Category : Files from Magazines
Archive   : TSR.ZIP
Filename : STAYXIT.420

{****************************************************************************}
{ S T A Y X I T . I N C }
{****************************************************************************}
{----------------------------------------------------------------------------}
{ Stay_Xit Check Terminate Keys }
{ }
{ Clean up the Program ,Free the Environment block, the program segment }
{ memory and return to Dos. Programs using this routine ,must be the }
{ last program in memory, else ,a hole will be left causing Dos }
{ to take off for Peoria. }
{----------------------------------------------------------------------------}
Procedure Stay_Xit;
{
This code reinstates those interrupts that will not be
restored by DOS. Interrupts 22,23,24 (hex) are restored
from the Current PSP during termination.
}
VAR
PSPvector22: vector absolute Cseg:$0A;
PSPvector23: vector absolute Cseg:$0E;
PSPvector24: vector absolute Cseg:$12;

DOSvector22: vector absolute 0:$88;
DOSvector23: vector absolute 0:$8C;
DOSvector24: vector absolute 0:$90;

Begin { Block }

Writeln ('Stay-Resident program Terminated') ;

Inline($FA); {Disable interrupts}

{ Restore Disk Interrupt Service Routine }

Regs.Ax := $2500 + BIOSI13;
Regs.Ds := BIOS_INT13.CS;
Regs.Dx := BIOS_INT13.IP;
Intr ($21,Regs);

{ Restore Keyboard Interrupt Service Routine }

Regs.Ax := $2500 + BIOSI16;
Regs.Ds := BIOS_INT16.CS;
Regs.Dx := BIOS_INT16.IP;
Intr ($21,Regs);

{ Restore Timer Interrupt Service Routine }

Regs.Ax := $2500 + BIOSI8;
Regs.Ds := BIOS_INT8.CS;
Regs.Dx := BIOS_INT8.IP;
Intr ($21,Regs);

{ Restore DOS 21 Interrupt Service Routine }

Regs.Ax := $2500 + DOSI21;
Regs.Ds := DOS_INT21.CS;
Regs.Dx := DOS_INT21.IP;
Intr ($21,Regs);

{ Restore DOS 28 Interrupt Service Routine }

Regs.Ax := $2500 + DOSI28;
Regs.Ds := DOS_INT28.CS;
Regs.Dx := DOS_INT28.IP;
Intr ($21,Regs);

{ Move Interrupt Vectors 22,23,24 to our PSP from where DOS will restore }

PSPvector22 := DOSvector22; { Terminate vector }
PSPvector23 := DOSvector23; { Cntrl-C vector }
PSPvector24 := DOSvector24; { Critical vector }

Inline($FB); {Re-enable interrupts}

Regs.Ax := $49 shl 8 + 0 ; { Free Allocated Block function}
Regs.Es := MemW[Cseg:$2C] ; { Free environment block }
MsDos( Regs ) ;

Regs.Ax := $49 shl 8 + 0 ; { Free Allocated Block function}
Regs.Es := Cseg ; { Free Program }
MsDos( Regs ) ;

End { StayXit };