Stack operation and interrupts in microprocessor, Computer Engineering

Assignment Help:

Let us review the operation of the stack within the 68HC11, the stack is a defined area of RAM which is last in first out register (LIFO) . Access to the stack is made via a stack pointer (SP). In the 68HC11 there is only one stack pointer and it is initialised by the LDS command. To transfer data onto the stack we can use the command PSHA or PSHB i.e. push register A or B onto the stack. To remove data simply pull it i.e PULA or PULB, likewise the index registers may be stacked  etc.

      PSHA Push A onto Stack
      PSHB  Push B onto Stack
      PSHX  Push X onto Stack
      PSHY  Push Y onto Stack
      PULA Pull A onto Stack
      PULB  Pull B onto Stack
      PULX  Pull X onto Stack
      PULY  Pull Y onto Stack

Every time data is 'Pushed' onto the stack the Stack pointer is decrements accordingly. The stack is used often by the micro controller for temporary holding data, if a subroutine occurs, the processor stacks the return address and upon the receipt of the RTS command, it pulls the return address automatically. During an interrupt the processor stacks the full details of itself i.e.

  SP    Condition code  
  SP-1    Accumulator A
  SP-2    Accumulator B
  SP-3    Index register X high
  SP-4    Index register X low
  SP-5    Index register Y high
  SP-6    Index register Y low
  SP-7    return address High
  SP-8    Return address Low 
  SP-9    Stack pointer after interrupt

Therefore great care should be taken when using the stack as during an interrupt or subroutine if you place data on the stack you must remove the data before you return from it.


Related Discussions:- Stack operation and interrupts in microprocessor

Comparison between centralized and distributed spc, Explain the principles ...

Explain the principles of operation of centralized SPC and distributed SPC and compare their performance. All the control equipment is replaced with a single processor that mus

What are the two phases in the advancement of linux, What are the two phase...

What are the two phases in the advancement of Linux? State some Applications of Open Source Systems? Finance Educational Data Storage and Management ERP (Ent

Difference between shadow and override in programming, Overriding tell us o...

Overriding tell us only the methods, but shadowing tells us the entire element.

What a header represents in CGI document, A Header in CGI document can repr...

A Header in CGI document can represent? A header into CGI document can show format of the document and the location if document used to various URL.

Explain the working of interpreter, Explain the working of Interpreter? ...

Explain the working of Interpreter? The Interpreter is a program that executes instructions written in a high-level language. There are two manners to run programs written in a

What is the difference between vb6 and vb.net, What is the difference betwe...

What is the difference between VB6 and VB.Net? 1,Object-based Language 2,Doesnot support Threading 3 Not powerful Exception handling mechanism 4,Does not having suppor

Computer network, how Hierarchical Routing implement in c or cpp

how Hierarchical Routing implement in c or cpp

Modus ponens rule, Modus ponens rule: In fact the general format for t...

Modus ponens rule: In fact the general format for the modus ponens rule is as follows: like if we have a true sentence that states the proposition A implies proposition B and

What is the system call available to change the personality, What is the sy...

What is the system call available to change the personality? The system call personality prefers to a method to modify its implementation domain in order that Linux can emulate

Which data structures used in language processing, Which structure can be u...

Which structure can be used as a criterion for classification of data structures used in language processing. And. Nature of a data structure, purpose of a data structure and l

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