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

Quarters, There are two parts to this assignment. The first part has you r...

There are two parts to this assignment. The first part has you reading 4 integers representing; #QUARTERS, #DIMES, #NICKELS & #PENNIES, respectively. Your program should compute t

Instructions, Difference between div and idiv

Difference between div and idiv

Architecture of 8088-microprocessor, Architecture Of 8088 The register ...

Architecture Of 8088 The register set of 8088 is accurately the same as in to 8086. The architecture of 8088 is also same to 8086 except for 2 changes; a) 8088 has 4-byte instr

Internal hardware-interrupts-microprocessor, Internal Hardware-Interrupts ...

Internal Hardware-Interrupts Internal hardware-interrupts are the outcome of sure situations that occur during the execution of a program, for example. Divide by 0. The interru

Assembly language assignment, The main objective of the assignment is to ex...

The main objective of the assignment is to explore the knowledge regarding parallel ports of a computer system. You can read and write datato/from the parallel port using IN and OU

Program on fibonacci series , Write a program to calculate the first 20 num...

Write a program to calculate the first 20 numbers of Fibonacci series. Use the stack (memory) to store the calculated series. Your debugger output should look like the following sc

Aas-arithmetic instruction-microprocessor, AAS: ASCII Adjust AL After Subt...

AAS: ASCII Adjust AL After Subtraction AAS instruction correct the result in the AL register after subtracting operation of two unpacked ASCII operands. The result is in unpacked

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

Ret-unconditional branch instruction-microprocessor, RET : Return from the...

RET : Return from the Procedure:- At each CALL instruction, the register IP and register CS of the next instruction is pushed to stack, before the control is transferred to the

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