Category : Files from Magazines
Archive   : ISSUE-38.ZIP
Filename : 86WRLD38.FIG

{ listing 1 - corrected Exec for Turbo Pascal }

{--------------------------- Exec ----------------------------}
{ execute 'Command' as if it was typed at the A> prompt }
{ requires Getenvironment function from Micro C. 32 }
{-------------------------------------------------------------}
FUNCTION Exec (Command : string128) : INTEGER;

CONST
SSSave : INTEGER = 0;
SPSave : INTEGER = 0;
RetAX : INTEGER = 0;
RetFlags : INTEGER = 0;

TYPE
ExecPacketRec = RECORD
EnvironmentSeg : INTEGER;
CommandPtr,
FCB1,
FCB2 : ^CHAR;
end; { ExecPacketRec }

VAR ComFile : String20;
ExecPack : ExecPacketRec;

begin
ComFile := GetEnvironment('COMSPEC')+chr(0);{ execute command.com }
IF (length(command) > 0) THEN { sending it this line }
Insert ('/c ',Command,1); { 'c' switch means 'do this' }
command[length(command)+1] := ^M;

ExecPack.EnvironmentSeg := $0000; { use parent's environment }
ExecPack.CommandPtr := Ptr(seg(Command),ofs(Command));
ExecPack.FCB1 := Ptr(0,0);
ExecPack.FCB2 := Ptr(0,0);

{ START OF MODIFIED AREA }
inline($06/$1E/$55/$9C/ { push es, ds, bp, flags }
$8C/$D0/$8E/$D8/ { mov ax,ss mov ds,ax (seg(ComFile)) }
$BA/ComFile/ { mov dx,offset ComFile[0] }
$01/$EA/$42/ { add dx,bp inc dx }
$8E/$C0/ { mov es,ax (seg(ExecPack)) }
$BB/ExecPack/ { mov bx,offset ExecPack }
$01/$EB/ { add bx,bp }
$B8/$00/$4B/ { mov ax,4B00h }
$2E/$8C/$16/SSSave/ { mov cs:[SSSave],ss <<-}
$2E/$89/$26/SPSave/ { mov cs:[SPSave],sp <<-}
$CD/$21/ { int 21h }
$2E/$8E/$16/SSSave/ { mov ss,cs:[SSSave] <<-}
$2E/$8B/$26/SPSave/ { mov sp,cs:[SPSave] <<-}
$2E/$A3/RetAX/ { mov cs:[RetAX],ax }
$9C/$58/ { pushf pop ax }
$2E/$A3/RetFlags/ { mov cs:[RetFlags],ax }
$9D/$5D/$1F/$07); { pop flags, bp, ds, es }

IF ((RetFlags and CARRY) = 0) THEN
Exec := 0
ELSE
Exec := RetAX;
{ END OF MODIFIED AREA }
end; { Exec }