(*
KELD R. HANSEN

> I need to *simulate* something like:
> {$M 16384,0,0}               {reduce heap}
> Exec('c:\myprgm.exe','');    {run myprgm.exe}
> {$M 16384,110000,110000}     {restore heap}

EXECUTE shrinks your programs memory allocation to the smallest possible value,
then runs the program and then expands it back up again. Works in TP 6.0 and
7.0!
*)

USES
  DOS;

TYPE
  STR127 = STRING[127];

PROCEDURE ReallocateMemory(P : POINTER); ASSEMBLER;
ASM
  MOV  AX, PrefixSeg
  MOV  ES, AX
  MOV  BX, WORD PTR P+2
  CMP  WORD PTR P,0
  JE   @OK
  INC  BX

 @OK:
  SUB  BX, AX
  MOV  AH, 4Ah
  INT  21h
  JC   @X
  LES  DI, P
  MOV  WORD PTR HeapEnd,DI
  MOV  WORD PTR HeapEnd+2,ES

 @X:
END;

FUNCTION EXECUTE(Name : PathStr ; Tail : STR127) : WORD; ASSEMBLER;
ASM
  {$IFDEF CPU386}
  DB      66h
  PUSH    WORD PTR HeapEnd
  DB      66h
  PUSH    WORD PTR Name
  DB      66h
  PUSH    WORD PTR Tail
  DB      66h
  PUSH    WORD PTR HeapPtr
  {$ELSE}
  PUSH    WORD PTR HeapEnd+2
  PUSH    WORD PTR HeapEnd
  PUSH    WORD PTR Name+2
  PUSH    WORD PTR Name
  PUSH    WORD PTR Tail+2
  PUSH    WORD PTR Tail
  PUSH    WORD PTR HeapPtr+2
  PUSH    WORD PTR HeapPtr
  {$ENDIF}
  CALL ReallocateMemory
  CALL SwapVectors
  CALL DOS.EXEC
  CALL SwapVectors
  CALL ReallocateMemory
  MOV  AX, DosError
  OR   AX, AX
  JNZ  @OUT
  MOV  AH, 4Dh
  INT  21h

 @OUT:
END;