unit1.pas

在delphi中实现windows核心编程.原书光盘代码核心编程.原书光盘代码

unit Unit1;

interface

uses WINPROCS,SysUtils,Dialogs;
  procedure SetSegment(DSegment,DOffset:longint);export;
  function ReadPhysMemory(PhAddr:Pointer;ReadSize:longint):boolean;export;
  function WritePhysMemory(PhAddr:Pointer;ReadSize:longint):boolean;export;

implementation

var
  Segment,Offset:word;

function MapPhysicalToLinear(dwPhysical,dwLength:longint):longint;
label fine_return;
var
   dwLinear:longint;
begin
   dwLinear := 0;
   asm
           push    di
           push    si
           mov     bx, WORD PTR [dwPhysical+2]
           mov     cx, WORD PTR [dwPhysical]
           mov     si, WORD PTR [dwLength+2]
           mov     di, WORD PTR [dwLength]
           mov     ax, 800h
           int     31h
           jnc     fine_return
           xor     bx, bx
           mov     cx, bx
   fine_return:
           mov     WORD PTR [dwLinear+2], bx
           mov     WORD PTR [dwLinear], cx
           pop     si
           pop     di
   end;
   result:=dwLinear;
end;

function DPMISetSelectorLimit (selector:word;dwLimit:longint):boolean;
label success;
var
  r:boolean;
begin
   r:=true;
   asm
      pusha
      mov  ax, 0008h
      mov  bx, selector
      mov  cx, word ptr [dwLimit+2]
      mov  dx, word ptr [dwLimit]
      int  31h
      jnc  success
      mov  r, 0  
    success:
      popa
   end;
   result:=r;
end;

function ReadPhysMemory(PhAddr:Pointer;ReadSize:longint):boolean;
var
  codeSelector,tempSelector:word;
  Linear:longint;
  fMemoryPointer :Pointer;
begin
   result:=false;
   if ReadSize=0 then exit;
   {分配新的选择器}
   asm
     push ax
     mov ax,cs
     mov CodeSelector,ax
     pop ax
   end;

   tempSelector:=AllocSelector(codeSelector);
   if tempSelector=0 then exit;
   if PrestoChangoSelector (codeSelector, tempSelector)<>0 then
   begin
     {设置选择器的基地址}
     Linear:=MapPhysicalToLinear(Segment*$10000+Offset,ReadSize);
     SetSelectorBase(tempSelector, Linear);
     DPMISetSelectorLimit(tempSelector, ReadSize-1);
     fMemoryPointer:=Ptr(tempSelector,0);
     {拷贝内存块数据}
     move(fMemoryPointer^,Phaddr^,ReadSize);
     DPMISetSelectorLimit(tempSelector, 0);
     Result:=true;
   end; 
   FreeSelector(tempSelector);
end;

function WritePhysMemory(PhAddr:Pointer;ReadSize:longint):boolean;
var
  codeSelector,tempSelector:word;
  Linear:longint;
  fMemoryPointer :Pointer;
begin
   result:=false;
   if ReadSize=0 then exit;
   {分配新的选择器}
   asm
     push ax
     mov ax,cs
     mov CodeSelector,ax
     pop ax
   end;

   tempSelector:=AllocSelector(codeSelector);
   if tempSelector=0 then exit;
   if PrestoChangoSelector (codeSelector, tempSelector)<>0 then
   begin
     {设置选择器的基地址}
     Linear:=MapPhysicalToLinear(Segment*$10000+Offset,ReadSize);
     SetSelectorBase(tempSelector, Linear);
     DPMISetSelectorLimit(tempSelector, ReadSize-1);
     fMemoryPointer:=Ptr(tempSelector,0);
     {拷贝内存块数据}
     move(Phaddr^,fMemoryPointer^,ReadSize);
     DPMISetSelectorLimit(tempSelector, 0);
     Result:=true;
   end;
   FreeSelector(tempSelector);
end;

{设置段选择符}
procedure SetSegment(DSegment,DOffset:longint);
begin
  Segment:=DSegment;
  Offset:=DOffset;
end;

end.