Basically the function of execution unit in 8086 is to perform all arithmetic and logic operations.It tells the Bus Interface unit(BIU) where to fetch instructions and data from.It has 4 components:Control circuitry,ALU,Flag registers and general purpose registers.
1.control circuits-it directs all the internal operations.
2.ALU-performs all logic operations.
3.general purpose registers-used to store data during execution.
4.flag registers-it has a 16bit flag register containing 9 flags that are set for certain conditions during any operation.Ex.carry flag(whenever there is a carry).
It also has a decoder to decode the fetched instructions.
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.
Intel 8088 Intel 8086 Intel 286 Intel 386 Intel 486 Intel Pentium Intel Pentium II Intel Pentium III Intel Pentium IV Intel Itanium Motorola 6800 Zilog Z80
biu stands for bus interface unit and eu stands for execution unit. In 8086 microprocessor BIU fetches the instructions and places in the queue. The Eu executes the fetched instruction and places the result in the registers
biu stands for bus interface unit and eu stands for execution unit. In 8086 microprocessor BIU fetches the instructions and places in the queue. The Eu executes the fetched instruction and places the result in the registers
In the 8086/8088, the execution unit is the part of the processor known as the CPU. It executes the instructions and generates the results. The bus interface unit, on the other hand, is the part of the processor that handles reading and writing to memory. The two are somewhat loosely coupled, with the bus interface unit attempting to always be ahead of the execution unit, i.e. using the cache, so that the execution unit's wait time is minimized and performance is maximized.
It depends on which pentium. The first pentiums had one execution unit. Later pentiums, such as the IV-HT, had two.
The 8086 CPU is a massive control unit itself. There are millions of transistors and other components and to give a circuit diagram would take thousands and thousands of pages. The copyright of the design belongs to Intel and it is illegal to publish it anyway.
The 8086/8088 is comprised of two major subsystems; the execution unit (EU), and the bus interface unit (BIU). They are relatively uncoupled, so they can run somewhat independently of each other. The EU is responsible for executing all of the instructions, while the BIU is responsible for processing the requests from the EU to and from external memory. By separating these two major functions, Intel achieved two goals. First, they were able to provide two versions of the same processor, one on an 8-bit bus (the 8088), and the other on a 16-bit bus (the 8086). Both EU's are the same, a 16-bit processor. The two flavors allow the system designer to choose the level of simplicity versus the level of performance. Second, by decoupling the EU from the BIU, the BIU is now able to start fetching instructions from memory, while the EU is busy processing the previous instruction. Depending on the mix of instructions, the BIU is theoretically capable of having the next instruction already fetched and available by the time the EU needs it. This boosts performance.
Because that's how Intel designed it. They chose a 6 byte queue in the 8086 in order to optimize speed versus latency of the execution unit versus the bus interface unit. The decision for 6 bytes, as compared to 4 or 8 or some other number was a cost tradeoff and a recognition of the average mix of instruction execution cycle times in a typical processing thread.
A microprocessor is a chip that serves as the central processing unit (CPU) in personal computer(PCs). it is often called a logic chip or master chip. it controls all programs and performs arithmetic calculations with great accuracy. it acts as the 'brain' of the computer. example:- Intel 4004 , Intel 8080 , Intel Pentium Pro , Pentium Microprocessor.
The 8086/8088 instruction queue is a buffer that holds opcode bytes that have been prefetched by the bus interface unit. This speeds up operations of the processor by helping to reduce fetch latency, i.e. to improve the probability that an opcode byte fetched by the processor is already available.
The Intel 80486.