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

Shl, Assume that the registers are initialized to EAX=12345h,EBX =9528h EC...

Assume that the registers are initialized to EAX=12345h,EBX =9528h ECX=1275h,EDX=3001h sub AH,AH sub DH,DH mov DL,AL mov CL,3 shl DX,CL shl AX,1 add DX,AX

Assignment, Write an assembly program that adds the elements in the odd ind...

Write an assembly program that adds the elements in the odd indices of the following array. Use LOOP. What is the final value in the register?

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,

Write program that will generate array of ten random number, 1. Write a pro...

1. Write a program that will generate an array of ten random 32-bit integers, and that will  display on the monitor the numbers followed by either the words " has the fourth bit se

Execution unit and bus interface unit-microprocessor, Execution Unit (EU) a...

Execution Unit (EU) and Bus Interface Unit (BIU) : 8086 consist of two processors called EU and BIU. Two Processors can work parallel. This improves speed of execution. BIU fi

Inc-arithmetic instruction-microprocessor, INC: Increment : - This instruct...

INC: Increment : - This instruction increments the contents of the particular memory or register location by the value 1. All the condition code flags are affected except the carry

Selecting array elements, implement the following c++ code in assembly lang...

implement the following c++ code in assembly language using the block-structured .IF and .while directives

Nible, calculate the number of one bits in bx and complement an equal numbe...

calculate the number of one bits in bx and complement an equal number of least significant bits in ax hint use the xor instruction

Addsub, Using the AddSub program from Ch3 under c:\Masm615\examples as a re...

Using the AddSub program from Ch3 under c:\Masm615\examples as a reference, write a program that subtracts three 16-bit integers using only registers. Insert a call DumpRegs statem

Overview of intel pro-pentium, Overview of Intel Pro-Pentium : The 2 c...

Overview of Intel Pro-Pentium : The 2 chief players in the PC CPU market are Motorola and Intel.  Intel has enjoyed incredible success with its processors since the early 1980

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