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

What is the benefit of using linq on dataset, The main aim of using LINQ to...

The main aim of using LINQ to Dataset is to run strongly typed queries on Dataset. Assume we want to combine the results from two Datasets, or we need to take a distinct value f

Define electronic data interchange, Electronic Data Interchange (EDI ) is u...

Electronic Data Interchange (EDI ) is used by companies for transactions that happen on regular basis to a pre-determined format. It is one of the electronic commerce technologies.

Give detail explanation about arithmetic micro-operations, Give detail expl...

Give detail explanation about Arithmetic Micro-operations These micro-operations perform some essential arithmetic operations on numeric data stored in the registers. These bas

Important parameters for transmitting data, For this project, we hope to us...

For this project, we hope to use the basic idea of InfraRed (IR) communication for our television in ES103.  In ES103, we have a Sony large-screen television that we hope to commun

What is the length of function code at user-command, What is the length of ...

What is the length of function code at user-command? Every menu function, push button, or function key has an associated function code of length FOUR (for example, FREE), which

Convert decimal number to ocatl number, Convert (177.25) 10 to octal A...

Convert (177.25) 10 to octal Ans. 177.25) 10 = (         ) 8 Firstly we take integer part Hence (177) 10 = (261) 8 Now as 0.25 x 8 = 2.00 and 0.00 x 8 = 0 Therefor

Illustrate cache dram, Q. Illustrate Cache DRAM? Cache DRAM (CDRAM) wh...

Q. Illustrate Cache DRAM? Cache DRAM (CDRAM) which is developed by Mitsubishi integrates a tiny SRAM cache (16Kb) on a generic DRAM chip. SRAM on the CDRAM can be used in two

Feature Extraction and clustering, Hi, It is a data mining project I have ...

Hi, It is a data mining project I have a CSV file that has numbers data set. The data set contains images of handwritten digits. Recognizing handwritten digits is already a mature

Processor, what is the difference between i5 and i7 processor?

what is the difference between i5 and i7 processor?

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