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

8086 minimum mode system and timing-microprocessor, 8086 Minimum mode Syst...

8086 Minimum mode System and Timing In a minimum mode 8086 system, the microprocessor 8086 is operated in minimum mode by strapping its MN/MX pin to logic 1.All the control si

Cbw-cwd-arithmetic instruction-microprocessor, CBW: Convert Signed Byte to...

CBW: Convert Signed Byte to Word: This instruction converts a signed byte to a signed word. In other terms, it copies the sign bit of a byte to be converted to all of the bits in

How to write an assembly program-microprocessor, How to write an assembly p...

How to write an assembly program The initial step in writing an assembly language program is to identify and study the problem. After studying the problem, choose the logical m

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

Display triangular shape using stars, write an assembly program to display ...

write an assembly program to display triangular star like shape

Boolean and comparison instructions, what will be the value of EAX after fo...

what will be the value of EAX after following instructions execute? mov bx, 0FFFFh and bx, 6Bh

8254 programmable timer-microprocessor, 8254 Programmable Timer A diagr...

8254 Programmable Timer A diagram of Intel's 8254 interval event/timer counter is given in Figure. The 8254 consists of 3 identical counting circuits, per of which has GATE and

Convert from C to 8086 assembly language, Trying to convert small programs ...

Trying to convert small programs from C to 8086 assembly language using emu 8086 emulator. I converted to low level C, but struggling with converting to the Assembly language.

Ror-logical instruction-microprocessor, ROR : Rotate Right without Carry: ...

ROR : Rotate Right without Carry: This instruction rotates the contents of destination operand to the bit-wise right either by one or by the count specified in register CL, exclud

Power pc-microprocessor, Power Pc : A Power PC is a microprocessor des...

Power Pc : A Power PC is a microprocessor designed to meet a standard, which was combining designed by Motorola, Apple and IBM. The PowerPC standard specifies a common instruc

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