CS 301 Fall 2001

1
CS 301 Fall 2001 Chapter 3

• Slides by Prof. Hartman, following IBM PC
  Assembly Language Programming by Peter Abel

2
Using DEBUG

• Tutorial on the web.
• Appendix C in the book.
• DEBUG is not case sensitive.
• All numbers are hexadecimal.
• Spaces are used to separate parameters.
• Segments and offsets are specified as
  segmentoffset.

3
DEBUG Commands

• A Assemble instructions
• C Compare two areas of memory
• D Display contents of memory
• E Enter data into memory
• F Fill memory
• G Run the executable in memory. (Go)
• H Perform hexadecimal arithmetic
• I Input and display one byte from a port.
• L Load a file or disk sectors into memory.
• M Move (or copy) memory

4
DEBUG Commands 2

• N Name a program
• O Output a byte to a port
• P Proceed (execute CALL, LOOP, INT or REP)
• Q Quit
• R Display the contents of one or more registers
• S Search memory
• T Trace the execution of one instruction
• U Unassemble (disassemble) machine code.
• W Write a (named, .COM) file to disk
• ? Display help screen

5
DEBUG Examples

• Work through examples in the text pages 3648.