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

Show the properties of text box, Q. Show the properties of Text Box? Th...

Q. Show the properties of Text Box? The tag is used to specify where user input is expected. It has several attributes, of which TYPE attribute is used to specify th

What are assets in adobe premiere pro, Question: a) What is the meanin...

Question: a) What is the meaning of the term CTI in Adobe Premiere Pro? b) What are assets in Adobe Premiere Pro? c) In Adobe Premiere Pro, what is the principal diffe

Explain various classes of datatypes of c, Explain various classes of datat...

Explain various classes of datatypes of C   Following are the main classes of data types in C language: 1.  Primary data types: Also called as fundamental/basic data types

Extension of propositional logic, Extension of propositional logic: Aw...

Extension of propositional logic: Away from proving  theorems directly, and the other main use for rewrite rules is to prepare a statement just for use before we search for th

The six various application of stack, The six several application of stack ...

The six several application of stack in computer application is: 1.  Conversion of infix to postfix notation and vice versa. 2.  Evaluation of arithmetic expression. 3.

Define cache line, Define cache line. Cache block is used to refer to a...

Define cache line. Cache block is used to refer to a set of contiguous address location of some size. Cache block is also referred to as cache line.

What are invisible components, They are light weight components that do no ...

They are light weight components that do no painting, but can take space in the GUI. This is mainly used for layout management.

Define micro routine and microinstruction, Define micro routine and microin...

Define micro routine and microinstruction. A sequence of control words corresponding to the control sequence of a machine instruction represents the micro routine for that ins

What are different queues used, 1.Local queue -is a actual queue 2.Clus...

1.Local queue -is a actual queue 2.Cluster queue -is a local queue that is called as throughout a cluster of queue managers 3. Remote queue -structure explaining a queue

What are advantages and drawbacks of flip-flop, What are advantages and dra...

What are advantages and drawbacks of flip-flop? Usually area of a Flip-flop for features in more than a latch. Power consumption is normally higher, because of the area and

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