input
The Instruction Register (IR) stores the instruction currently being executed. In simple processors each instruction to be executed is loaded into the instruction register which holds it while it is decoded, prepared and ultimately executed.
Yes, the term "instruction cycle" refers to the process by which a computer retrieves, decodes, and executes a single instruction. This cycle typically includes several stages, such as fetch, decode, execute, and write-back, allowing the CPU to perform operations as directed by program instructions. Each instruction cycle is crucial for the overall functioning of the computer's processing capabilities.
First of all as we know the CPU comprises of The Registers,The ALU Unit and the Control Unit.Processing of the data is done in CPU Registers (an area or a memory where processing takes place). M.J.Flynn suggested these architectures for enhancing the computational speed of the computer: 1. Single Instruction Single Data (SISD): Single instruction is performed on a single set of data in a sequential form.Most of our computers today are based on this architecture.Von Neumann fits into this category.Data is executed in a sequential fashion (one by one). 2. Single Instruction Multiple Data (SIMD): Single Instruction is performed on multiple data.A good example is the 'For' loop statement.Over here instruction is the same but the data stream is different. 3. Multiple Instruction Single Data (MISD): Over here N no. of processors are working on different set of instruction on the same set of data.There is no commercial computer of this kind also these are used in Space Shuttle controlling computer (all the buttons you must have noticed in the control center). 4. Multiple Instruction Multiple Data (MIMD): Over here there is an interaction of N no. of processors on a same data stream shared by all processors.Now over here if you have noticed a lot of computers connected to each other and when they perform a task on the same data (data is then shared).If the processing is high it is called Tightly Coupled and Loosely Coupled vice-versa.Most Multiprocessor fit into this category.
Von Neumann architecture: This type of architecture has a single memory for data and instructions, and uses a single bus for communication. The CPU transparently fetches instructions and processes data in a sequential manner. Harvard architecture: Harvard architecture uses separate memory spaces for instructions and data, allowing simultaneous access to both. This type of architecture improves performance as it can fetch instructions and data simultaneously. RISC (Reduced Instruction Set Computing): RISC architecture uses a small set of simple instructions that can be executed in a single clock cycle, resulting in faster processing speed. It focuses on simplicity and efficiency in instruction execution. CISC (Complex Instruction Set Computing): CISC architecture utilizes complex instructions that can perform multiple operations, aiming to reduce the number of instructions executed. This architecture is designed to support a wide range of operations in a single instruction.
MISD stands for Multiple Instruction, Single Data. It is a classification in parallel computing where multiple instructions are executed on the same data stream simultaneously. This architecture is commonly used in SIMD (Single Instruction, Multiple Data) systems where a set of processors work on separate data elements.
"CISC" stands for Complex Instruction Set Computer, CISC processor can execute complex instructions in one or more clock cycles. It is meant to differentiate it from a RISC or Reduced Instruction Set Computer, which can only perform one simple instruction in (usually) one clock cycle. A CISC is meant to have many machine level commands carried out as part of a single assembly command. The assembly command is broken into a series of "micro-code" commands which are executed internal to the processor by a "micro-code sequencer".
The Flynn classification is a system used to categorize computer architectures based on the number of concurrent instruction streams and data streams they can handle. It includes four main categories: Single Instruction Single Data (SISD), Single Instruction Multiple Data (SIMD), Multiple Instruction Single Data (MISD), and Multiple Instruction Multiple Data (MIMD). This framework helps to analyze and design parallel computing systems by highlighting different processing capabilities. It is named after Michael J. Flynn, who introduced the classification in 1966.
An extremely simple thing called machine code. Im not insulting you with the extremely simple thing, that just means its easy for the computer to follow. Machine code tells the computer what to do and when to do it.
"SIMD, which stands for 'single instruction, multiple data,' is a process that allows the CPU to receive a single instruction and then execute it on multiple pieces of data rather than receiving the same instruction each time each piece of data is received."(Pg. 434, A+ Guide to Managing and Maintaining Your PC)
Flynn's taxonomy is used to categorize computer architectures. Considers the number of processors and the number of data paths incorporated into an architecture. The fours combinations of processors and data path are: SISD( Single instruction, single data stream) MISD( Multiple instructions, single data stream) SIMD (Single instructions, multiple data streams) MIMD( Multiple instructions, multiple data streams)
The lock prefix on the 8086/8088 prevents any other bus master from accessing the bus during this instruction, even if this instruction is a multiple access instruction. It assures atomicity and data consistency in a multi-computer environment, but only for a single instruction. It is generally used to manipulate a mutex or semaphore.
In the early days of computing, programs were serial, that is, a program consisted of a sequence of instructions, where each instruction executed one after the other. It ran from start to finish on a single processor.reference: http://code.google.com/edu/parallel/mapreduce-tutorial.html