hashcat/OpenCL/inc_truecrypt_keyfile.cl

DECLSPEC u32 u8add (const u32 a, const u32 b)
{
  const u32 a1 = (a >>  0) & 0xff;
  const u32 a2 = (a >>  8) & 0xff;
  const u32 a3 = (a >> 16) & 0xff;
  const u32 a4 = (a >> 24) & 0xff;

  const u32 b1 = (b >>  0) & 0xff;
  const u32 b2 = (b >>  8) & 0xff;
  const u32 b3 = (b >> 16) & 0xff;
  const u32 b4 = (b >> 24) & 0xff;

  const u32 r1 = (a1 + b1) & 0xff;
  const u32 r2 = (a2 + b2) & 0xff;
  const u32 r3 = (a3 + b3) & 0xff;
  const u32 r4 = (a4 + b4) & 0xff;

  const u32 r = r1 <<  0
              | r2 <<  8
              | r3 << 16
              | r4 << 24;

  return r;
}