Count the number of bytes:
Modify any one of the last three programs, to also count the total number of bytes actually copied, the count should appear in a register. I suggest you set a breakpoint at the INT 20 instruction, because the registers can be reset if the INT 20 instruction is allowed to execute.
To modify a program to count the total number of bytes actually copied, you would need to make changes to the code where the copying of bytes occurs. Since you mentioned setting a breakpoint at the INT 20 instruction, I assume you are referring to Assembly language programming.
Here's a general approach to achieve this task:
1. Open the program you want to modify in an Assembly language editor or IDE.
2. Locate the section of code where the actual copying of bytes takes place.
3. Add a counter variable to keep track of the total number of bytes copied. This can be done by declaring a new register or memory location to store the count.
4. Initialize the counter variable to zero before the copying starts.
5. For every byte that is copied, increment the counter variable by one. This can be done using the appropriate instructions for incrementing the chosen register or memory location.
6. After the copying is completed, the counter variable will hold the total number of bytes copied.
To set a breakpoint at the INT 20 instruction and prevent the registers from being reset, you can use a debugger specific to the Assembly language environment you are working with. Here's a general approach using a typical Assembly language debugger:
1. Open the debugger tool and load the modified program.
2. Set a breakpoint at the INT 20 instruction using the debugger's breakpoint feature. The specific command or method to set breakpoints may vary depending on the debugger you are using. Consult the documentation of your debugger for the exact steps.
3. Execute the program in the debugger and allow it to run until it hits the breakpoint.
4. At the breakpoint, check the value of the counter variable to see the total number of bytes copied.
Remember, the specific instructions and syntax may vary depending on the target architecture and Assembly language used in your program. Make sure to refer to the appropriate documentation and references for the Assembly language you are using.