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

Program to convert decimal to binary number, Program is written but has err...

Program is written but has errors returning values from the procedure.

Totorial, How can i starting with Assembly langauge?

How can i starting with Assembly langauge?

Ocw-microprocessor, There are 3 kinds of OCWs. The command word OCWI is u...

There are 3 kinds of OCWs. The command word OCWI is utilized for masking the interrupt requests; when the mask bit corresponding to an interrupt request is value 1, then the requ

Matlab?., Hello, I just want to know how much would it cost for you to deve...

Hello, I just want to know how much would it cost for you to develop , debug and test a program in matlab to solve a system of equations with gauss elimination with partial pivotin

Iret-loop-unconditional branch instruction-microprocessor, IRET : Return f...

IRET : Return from ISR:- When an interrupt service routine is called, before transferring control to it, the IP, CS  register and flag registers are stored in the stack to ment

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

Control transfer or branching instruction-microprocessor, Control Transfer ...

Control Transfer or Branching Instruction Control transfer instructions transfer the flow of execution of the program to a new address specified in the instruction indirectly o

Seg-segment-assemblers directive-microprocessor, SEG : Segment of a Label:...

SEG : Segment of a Label:- The SEG operator is which is used to decide the segment address of the, variable, label or procedure and substitutes the segment base address in plac

Mmm development board, Write an account of your findings and produce a repo...

Write an account of your findings and produce a report containing all aspects of the above. Include a step-by-step 'simple User Guide' so that your program can be operated as inten

Write an assembly program to simulate a microwave, 1. The microwave has a c...

1. The microwave has a clock (hh:mm:ss am/pm) and the user should be able to change the clock at any time. 2. For cooking the user should first enter the time. The user can ente

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