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Dos based TSR program to Disable-Enable floppy drives

Dos based TSR program to Disable-Enable floppy drives

#pragma inline /* dodn't remove this line */
#include "dos.h"
#include "stdio.h"
#include "conio.h"
#define SUCCESS 0XC0FF
#define FAILURE 0XC000
union REGS i,o;
void interrupt (*old)();
struct INTERRUPT


    {
    	unsigned bp,di,si,ds,es,dx,cx,bx,ax,ip,cs,fl;
};
void interrupt disk (struct INTERRUPT);
int tsrc;
unsigned our_psp;
void interrupt our_1c();
void interrupt (*prev_1c)();
void interrupt our_2f(struct INTERRUPT);
void interrupt (*prev_2f)();
main(int argc,char *argv[])


    {
    int far *ebptr;
    strupr(argv[1]);
    tsrc=strcmp(argv[1],"UNLOAD");
    if(tsrc!=0)


        		{
        i.x.ax=0xc000;
        int86(0x2f,&i,&o);
        if(o.x.ax!=SUCCESS)


            			{
            our_psp=getpsp();
            res();
            ebptr=MK_FP(our_psp,0x2c);
            freemem(*ebptr);
            printf("\Nofloppy v(1.0) Installed Successfully....\n");
            keep(0,2500);
            /* if u want to use automatic memory allocation use next line*/
            /*keep(0,(_SS+(_SP/16)-_psp));*/
            			}
            printf("\nfor unloading nofloppy use -> nofloppy unload \n");
            printf("\n Nofloppy v(1.0) already Loaded.....");
        }
        else


            		{
            i.x.ax=0xc000;
            int86(0x2f,&i,&o);
            if(o.x.ax==SUCCESS)


                {
                i.x.ax=0xc001;
                int86(0x2f,&i,&o);
                if(o.x.ax==FAILURE)
                printf("\nCannot uninstall Nofloppy v(1.0),another program on top\n");
                else
                printf("\nNofloppy ver(1.0) Uninstalled");
            }
            else
            printf("\nNofloppy ver(1.0) NOT IN MEMORY");
        }
        return 0;
    }
    res()


        {
        prev_1c=getvect(0x1c);
        setvect(0x1c,our_1c);
        prev_2f=getvect(0x2f);
        setvect(0x2f,our_2f);
        old=getvect(0x13);
        setvect(0x13,disk);
        return 0;
    }
    void interrupt disk(struct INTERRUPT r)


        {
        	if (_DL==0 || _DL==1)


            	{
            	asm clc;
            	asm pushf
            	asm pop r.fl
            	return;
            	}
            _ES=r.es;
            _DX=r.dx;
            _CX=r.cx;
            _BX=r.bx;
            _AX=r.ax;
            (*old)();
            asm pushf
            asm pop r.fl;
            r.ax=_AX;
            r.bx=_BX;
            r.cx=_CX;
            r.dx=_DX;
            r.es=_ES;
        }
        void interrupt our_1c()


            {
            (*prev_1c)();
        }
        void interrupt our_2f(struct INTERRUPT r)


            {
            if(r.ax==0xc000)


                {
                r.ax=SUCCESS;
                return;
            }
            if(r.ax==0xc001)


                {
                r.ax=uninstall();
                return;
            }
            asm pop bp
            asm pop di
            asm pop si
            asm pop ds
            asm pop es
            asm pop dx
            asm pop cx
            asm pop bx
            asm pop ax
            asm jmp cs:_prev_2f;
        }
        int uninstall()


            {
            if(our_1c==getvect(0x1c) && our_2f==getvect(0x2f)&&disk==getvect(0x13))


                {
                setvect(0x1c,prev_1c);
                setvect(0x2f,prev_2f);
                setvect(0x13,old);
                freemem(our_psp);
                return(SUCCESS);
            }
            else
            return(FAILURE);
        }