romutils.pas

一个不出名的GBA模拟器

//////////////////////////////////////////////////////////////////////
unit romUtils; ///////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////
interface ////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////

uses
  Windows, Classes, SysUtils, ShellAPI, Math, nexus, console,
  AddressSpace;

//////////////////////////////////////////////////////////////////////

var
  headerIndex: integer;

//////////////////////////////////////////////////////////////////////

function crc32(crc: longword; buf: PByteArray; len: longword): longword;
procedure LoadResourceFile(filename: string; var buffer; bufferSize: integer);
function RoundUpToPow2(num: uint32): uint32;
procedure PatchHeader;
function CrcROM: uint32;

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implementation ///////////////////////////////////////////////////////
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const
  crcTable: array[0..255] of longword = (
    $00000000, $77073096, $ee0e612c, $990951ba, $076dc419,
    $706af48f, $e963a535, $9e6495a3, $0edb8832, $79dcb8a4,
    $e0d5e91e, $97d2d988, $09b64c2b, $7eb17cbd, $e7b82d07,
    $90bf1d91, $1db71064, $6ab020f2, $f3b97148, $84be41de,
    $1adad47d, $6ddde4eb, $f4d4b551, $83d385c7, $136c9856,
    $646ba8c0, $fd62f97a, $8a65c9ec, $14015c4f, $63066cd9,
    $fa0f3d63, $8d080df5, $3b6e20c8, $4c69105e, $d56041e4,
    $a2677172, $3c03e4d1, $4b04d447, $d20d85fd, $a50ab56b,
    $35b5a8fa, $42b2986c, $dbbbc9d6, $acbcf940, $32d86ce3,
    $45df5c75, $dcd60dcf, $abd13d59, $26d930ac, $51de003a,
    $c8d75180, $bfd06116, $21b4f4b5, $56b3c423, $cfba9599,
    $b8bda50f, $2802b89e, $5f058808, $c60cd9b2, $b10be924,
    $2f6f7c87, $58684c11, $c1611dab, $b6662d3d, $76dc4190,
    $01db7106, $98d220bc, $efd5102a, $71b18589, $06b6b51f,
    $9fbfe4a5, $e8b8d433, $7807c9a2, $0f00f934, $9609a88e,
    $e10e9818, $7f6a0dbb, $086d3d2d, $91646c97, $e6635c01,
    $6b6b51f4, $1c6c6162, $856530d8, $f262004e, $6c0695ed,
    $1b01a57b, $8208f4c1, $f50fc457, $65b0d9c6, $12b7e950,
    $8bbeb8ea, $fcb9887c, $62dd1ddf, $15da2d49, $8cd37cf3,
    $fbd44c65, $4db26158, $3ab551ce, $a3bc0074, $d4bb30e2,
    $4adfa541, $3dd895d7, $a4d1c46d, $d3d6f4fb, $4369e96a,
    $346ed9fc, $ad678846, $da60b8d0, $44042d73, $33031de5,
    $aa0a4c5f, $dd0d7cc9, $5005713c, $270241aa, $be0b1010,
    $c90c2086, $5768b525, $206f85b3, $b966d409, $ce61e49f,
    $5edef90e, $29d9c998, $b0d09822, $c7d7a8b4, $59b33d17,
    $2eb40d81, $b7bd5c3b, $c0ba6cad, $edb88320, $9abfb3b6,
    $03b6e20c, $74b1d29a, $ead54739, $9dd277af, $04db2615,
    $73dc1683, $e3630b12, $94643b84, $0d6d6a3e, $7a6a5aa8,
    $e40ecf0b, $9309ff9d, $0a00ae27, $7d079eb1, $f00f9344,
    $8708a3d2, $1e01f268, $6906c2fe, $f762575d, $806567cb,
    $196c3671, $6e6b06e7, $fed41b76, $89d32be0, $10da7a5a,
    $67dd4acc, $f9b9df6f, $8ebeeff9, $17b7be43, $60b08ed5,
    $d6d6a3e8, $a1d1937e, $38d8c2c4, $4fdff252, $d1bb67f1,
    $a6bc5767, $3fb506dd, $48b2364b, $d80d2bda, $af0a1b4c,
    $36034af6, $41047a60, $df60efc3, $a867df55, $316e8eef,
    $4669be79, $cb61b38c, $bc66831a, $256fd2a0, $5268e236,
    $cc0c7795, $bb0b4703, $220216b9, $5505262f, $c5ba3bbe,
    $b2bd0b28, $2bb45a92, $5cb36a04, $c2d7ffa7, $b5d0cf31,
    $2cd99e8b, $5bdeae1d, $9b64c2b0, $ec63f226, $756aa39c,
    $026d930a, $9c0906a9, $eb0e363f, $72076785, $05005713,
    $95bf4a82, $e2b87a14, $7bb12bae, $0cb61b38, $92d28e9b,
    $e5d5be0d, $7cdcefb7, $0bdbdf21, $86d3d2d4, $f1d4e242,
    $68ddb3f8, $1fda836e, $81be16cd, $f6b9265b, $6fb077e1,
    $18b74777, $88085ae6, $ff0f6a70, $66063bca, $11010b5c,
    $8f659eff, $f862ae69, $616bffd3, $166ccf45, $a00ae278,
    $d70dd2ee, $4e048354, $3903b3c2, $a7672661, $d06016f7,
    $4969474d, $3e6e77db, $aed16a4a, $d9d65adc, $40df0b66,
    $37d83bf0, $a9bcae53, $debb9ec5, $47b2cf7f, $30b5ffe9,
    $bdbdf21c, $cabac28a, $53b39330, $24b4a3a6, $bad03605,
    $cdd70693, $54de5729, $23d967bf, $b3667a2e, $c4614ab8,
    $5d681b02, $2a6f2b94, $b40bbe37, $c30c8ea1, $5a05df1b,
    $2d02ef8d);

//////////////////////////////////////////////////////////////////////

function crc32(crc: longword; buf: PByteArray; len: longword): longword;
var
  i: longword;
begin
  if buf <> nil then begin
    crc := crc xor $FFFFFFFF;
    for i := 0 to len-1 do
      crc := crcTable[(crc xor buf[i]) and $FF] xor (crc shr 8);
    Result := crc xor $FFFFFFFF;
  end else
    Result := 0;
end;

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procedure LoadResourceFile(filename: string; var buffer; bufferSize: integer);
var
  HResInfo: integer;
  HGlobal: THandle;
  ext: string;
begin
  ext := ExtractFileExt(filename);
  Delete(filename, Length(filename)-Length(ext)+1, Length(ext));
  Delete(ext, 1, 1);

  HResInfo := FindResource(HInstance, PChar(filename), PChar(ext));
  HGlobal := LoadResource(HInstance, HResInfo);
  if HGlobal = 0 then
     raise EResNotFound.Create('Can''t load resource: ' + filename + '.' + ext);

  Move(LockResource(HGlobal)^, buffer, Min(SizeOfResource(HInstance, HResInfo), bufferSize));

  UnlockResource(HGlobal);
  FreeResource(HGlobal);
end;

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function RoundUpToPow2(num: uint32): uint32;
begin
  Result := 1;
  while Result < num do Result := Result shl 1;
end;

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// Looks at the game code and compares it to the multiboot signature
{function IsMultiboot(header: PAGBROMHeader): boolean;
const
  MB_SIG = $4D422020; // 'MB  '
begin
  Result := uint32(@(header^.code[0])) = MB_SIG;
end;}

//////////////////////////////////////////////////////////////////////

procedure PatchHeader;
var
  i: integer;
  sum: uint32;
  banks: TvmMemoryLock1;
  b9C, b9E: byte;
begin
  vmLockMemory(banks);
  if (headerIndex >= 0) and (banks.romsize > 255) then begin
    // Copy the logo into place (keeping the 4 chanagable bits)
    b9C := $21 or (banks.rom^[$9C] and $84);
    b9E := $F8 or (banks.rom^[$9E] and $3);
    Move(banks.bios^[headerIndex], banks.rom^[4], $9C);

    // Set the funky bits
    banks.rom^[$9C] := b9C;
    banks.rom^[$9E] := b9E;
    banks.rom^[$B2] := $96;

    // Calculate the checksum
    sum := $19;
    for i := $A0 to $BC do sum := sum + banks.rom^[i];
    banks.rom^[$BD] := -sum;
  end;
  vmUnlockMemory(banks);
end;

//////////////////////////////////////////////////////////////////////

function CrcROM: uint32;
var
  banks: TvmMemoryLock1;
begin
  Result := 0;
  if banks.romSize > $100 then begin
    vmLockMemory(banks);
    Result := crc32(0, @(banks.rom^[$100]), banks.romsize - $100);
    vmUnlockMemory(banks);
  end;
end;

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end.

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