debugger

 
The debugger used is the TD.EXE 

Type  TD  filename.exe   ie    TD   mfp.exe

The debugger opens with the file mfp.exe loaded for debugging.

The source code of the exe program is displayed.

The leftmost column has 'dots' indicating that the line is for code.

One of the DOTS , at the beginning the first one, is replaced by an arrow.

This arrow is a pointer showing the current line which will be executed.

Use F7  &  F8 as necessary to single step in or single step over.

The arrow will move to the next line to be executed.

At the end of the program the Debugger will display the status of the exit condition.

This procedure of debugging is not truely debugging.It is called tracing the instruction sequence.

Debugging involves knowing the status of the CPU and Memory.

A display of CPU register contents and Memory contents is desirable.

To View the CPU contents 


	

type ALT+V to get the view pull down menu select CPU and press enter

A display window will appear, over the source code window, containing the following blocks.

CODE BLOCK -Left TOP containing

module being executed in betqween # ie #module name# CS:IP adress location of the code Instruction in Hexadecimal representation Labels/Memory Symbolic references if any Instruction in Mnemonic representation TO MODIFY - MOVE CURSOR OVER THE BLOCK AND LEFT CLICK THE BOX IS ACTIVATED AND SLIDER CONTROLS APPEAR USE SLIDER CONTROLS ON RIGHTSIDE OF BLOCK FOR UP AND DOWN USE SLIDER CONTROLS BOTTOM OF BLOCK FOR LEFT AND RIGHT RIGHT CLICK TO GET CHOICE MENU GOTO - CHOSEN CODE MEMORY CS:IP ADDRESS ORIGIN-PROGRAM ORIGIN CS:IP ADDRESS FOLLOW-CURRENT CS:IP ADDRESS CALLER-SHOW SYMBOLIC NAME OF CALLER ROUTINE ------ ------ ------ ------ ------ ------ ------ MOVE CURSOR BAR OVER CHOICE AND LEFT CLICK AN INPUT BOX APPEARS ENTER THE CHOICE HERE

REGISTERS BLOCK -MIDDLE TOP containing

DISPLAY OF ALL 8086 REGISTER CONTENTS TO MODIFY THE CONTENTS- MOVE CURSOR OVER REGISTER TO MODIFY MOUSE CLICK LEFT TO SELECT REGISTER RIGHT CLICK THE MOUSE FOR MODIFY MENU INCREMENT DECREMENT MOVE CURSOR OVER ONE OF MODIFY OPTIONS LEFT CLICK - MODIFICATION DONE IN CASE OF 'CHANGE' A BOX OPENS ASKING FOR NEW VALUES

FLAGS BLOCK -RIGHT TOP containing

DISPLAY OF ALL 8086 FLAGS CONTENT TO MODIFY THE CONTENTS- MOVE CURSOR OVER FLAG TO MODIFY MOUSE CLICK LEFT TO SELECT FLAG RIGHT CLICK THE MOUSE TO TOGGLE FLAG

DATA SEGMENTS(DS/ES) CONTENT BLOCK -LEFT BOTTOM containing

DISPLAY OF MEMORY CONTENTS OF SEGMENT SPECIFIED TO MODIFY THE CONTENTS- MOVE CURSOR OVER THE BLOCK AND LEFT CLICK THE BOX IS ACTIVATED AND SLIDER CONTROLS APPEAR USE SLIDER CONTROLS ON RIGHTSIDE OF BLOCK FOR UP AND DOWN RIGHT CLICK TO GET CHOICE MENU GOTO SEARCH NEXT CHANGE FOLLOW PREVIOUS ..... ..... MOVE CURSOR BAR OVER CHOICE AND LEFT CLICK

sSTACK SEGMENTS BLOCK -RIGHT BOTTOM containing

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