12-04-2013, 03:54 PM
INTERRUPT STRUCTURE OF 8086
[attachment=53006]
INTERRUPT RESPONSE
8086 Completes The Execution Of Current Instruction
Checks The Source Of Interrupt. If It Is Due To INTR Go To Next Step Else Go To Step 5
Checks The Interrupt Flag. If Its Set Go To Next Step Else Execute Next Instruction ____
4. It Acks Intrrupt By Sending INTA Signal To The Device. _
It Reads Interrupt Type Given By The Device During Second INTA Signal
It Pushes The Flag Register To Stack And Decrements Stack Pointer By 2
It Clears Interrupt Flag And Trap Flag
It Saves Return Address By Pushing The CS, Dec Sp By 2,push IP To Stack, Dec Sp By 2
Transfers Control To Start Of ISR. Address Of ISR Is Taken From IVT
Based On Which Of The 256 Interrupts Is Serviced
At The End Of ISR, IRET Has To Be Executed
Pops IP, Inc Sp By 2,pops CS, inc Sp By 2
11. It Pops flags Inc Sp By 2
12. Transfers Control Back To The Program Which Was Interrupted
[attachment=53006]
INTERRUPT RESPONSE
8086 Completes The Execution Of Current Instruction
Checks The Source Of Interrupt. If It Is Due To INTR Go To Next Step Else Go To Step 5
Checks The Interrupt Flag. If Its Set Go To Next Step Else Execute Next Instruction ____
4. It Acks Intrrupt By Sending INTA Signal To The Device. _
It Reads Interrupt Type Given By The Device During Second INTA Signal
It Pushes The Flag Register To Stack And Decrements Stack Pointer By 2
It Clears Interrupt Flag And Trap Flag
It Saves Return Address By Pushing The CS, Dec Sp By 2,push IP To Stack, Dec Sp By 2
Transfers Control To Start Of ISR. Address Of ISR Is Taken From IVT
Based On Which Of The 256 Interrupts Is Serviced
At The End Of ISR, IRET Has To Be Executed
Pops IP, Inc Sp By 2,pops CS, inc Sp By 2
11. It Pops flags Inc Sp By 2
12. Transfers Control Back To The Program Which Was Interrupted