C Programming (Turbo C++ Compiler) - Terminate and Stay Resident Program (TSR) Scrolling Text Sample

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I have given here a sample program for TSR which stands for Terminate and Stay Resident. It is easy to implement but you need to know about interrupt service routines and their functions.

TSRScrol.EXE -i "welcome to softwareandfinance.com" will install the scrolling text.
TSRScrol.EXE -u will stop the scrolling text.

Source Code

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#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <dos.h>

#include <conio.h>

#include <bios.h>

 

#define INTR 0X1C

 

#ifdef __cplusplus

    #define __CPPARGS ...

#else

    #define __CPPARGS

#endif

 

char far *scr=(char far*)0xB0008000L;

 

void interrupt ( *oldhandler)(__CPPARGS);

 

int count=0;

 

char message[64];

int len = 0;

struct  time t;

 

void interrupt handler(__CPPARGS)

{

        static int delayctr = 0;

        static int begpos = 0;

        int endpos = 79 - len;

 

        int i = 0;

        char far *p = scr;

 

        if(++delayctr > 5)

        {

                delayctr = 0;

        }

        else

        {

                oldhandler();

                return;

        }

 

 

        for(i = 0; i < begpos; i++)

        {

                p++;

                p++;

        }

        for(i = 0; i < len; i++)

        {

                *p++ = message[i];

                *p++ = 0x00;

        }

 

        p = scr;

        begpos++;

 

        if(begpos == endpos)

                begpos = 0;

        for(i = 0; i < begpos; i++)

        {

                p++;

                p++;

        }

 

        for(i = 0; i < len; i++)

        {

                *p++ = message[i];

                *p++ = 0x4f;

        }

 

        oldhandler();

}

 

 

int main(int argc, char *argv[])

{

        if(argc <= 1)

        {

                printf("Syntax: TSRScroll -I \"Message\" (for Install)\n");

                printf("Syntax: TSRScroll -U (for Uninstall)\n");

                return 0;

        }

 

        strcpy(message, argv[2]);

        len = strlen(message);

 

        if(argv[1][1] == 'I' || argv[1][1] == 'i')

        {

                printf("Installing...\n");

                oldhandler = getvect(INTR);

                setvect(INTR, handler);

                setvect(32, oldhandler);

                printf("Done\n");

        }

        else

        {

                printf("Uninstalling...\n");

                oldhandler = getvect(32);

                setvect(INTR, oldhandler);

                printf("Done\n");

        }

 

   return 0;

} 

Click here to download the source code and .EXE application

Output

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