Contributor: RAPHAEL VANNEY
{
Here's a unit that will let you open more than the default
maximum number of files (up to about 200, FILES statement
in CONFIG.SYS permitting) :
}
{$o-,f-,r-,s-}
{$IfDef DPMI}
{$c Moveable PreLoad Discardable}
{$EndIf}
Unit ExtHandl ;
Interface
{$IfNDef DPMI}
Procedure DOSRealloc(p : Pointer) ;
{$EndIf}
Implementation
{$IfNDef DPMI}
Procedure DOSRealloc(p : Pointer) ; Assembler ;
{ This procedures changes the size of the memory block allocated to the
program. It proceeds the same way than the SetMemTop procedure of the
Memory unit does. }
Asm
Mov BX, Word Ptr [p] { offset }
Add BX, 0ドルf
Mov CL, 4
ShR BX, CL
Add BX, Word Ptr [p+2] { segment }
Mov AX, PrefixSeg
Sub BX, AX
Mov ES, AX
{ ES contains the program's PSP, BX is the new number of paragraphs
of the memory block. }
Mov AH, 4ドルa { Modify memory allocation }
Int 21ドル
End ;
{$EndIf}
Const
FreeParas = 1024 Div 16 ; { We're going to make sure DOS }
{ still has some RAM }
Reallocating = 1 ;
TPLacksRAM = 2 ;
GettingHandles = 3 ;
Procedure PrintError(ErrNo : Word ; Location : Word) ;
Begin
WriteLn(ParamStr(0)) ;
WriteLn('ExtHandl : Startup error #', ErrNo, ', location=', Location) ;
WriteLn('MaxAvail=', MaxAvail) ;
Write('[Enter] pour continuer...') ;
ReadLn ;
End ;
Begin
{ This initialisation code makes sure DOS is still able to assume
memory allocation requests that are likely to occur (whether by
Spawno or a "Set Handle Count" request).
This allows the main program to use whatever $m statement it needs. }
Asm
{$IfNDef DPMI}
Mov AH, 48ドル { Allocate memory }
Mov BX, $ffff { More than DOS can give us }
Int 21ドル
Cmp BX, FreeParas { BX contains avail paragraphs }
JNC @DOSHasEnough
{ Let's check that the heap contains more than needed bytes }
Mov AX, Word Ptr [HeapPtr+2]
Add AX, FreeParas
Cmp AX, Word Ptr [HeapEnd+2]
JNC @NotEnoughRAM { Actually, TP hasn't enough }
Sub Word Ptr [HeapEnd+2], FreeParas
Push Word Ptr [HeapEnd+2]
Push Word Ptr [HeapEnd]
Call DOSRealloc
JNC @DOSHasEnough
Push AX
Mov AX, Reallocating
Push AX
Call PrintError
Jmp #DOSHasEnough
@NotEnoughRAM:
XOr AX, AX
Push AX
Mov AX, TPLacksRAM
Push AX
Call PrintError
@DOSHasEnough:
{$EndIf}
{ Augmentation du nombre de handles disponibles }
Mov AH, 67ドル { Extend handles }
Mov BX, 199 { Gi'me 2 hundreds of 'em }
Int 21ドル
JNC @PasDErreur { Si CF=1, erreur }
Push AX
Mov AX, GettingHandles
Push AX
Call PrintError
@PasDErreur:
End ;
End.