1. CSC235 - Visual Studio Tutorial
Running and Debugging MASM Assembly Language Programs

2. First Example
Copy the AddVariables folder from the shared drive to your computer
S:\ComputerScience\Carelli\CSC235\Examples\VisualStudio\AddVariables
Navigate into your new ‘AddVariables’ directory and double click on the file
Project235.sln
This will open the project in Visual Studio

3. Note: if you don’t see code as shown in this window, double-click on the .asm file here

4. Running AddVariables
To run the program, click on “Local Windows Debugger” (circled on the previous slide)
This will produce an output window as below:
Registers are output from the Irvine routine DumpRegs
WaitMsg causes the program to pause as shown
Note the value stored in EAX

5. Setting Breakpoints
A program can be halted at any point in its execution, allowing a user to view register and memory values
This is done by setting a breakpoint
Simply click in the margin next to a command you want to halt on
Once a breakpoint is set, begin execution as before
The program will pause when it reaches that point
see the next slide…

6. 2 1: set the breakpoint 1 3 2: start the run (Local Windows Debugger)
3: execution pauses at the selected command
Note: changes to Continue 1 2 3

7. Debug Mode You are now in Debug Mode You have some choices: you can
add another breakpoint
… then, click on continue (see last slide)
program proceeds to next break point
Or..
single step though the code
progress one command at a time (next slide)

8. 1: click here to single-step
2: program executes one instruction and advances to the next 1 2

9. Monitoring Registers
While in Debug Mode, you can view changes to Registers
Debug->Windows->Registers
This will open a window for viewing the registers (next slide)
NOTE: you MUST do this while you are in Debugging mode!!!!

10. 1: Registers Window
2: Changes to Register values appear in red after every instruction
Note: right click in the Registers Window and check Flags to view flag settings

11. Monitoring Memory
While in Debug Mode, you can view changes to Memory values
Debug->Windows->Memory
This will open a new tab for viewing memory locations (next slide)
You can open up to 4 tabs
NOTE: you MUST do this while you are in Debugging mode!!!!

12. New tab for viewing memory locations
Click on it to get to memory view
(next slide)

13. To view a memory location
Type in & and the label for the memory location (&finalVal)
Memory address of that location is displayed
The contents of that location will be displayed as bytes
value of finalVal is h
Note how it takes up 4 bytes and is in Little Endian order!

14. Do it yourself
Try setting a breakpoint as shown, then step through the program
Watch the registers get updated in the Registers Window as each command executes
Set up and go to the Memory tab and see the value of finalVal get updated
note the Little Endian storage!