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

Register organization of 8086-microprocessor, Register Organization of 8086...

Register Organization of 8086 8086  has  a great  set  of registers  containing  special  purpose and general  purpose  registers.  All the 8086 resisters are 16-bit registers.

Project, Any small project which can implement on any software. No need any...

Any small project which can implement on any software. No need any external hardware approach.

Pin functions of 8086-microprocessor, Pin functions for the minimum mode o...

Pin functions for the minimum mode operation of 8086 are following: 1) M/I/O -Memory/IO: This is a status line logically equivalent to S2 in maximum mode. When it is low, it

Cryptography, Write a program that allows a user to encrypt/decrypt a mess...

Write a program that allows a user to encrypt/decrypt a message using a shift cipher. The user should specify the key and the message. Your program should be able to handle messa

ADDITION-SUBTRACTION, HELLO I AM TRYING TO ADD AND SUBTRACT BUT I SEEM CAN'...

HELLO I AM TRYING TO ADD AND SUBTRACT BUT I SEEM CAN''T FIND THE CORRECT REGISTER TO PUT IN

Instruction set of 8086-microprocessor, Instruction set of 8086 : The 8...

Instruction set of 8086 : The 8086/8088 instructions are categorized into the following major types. This section describes the function of each of the instructions with approp

Any project ideas plz, can any one help me in my project by using assembly ...

can any one help me in my project by using assembly language

Machine level programs-microprocessor, Machine Level Programs In this s...

Machine Level Programs In this section, a few machine levels programming instance, rather then, instruction sequences are presented for comparing the 8086 programming with that

Div-idiv-arithmetic instruction-microprocessor, DIV: Unsigned Division:- T...

DIV: Unsigned Division:- This instruction performs unsigned division operation. It divides an unsigned word or double word by a 16-bit or 8-bit operand. The dividend might be in t

Counting Array Values(Programming exercises), Write an application that doe...

Write an application that does the following:(1) fill an array with 50 random integers; (2) loop through the array, displaying each value, and count the number of negative values;

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