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

Dec-micro processor, DEC : A powerful new Alpha 64 bit RISC computer ch...

DEC : A powerful new Alpha 64 bit RISC computer chip was introduced in the year 1977, as new VAX (Virtual Address Extension) Computer. The VAX was 32 bit computer line based on

Code, 1. Assembly code for the flow chart we did in the class about the sim...

1. Assembly code for the flow chart we did in the class about the simple I/O interface driver 2. Enhanced driver (flow chart and its assembly code) to cater for interruptions in th

Assembly Language Programming, Write a program that defines symbolic consta...

Write a program that defines symbolic constants for all of the days of the week

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

Entering a program-microprocessor, Entering a Program In this section, ...

Entering a Program In this section, we will explain the procedure for entering a small program on IBM PC with DOS operating system. Assume a program of addition of 2 bytes, as

Rcr-rcl-logic instruction-microprocessor, RCR: Rotate Right through Carry:...

RCR: Rotate Right through Carry:- This instruction rotates the contents  bit-wise of the destination operand right by the specified count through carry flag (CF). For each operati

Interrupt table-how interrupt table processed-microprocessor, Interrupt Tab...

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

Queue operation-microprocessor, Queue Operation :   RQ/CT0, RQ...

Queue Operation :   RQ/CT0, RQ/G1-Request/Grant:   These pins are utilized by other local bus masters, in themaximum mode, to force the processor to release the loca

Cache controller-microprocessor, Cache controller The cache controller ...

Cache controller The cache controller is the mind of the cache.  Its responsibilities include:  performing the  snarfs and snoops, updating the  TRAM  and SRAM and implementing

Risc characteristics-microprocessor, RISC Characteristics : The  concep...

RISC Characteristics : The  concept  of  RISC  architecture  include  an  attempt  to  reduce  execution  time  by make  simple  the instruction set of the computer. The main c

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