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

Cache memory-microprocessor, Cache Memory Caching is a technology based...

Cache Memory Caching is a technology based on the memory subsystem of any computer. The majoraim of a cache is to accelerate the computer while keeping the cost of the computer

Develop an assembly language program, • To develop an assembly language pro...

• To develop an assembly language program to control a "simulated" intelligent domestic lighting system with the intention of deterring burglary. • To produce a schematic circuit d

Write a mips assembly language program, Write a MIPS/SPIM assembly language...

Write a MIPS/SPIM assembly language program that prints the smallest and largest values found in a non-empty table of N word-sized integers. The address of the first entry in your

Int n-unconditional branch instruction-microprocessor, INT N : Interrupt T...

INT N : Interrupt Type N:- In the interrupt structure of 8086/8088, 256 interrupts are distinct equivalent to the types from OOH to FFH. When an instruction INT N is executed,

General bus operation-microprocessor, General Bus Operation The 8086 ha...

General Bus Operation The 8086 has a joined data and address bus commonly referred to as a time multiplexed address and data bus. The major reason behind  multiplexing address

Port mapped or mapped input output, Port Mapped I/O or I/O Mapped I/O I...

Port Mapped I/O or I/O Mapped I/O I/O devices are mapped into a separate address space. This is generally accomplished by having a different set of signal lines to denote a mem

Develop a schematic circuit diagram of system, Develop a suitable schematic...

Develop a suitable schematic circuit diagram of your system showing the interface between the PIC16F84 and the existing mains light & switch, including 5V derivation from the 240V

Sub-arithmetic instruction-microprocessor, SUB: Subtract :- The subtract in...

SUB: Subtract :- The subtract instruction subtracts the source operand from destination operand and result is left in the destination operand. Source operand might be memory locati

Tabular comparison for micro processors parameters, Tabular comparison for ...

Tabular comparison for µ PS' Parameters Tables (a) and (b) list the characteristic of Intel microprocessor. Table(a):   Table(b): It has a 64 bit da

Merge Sort, Write a program to merge two sorted arrays to create a third so...

Write a program to merge two sorted arrays to create a third sorted array containing all values from the two original arrays. Merge is a key component to the mergesort algorithm.

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