All generation of microprocessor code#
All generation of microprocessor plus#

The EU includes an arithmetic and logic unit (ALU), a control unit, and a set of registers. It has no direct connection with the system and performs over data through BIU. The main function of the EU of the 8086 microprocessor is to control operations on data using an instruction decoder and ALU. The execution unit of the 8086 gives instructions to the bus interface unit stating from where to fetch the instructions or data from, decode the instructions, and execute those instructions. IP is responsible for holding the distance or offset from this address to the next instruction byte to be fetched. The Instruction Pointer is a 16-bit register. The string instructions always use the ES and destination index (DI) to determine the 20-bit physical address. The ES of the 8086 microprocessor is an additional data segment used by some strings to hold extra data.

All generation of microprocessor plus#

The current word in the stack that is addressed is indicated by the segment address plus an offset value in the stack pointer. The stack segment register of the 8086 microprocessor contains the starting address of a programвЂ™s stack segment. It is accessed in the data segment by an offset address or the content of the other register that holds the offset address. The data segment contains the starting address of the programвЂ™s data segment.

All generation of microprocessor code#

It finds its application in addressing a memory location in the code segment of the memory where the executable program is stored. The base of the current code segment is contained by the code segment register of the 8086 microprocessor. It also contains one pointer register IP. Ts holds the address of instructions and data in the memory which are used by the processor to access memory locations. The BIU of 8086 microprocessor has 4 segment buses i.e. Pipelining is the process of fetching the next instruction cycle when the current instruction is being executed. When the Execution unit executes an instruction and is ready for the next instruction, it simply reads the instruction from the instruction queue resulting in increased execution speed. BIU gets up to six bytes of the next instructions and stores them in the instruction queue.

The Bus Interface Unit of the 8086 microprocessor contains an instruction queue. The BIU of 8086 microprocessor has the following functional parts: 1. The BIU and EUВ are connected by an internal bus as shown in the block diagram above. The Execution Unit of the 8086 microprocessor has no direct connection to the system bus so this is possible with BIU. The Bus Interface Unit of 8086 microprocessor manages all the data and addresses transfers for the Execution Unit (EU) like sending address, fetching an instruction, reading data from the memory/ports as well as writing data to the ports/memory. 2.Execution Unit Bus Interface Unit (BIU) of 8086 Microprocessor