle - clock cycles taken to complete execution of one instruction
the Fetch-Execute cycle is the process by which a computer retrieves a programmed instruction from its memory, determines what actions the instruction dictates, and carries out those actions.
The fetch-execute cycle of a typical microprocessor involves fetching an instruction from memory, determining what actions the instruction requires it to do, and performing those actions. It is also simply called the Instruction Cycle.
The fetch-execute cycle.
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.
The most gaping advantage can be very easilly explained through example: Single core processors have a single thread, and can process a single set of instructions per clock cycle. This looks like this (Saying this processor can process 2 instructions a clock): (Note this is in an optimal setting where data is perfectly threaded) Clock 1: Instruction 1; Instruction 2; Clock 2: Instruction 3; Instruction 4; Clock 3: Instruction 5; Instruction 6; Clock 4: Instruction 7; Instruction 8; Dual-Core processing would do this same instruction set much quicker: Clock 1: Instruction 1; Instruction 2; Instruction 3; Instruction 4 Clock 2: Instruction 5; Instruction 6; Instruction 7; Instruction 8 In a perfectly threaded application, two equivilent-performance cores on a dual core processor would power through the work twice as quickly as a single-core model. A quad-core with these specs would do the entire instruction set in a single clock. Even if it isn't always a 2x increase, multiple-core procesors have a distinct advantage in a very large range of applications.
The most gaping advantage can be very easilly explained through example: Single core processors have a single thread, and can process a single set of instructions per clock cycle. This looks like this (Saying this processor can process 2 instructions a clock): (Note this is in an optimal setting where data is perfectly threaded) Clock 1: Instruction 1; Instruction 2; Clock 2: Instruction 3; Instruction 4; Clock 3: Instruction 5; Instruction 6; Clock 4: Instruction 7; Instruction 8; Dual-Core processing would do this same instruction set much quicker: Clock 1: Instruction 1; Instruction 2; Instruction 3; Instruction 4 Clock 2: Instruction 5; Instruction 6; Instruction 7; Instruction 8 In a perfectly threaded application, two equivilent-performance cores on a dual core processor would power through the work twice as quickly as a single-core model. A quad-core with these specs would do the entire instruction set in a single clock. Even if it isn't always a 2x increase, multiple-core procesors have a distinct advantage in a very large range of applications.
Fetch Execute Cycle A more complete form of the Instruction Fetch Execute Cycle can be broken down into the following steps: 1. Fetch Cycle 2. Decode Cycle 3. Execute Cycle 4. Interrupt Cycle 1. Fetch Cycle The fetch cycle begins with retrieving the address stored in the Program Counter (PC). The address stored in the PC is some valid address in the memory holding the instruction to be executed. (In case this address does not exist we would end up causing an interrupt or exception).The Central Processing Unit completes this step by fetching the instruction stored at this address from the memory and transferring this instruction to a special register - Instruction Register (IR) to hold the instruction to be executed. The program counter is incremented to point to the next address from which the new instruction is to be fetched. 2. Decode Cycle The decode cycle is used for interpreting the instruction that was fetched in the Fetch Cycle. The operands are retrieved from the addresses if the need be. 3. Execute Cycle This cycle as the name suggests, simply executes the instruction that was fetched and decoded