Category : Files from Magazines
Archive   : ITP9003.ZIP
Filename : CATCHINT.PAS

PROGRAM CatchInt;

USES
Crt,Dos,Printer;

{This program illustrates how you can modify an
interrupt service routine to perform special
services for you.}

VAR
OldInt,OldExitProc: pointer;
IntCount: array[0..255] of byte;

PROCEDURE GoOldInt(OldIntVector: pointer);
INLINE (
$5B/ {POP BX - Get Segment}
$58/ {POP AX - Get Offset}
$89/ {MOV SP,BP}
$EC/
$5D/ {POP BP}
$07/ {POP ES}
$1F/ {POP DS}
$5F/ {POP DI}
$5E/ {POP SI}
$5A/ {POP DX}
$59/ {POP CX}
$87/ {XCHG SP,BP}
$EC/
$87/ {XCHG [BP],BX}
$5E/
$00/
$87/ {XCHG [BP+2],AX}
$46/
$02/
$87/ {XCHG SP,BP}
$EC/
$CB); {RETF}


{$F+}

PROCEDURE NewExitProc;

VAR I: byte;
VAR A: char;

FUNCTION Intr21Desc(IntNbr: byte): string;

VAR
St : string[30];

BEGIN
CASE IntNbr of
$25: St := 'Set Interrupt Vector';
$36: St := 'Get Disk Free Space';
$3C: St := 'Create File with Handle';
$3E: St := 'Close FILE';
$40: St := 'WriteFile or Device';
$41: St := 'Delete FILE';
$44: St := 'IOCTL';
$3D: St := 'Open File with Handle';
$3F: St := 'Read File or Device';
$42: St := 'Move File pointer';
ELSE
St := 'Unknown DOS Service'
END;
Intr21Desc := St;
END;


FUNCTION DecToHex(Deci: byte): string;

CONST
ConvStr: string[16] = '0123456789ABCDEF';
BEGIN
DecToHex := ConvStr[Deci div 16 + 1] +
ConvStr[Deci mod 16 + 1]
END;


BEGIN
ClrScr;
ExitProc := OldExitProc;
SetIntVec($21,OldInt);
WriteLn('Int # Description');
WriteLn(' # Times');
WriteLn;
FOR I:= 0 TO 255 DO
BEGIN
IF IntCount[I] <> 0 THEN
BEGIN
Write(DecToHex(I),'H');
Write(' ',IntCount[I]:3);
GotoXY(11,WhereY);
WriteLn(Intr21Desc(I))
END
END
END;


PROCEDURE NewInt(AX,BX,CX,DX,SI,
DI,SD,ES,BP: Word); INTERRUPT;

VAR AH: byte;

BEGIN
Sound(1220);Delay(10);NoSound;
AH := Hi(AX);
IntCount[AH] := IntCount[AH]+1;
GoOldInt(OldInt)
END;
{$F-}

{************ Main Program *****************}

VAR I: byte;
F: text;
TestStr: string[40];

BEGIN

ClrScr;

{Install new Exit PROCEDURE}

OldExitProc := ExitProc;
ExitProc := @NewExitProc;

{Install new Interrupt Vector}

GetIntVec($21, OldInt);
SetIntVec($21, @NewInt);

{******** Testing Section ***********}

WriteLn('Starting Testing');Delay(1000);

FillChar(IntCount,SizeOf(IntCount),#0);

FOR I:= 0 TO 255 DO
WriteLn('Testing 1'); {WriteLn's to screens}
{do not use the 21H }
{Interrupt }

Write('TYPE anything TO test keyboard: ');
ReadLn(TestStr);

Writeln('Disk Size ',
DiskSize(3)); {Uses Service 36H}


Assign (F,'TestFile');
Rewrite(f); {Uses Service 3CH,44H}

FOR I:=0 TO 255 DO
WriteLn(F,'This is only A test'); {Service 40H}
WriteLn(F,'This is A test too');
WriteLn(f,'Last test');

Close(f); {Uses Service 3EH,40H}

Assign(F,'TestFile');
Append(f); {Uses Service 3DH,3FH,42H,44H}
Close(F); {Uses Service 3EH,40H}

Assign(F,'TestFile');
Erase(f) {Uses Service 41H}
END.