Interrupt table-how interrupt table processed-microprocessor, Assembly Language

Assignment Help:

Interrupt Table

Each interrupt level has a booked memory location, called an interrupt vector.  All these vectors (or pointers) are stored in the interrupt table. Table lies at linear address zero, or with 64KB segments, at 0000:0000. Every vector is two words long (4 bytes). The high word has the offset and the low word the segment of the INT handler.

How INT's are Processed :

Since there are 256 levels and each vector is 4bytes long so the table contains 1024 bytes (256*4=1024). The INT number is multiplied by four to fetch the address from the table.               

Whenever the CPU registers an INT it will push the FLAGS register to the stack and also push the IP and CS registers.  After that the CPU deactivates the interrupt system.  Then it acquires the 8-bit value the interrupting device sends and multiplies this by four to acquire the offset in the interrupt table. From this offset it acquires the address of the INT handler and carries over execution to this handler.

Usually the handler enables the interrupt system immediately to let interrupts with higher priority. Some devices also require a signal that the interrupt has been acknowledged. When the handler is stop (terminated) it might signal the 8259A PIC with an EOI (End of Interrupt). Then handler executes an IRET instruction.

 


Related Discussions:- Interrupt table-how interrupt table processed-microprocessor

Software interrupts-microprocessor, Software Interrupts Software interr...

Software Interrupts Software interrupts are the result of an INT instruction in an executed program.  It may be assumed as a programmer triggered event that immediately stops e

Explore debugger, add the contents of the defined memory locations 120, 133...

add the contents of the defined memory locations 120, 133, 122 using mov instruction in dosbox

Machine code, do you type assembly code or machine code instructions like b...

do you type assembly code or machine code instructions like b8 0100000 to add to register EAX straigt onto dos command line or do you have to same in a file and what extension woul

Flowchart, ALP to preform of two 16-bit numbers in register addressing mode...

ALP to preform of two 16-bit numbers in register addressing mode

Program for generate mips assembly code that runable on spim, Project Overv...

Project Overview In this series of projects you will write a compiler for a small subset of Pascal.  In this assignment, you will start writing the syntax analysis and code gen

Hold response sequence-microprocesssor, Hold Response Sequence The HOLD...

Hold Response Sequence The HOLD pin is examined at leading edge of each clock pulse. If it is received active line by the processor before T4 of the earlier cycle/during the T1

Add-arithmetic instruction-microprocessor, ADD:  Add :- This instruction ...

ADD:  Add :- This instruction adds an immediate contents of a memory location specified in the a register ( source ) or instruction to the contents of another register (destinat

Dma controller-microprocessor, DMA controller :     Steps in...

DMA controller :     Steps include in transferring a block of data from I/O devices (for example a disk) to memory: 1. CPU sends a signal to initiate disk transfe

Ddition, Write a program that performs the addition, subtraction, multiplic...

Write a program that performs the addition, subtraction, multiplications, division of the given operands. Perform BCD operation for addition and subtraction.

Embeded programming, i want to develop traffic light system so which kind o...

i want to develop traffic light system so which kind of software is needed to develop this project?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd