BIU : Bus interface Unit
It provides the interface of 8086 to external memory and I/O (Input/Output) device's via the system bus,It performs various machine cycle such as Read memory,Read I/O device etc.It transfer data between memory to I/O devices.
BIU Perform following functions :
- It generates 20 bit of memory address for memory access
- It fetches instructions from the memory
- It transfer data between memory to I/O device's
- Maintain 6 byte prefetch instructions.(Support Pipeline)
BIU Resistors
Instructions Pointer (IP) :
- IP is 16 bit resistor, It holds offset of next instruction in code segment.
- IP incremented after every instructions byte is fetched
- IP get new value whenever branch of instructions occurs
Code segment (CS) :
CS holds base address for code segment, All programs stored in code segment and Accessed via IP.
Stack Segment (SS) :
SS holds base of address for Stack segment.
Data segment (DS) :
DS holds base address for data segment.
Extra Segment (ES) :
ES holds base address for extra segment.
Tags:
MIC