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

Timing diagram of minimum mode, give the explaination of timing diagram min...

give the explaination of timing diagram minimum mode memory write cycle

8086, to separate positive and negative numbers

to separate positive and negative numbers

Write an assembly language program, You are to write an assembly language p...

You are to write an assembly language program called subfaq.s that computes the generalized subfactorial function of nonnegative integer inputs i0 and n. The generalized subfactori

Test-logical instruction-microprocessor, TEST : Logical Compare Instructio...

TEST : Logical Compare Instruction: The TEST instruction performs bit by bit logical AND operation on the 2 operands. Each bit of the result is then set to value I, if the equival

Web services. , describes vertical and horizontal web services protocols. N...

describes vertical and horizontal web services protocols. Next, identify the similarities and differences between vertical and horizontal web services protocols. Finally, explain w

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

Program, write a program assembly language for adding two 3*3 matrix

write a program assembly language for adding two 3*3 matrix

Program that will display a list of the decades , Write an assembly languag...

Write an assembly language program that will display (print) a list of the Decades 2010, 2020, 2030... 2100 to the screen using a while loop.

Matrix addition, how to write the alp for matrix addition in microprocessor...

how to write the alp for matrix addition in microprocessor 8086?

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