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

Inc-arithmetic instruction-microprocessor, INC: Increment : - This instruct...

INC: Increment : - This instruction increments the contents of the particular memory or register location by the value 1. All the condition code flags are affected except the carry

PIC lights on, errorlevel -302 ;prevents error code for this...

errorlevel -302 ;prevents error code for this chipset __config 0x373A ;chip config PIC spec page 146 processor 16F877A ;chipset reset code

Multiplication using shift and add instruction, Multiply two numbers by usi...

Multiply two numbers by using shift and rotate instruction

Compute the fibonacci sequence - assembly program, Compute the Fibonacci se...

Compute the Fibonacci sequence - assembly program: Problem: Fibonacci   In this problem you will write a program that will compute the first 20 numbers in the Fibonacci sequ

Copy a string backwards, I can get it to copy the string but can''t get it ...

I can get it to copy the string but can''t get it to reverse it.

Interrupt system based on 8259 a-microprocessor, Interrupt System Based on ...

Interrupt System Based on Single 8259 A The 8259A is contained in a 28-pin dual-in-line package that need only a + 5-V supply voltage.  Its organization is shown in given figur

The pentium pro-micro processor, The Pentium Pro    Introduced in the ...

The Pentium Pro    Introduced in the year 1995, the Pentium Pro reflected  still  more  design  breakthroughs.  The Pentium Pro may process 3 instructions in a single clock cy

Program for game by using microcontroller 8051, I want to do a program as a...

I want to do a program as a game by using the Microcontroller 8051 with the assembly language, by using 4*4 keypad and its matrix display. I have to use the keypad for playing the

Program for dispaying lcd characters, #include"lcd.asm"       ; assembly fi...

#include"lcd.asm"       ; assembly file is included for displaying lcd characters Main: PORTA EQU 0xF80  ; PORTS PORTB EQU 0xF81 PORTC EQU 0xF82 PORTD EQU 0xF83 R

Prime finder - assembly program, Prime Finder - assembly program: Pro...

Prime Finder - assembly program: Problem:  Prime Finder   In this problem you will write a small program that tests whether a given integer is a prime number or not.  Let's

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