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Chapter 6 Programming

Abstract

Covered in Lecture 6, 2022.7.16
Topics:
1. Structured Programming
2. Debugging

Structured Programming

The larger tasks are systematically broken down into smaller ones, which is called systematic decomposition.
There are basically 3 constructs for doing this.

  • sequential construct: carry out the first subtask completey, then go to the second. Never go back.
  • conditional construct: the task consists of doing one of 2 subtasks but not both, depending on some condition.
  • iterative construct: the task consists of doing a subtask a number of times as long as some condition is true.

construct.png

code.png

Debugging

The debugging program should be able to

  • Write values into memory locations and registers.
  • Execute instruction sequences in a program.
  • Stop execution when desired.
  • Examine what is in memory and registers at any point in the program.

common errors:

  • incorrectly setting the loop times.
  • confusing LDI and LD.
  • forgetting the CC so BR tests the wrong condition.
  • corner cases.

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