Ðåôåðàò: Ñåìàíòè÷åñêèé àíàëèç ñòðóêòóðû EXE ôàéëà è äèñàññåìáëåð (ñ ïðèìåðàìè è èñõîäíèêàìè), âèðóñîëîãèÿ
---------- include file IO.INC ---- CUT HERE FOR IO.INC -------------
procedure WriteHex(B: byte);
const
Hex: ARRAY [0 .. 15] OF CHAR = '0123456789ABCDEF';
var
i: integer;
begin
for i:= 1 downto 0 do
write(Hex[((B shr (i shl 2)) and $000F)])
end;
procedure WritelnHex(B: byte);
begin
WriteHex(B);
writeln
end;
procedure WriteHexInt(N: integer);
begin
WriteHex(N shr 8);
WriteHex(N and $00FF)
end;
procedure WritelnHexInt(N: integer);
begin
WriteHex(N shr 8);
WritelnHex(N and $00FF)
end;
procedure WriteAddress(N, M: integer);
begin
WriteHexInt(N);
Write(':');
WriteHexInt(M)
end;
procedure HexString(var Str; N: INTEGER);
const
Hex: ARRAY [0 .. 15] OF CHAR = '0123456789ABCDEF';
var
i: byte;
begin
for i:= 0 to Mem[Seg(Str):Ofs(Str)] - 1 do
Mem[Seg(Str):(Ofs(Str)+Mem[Seg(Str):Ofs(Str)]-i)] :=
Ord(Hex[((N shr (i shl 2)) and $000F)])
end;
procedure WriteDouble(High, Low: INTEGER);
type
LongInt = ARRAY [0..3] OF BYTE;
const
Divisors : ARRAY [0..9] OF LongInt = ( ( 0, 0, 0, 1),
( 0, 0, 0, $A),
( 0, 0, 0, $64),
( 0, 0, 3, $E8),
( 0, 0, $27, $10),
( 0, 1, $86, $A0),
( 0, $F, $42, $40),
( 0, $98, $96, $80),
( 5, $F5, $E1, 0),
($3B, $9A, $CA, 0) );
var
i, j : INTEGER;
CharOffset,
Digit : BYTE;
Rep : ARRAY [0..9] OF CHAR;
Number : LongInt absolute Low;
OldNumber : LongInt;
stop : BOOLEAN;
begin
CharOffset := Ord(' ');
OldNumber := Number;
Rep := ' ';
for i:=9 downto 0 do begin
Digit := 0;
Number := OldNumber;
stop := false;
repeat
(* subtract Divisor from TestNumber *)
for j:=0 to 3 do begin
Number[j] := Number[j] - Divisors[i][3-j];
if (Number[j] > OldNumber[j]) AND (j<>3) then
Number[j+1] := number[j+1] - 1;
end;
if (Number[3] <= OldNumber[3]) then begin
Digit := succ(Digit);
CharOffset := Ord('0');
OldNumber := Number
end
else stop := true;
until stop;
Rep[9-i] := Chr(CharOffset+Digit);
end;
Write(Rep)
end;
procedure ComOut(var par);
const
WriteCommand = 1;
var
regs: RECORD
AX, BX, CX, DX, BP, SI, DI, DS, ES, Flags: INTEGER
END;
B : BYTE absolute par;
begin
with Regs do begin
AX := (WriteCommand shl 8) + B;
DX := 0;
Intr($14, Regs);
end
end;
procedure BlockRead (var f: file; var buffer; var n: integer);
const
readfunction = $3F;
var
regs: RECORD
AX, BX, CX, DX, BP, SI, DI, DS, ES, Flags: INTEGER
END;
begin
with Regs do begin
AX := (readfunction shl 8);
BX := MemW[Seg(f):Ofs(f)];
CX := n;
DX := Ofs(buffer);
DS := Seg(buffer);
Intr($21, Regs);
if (Flags and $0001) = 1 then begin
write('I/O Error ');
writeHex(AX shr 8);
writeln (' during BlockRead');
end
else
n := AX
end;
end;
function FileSize (var f: file): INTEGER;
const
seekfunction = $42;
from_begin = 0;
from_current = 1;
from_end = 2;
var
regs: RECORD
AX, BX, CX, DX, BP, SI, DI, DS, ES, Flags: INTEGER
END;
CurrentFilePointer_low,
CurrentFilePointer_high : INTEGER;
begin
with Regs do begin
AX := (seekfunction shl 8) + from_current;
BX := MemW[Seg(f):Ofs(f)]; (* handle ! *)
CX := 0; (* offset-high *)
DX := 0; (* offset-low *)
Intr($21, Regs);
if (Flags and $0001) = 1 then begin
write('I/O Error ');
writeHex(AX shr 8);
writeln (' during FileSize');
end;
CurrentFilePointer_low := AX;
CurrentFilePointer_high := DX;
(* determine file size *)
AX := (seekfunction shl 8) + from_end;
BX := MemW[Seg(f):Ofs(f)]; (* handle ! *)
CX := 0; (* offset-high *)
DX := 0; (* offset-low *)
Intr($21, Regs);
if (Flags and $0001) = 1 then begin
write('I/O Error ');
writeHex(AX shr 8);
writeln (' during FileSize');
end;
FileSize := AX;
(* restore FilePointer *)
AX := (seekfunction shl 8) + from_begin;
BX := MemW[Seg(f):Ofs(f)]; (* handle ! *)
CX := CurrentFilePointer_high;
DX := CurrentFilePointer_low;
Intr($21, Regs);
if (Flags and $0001) = 1 then begin
write('I/O Error ');
writeHex(AX shr 8);
writeln (' during FileSize');
end;
end
end;
procedure BlockWrite (var f: file; var b; var n: integer);
const
writefunction = $40;
var
regs: RECORD
AX, BX, CX, DX, BP, SI, DI, DS, ES, Flags: INTEGER
END;
begin
with Regs do begin
AX := (writefunction shl 8);
BX := MemW[Seg(f):Ofs(f)];
CX := n;
DX := Ofs(b);
DS := Seg(b);
Intr($21, Regs);
if (Flags and $0001) = 1 then begin
write('I/O Error ');
writeHex(AX shr 8);
writeln (' during BlockWrite');
end
end;
end;
procedure Open(var f: file; VAR Name);
const
OpenFunction = $3D;
OpenMode = 128; (* read only *)
var
FName: STRING [255] ABSOLUTE Name;
regs: RECORD
AX, BX, CX, DX, BP, SI, DI, DS, ES, Flags: INTEGER
END;
begin
FName := FName + chr (0);
with Regs do begin
AX := (OpenFunction shl 8) + OpenMode;
DX := Ofs (FName) + 1;
DS := Seg (FName);
Intr($21, Regs);
MemW [Seg (f) : Ofs (f)] := AX;
if (Flags and $0001) = 1 then begin
write('I/O Error ');
writeHex(AX shr 8);
writeln (' during Reset');
end
end
end;
----------- start of source ---- CUT HERE FOR DEB2ASM.PAS -------------
const
blank = ' ';
tab = #9;
comma = ',';
colon = ':';
semicolon = ';';
type
STR4 = STRING[4];
STR5 = STRING[5];
STR6 = STRING[6];
STR12 = STRING[12];
STR18 = STRING[18];
STR80 = STRING[80];
ReferenceTypes = (None, B, W, D, N, F);
ParseTypes = RECORD
Offset : STR4;
HexCode : STR12;
OpCode : STR6;
Operand1,
Operand2 : STR12;
Comment : BYTE; (* position where comment starts *)
TypeOverride : ReferenceTypes
END;
var
f_in, f_out : text[$2000];
Line : STR80;
LineCount,
CharPos : INTEGER;
FileName : STR80;
FileExt : BOOLEAN;
Rep : ARRAY [ReferenceTypes] OF STR5;
ParsedLine : ParseTypes;
(*$I <path>\io.inc *)
(*$I <path>\sort.box *)
const
SymbolTableSize = 2000;
type
TableEntry = RECORD
offset,
reference : INTEGER;
reftype : ReferenceTypes;
position : BYTE
END;
var
SymbolTable,
AuxTable : ARRAY [0 .. SymbolTableSize] OF TableEntry;
Current_SymbolTable_Index,
Symbol_Table_Length,
SortInputIndex,
SortOutputIndex,
SortStatus : INTEGER;
(* TOOLBOX SORT interface *)
procedure Inp;
begin
while SortInputIndex < Symbol_Table_Length do begin
SortRelease(SymbolTable[SortInputIndex]);
SortInputIndex := succ(SortInputIndex)
end;
end;
procedure Outp;
begin
while (NOT SortEOS) AND (SortOutputIndex <= Symbol_Table_Length) do begin
SortReturn(AuxTable[SortOutputIndex]);
SortOutputIndex := succ(SortOutputIndex) ;
end;
end;
function Less;
var
Entry1 : TableEntry absolute X;
Entry2 : TableEntry absolute Y;
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