HPAVC/HPAVC CD-ROM.iso/pc/ML_BME1.ZIP/_LIB_/XMS.PAS

Pascal/Delphi Source File | 1996-07-18 | 4.7 KB | 244 lines

{$F+}
{$G+}

Unit XMS;

{
  Extended memory (via XMS) handling routines
  by Maple Leaf, 1996
}

Interface

Type
  EMM_Struct = record
                 Count            : LongInt;
                 SourceHandle     : Word;
                 OffsetIntoSource : LongInt;
                 DestHandle       : Word;
                 OffsetIntoDest   : LongInt;
               end;

Var
  XMS_Driver_Address : Pointer;
  XMS_Installed      : Boolean;
  XMS_Error          : byte;
  XMS_Move           : EMM_Struct;
  XMS_Total,
  XMS_Largest        : word;

Procedure CheckXMSInstall;                           far;
Function  XMSVersion : word;                         far;
Procedure AllocXMS ( Var Handle:word; Size:word );   far;
Procedure FreeXMS ( Handle:Word );                   far;
Procedure LockXMS ( Handle:word; Size:word );        far;
Procedure UnLockXMS ( Handle:word; Size:word );      far;
Procedure MoveXMS ( Var EmmStruc:EMM_Struct );       far;
Procedure LocalEnableA20;                            far;
Procedure LocalDisableA20;                           far;
Procedure CopyToXMS    ( Var Source; Handle:Word; Offs:LongInt; Count:LongInt ); far;
Procedure CopyFromXMS  ( Handle:Word; Offs:LongInt; Var Dest; Count:LongInt ); far;
Procedure CopyXMStoXMS ( SHandle:Word; SOffs:LongInt; DHandle:Word; DOffs:LongInt; Count:LongInt ); far;
Procedure QueryXMS;                                  far;
Function  CountXMS : Word;                           far;

Implementation

Procedure CheckXMSInstall;assembler;
asm
  push es
  mov ax,4300h
  int 2fh
  cmp al,80h
  je @Inst
  mov byte ptr XMS_Installed,0
  jmp @Outta
@Inst:
  mov byte ptr XMS_Installed,1
  { Get driver address }
  mov ax,4310h
  int 2fh
  mov word ptr XMS_Driver_Address,bx
  mov word ptr XMS_Driver_Address[2],es
@Outta:
  pop es
end;

Function XMSVersion;Assembler;
asm
  mov ah,0
  call dword ptr XMS_Driver_Address
  { returns in AX version }
end;

Procedure AllocXMS;Assembler;
asm
  mov dx,Size
  mov ah,9
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  push bx
  les bx,dword ptr Handle
  mov word ptr es:[bx],dx
  pop bx
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure QueryXMS;Assembler;
asm
  mov ah,8
  xor bx,bx
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov word ptr XMS_Total,dx
  mov word ptr XMS_Largest,ax
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure FreeXMS;Assembler;
asm
  mov ah,10
  mov dx,Handle
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure LockXMS;Assembler;
asm
  mov ah,12
  mov dx,Handle
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure UnLockXMS;Assembler;
asm
  mov ah,13
  mov dx,Handle
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure MoveXMS;Assembler;
asm
  push ds
  mov ah,11
  lds si,EmmStruc
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
  pop ds
end;

Procedure LocalEnableA20;Assembler;
asm
  mov ah,5
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure LocalDisableA20;Assembler;
asm
  mov ah,6
  call dword ptr XMS_Driver_Address
  cmp ax,1
  jne @Failure
  mov XMS_Error,0
  jmp @Outta
@Failure:
  mov XMS_Error,bl
@Outta:
end;

Procedure CopyToXMS;
Var P:Pointer;
begin
  P:=@Source;
  XMS_Move.Count:=Count;
  XMS_Move.SourceHandle:=0;
  Move(p,XMS_Move.OffsetIntoSource,4);
  XMS_Move.DestHandle:=Handle;
  XMS_Move.OffsetIntoDest:=Offs;
  MoveXMS(XMS_Move);
end;

Procedure CopyFromXMS;
Var P:Pointer;
begin
  P:=@Dest;
  XMS_Move.Count:=Count;
  XMS_Move.SourceHandle:=Handle;
  XMS_Move.OffsetIntoSource:=Offs;
  XMS_Move.DestHandle:=0;
  Move(p,XMS_Move.OffsetIntoDest,4);
  MoveXMS(XMS_Move);
end;

Procedure CopyXMStoXMS;
begin
  XMS_Move.Count:=Count;
  XMS_Move.SourceHandle:=SHandle;
  XMS_Move.OffsetIntoSource:=SOffs;
  XMS_Move.DestHandle:=DHandle;
  XMS_Move.OffsetIntoDest:=DOffs;
  MoveXMS(XMS_Move);
end;

Function  CountXMS : Word;
var k,hand:word;
begin
  k:=1; XMS_Error:=0;
  AllocXMS(hand,k);
  while XMS_Error=0 do begin
    FreeXMS(hand);
    inc(k);
    AllocXMS(hand,k);
  end;
  dec(k);
  CountXMS:=k;
end;

begin
  XMS_Driver_Address:=Nil;
  XMS_Installed:=False;
  CheckXMSInstall;
end.