private static void LONG2BYTES(uint l, PositionalBuffer pb)
{
pb.Write8((byte)(l >> 24), 0);
pb.Write8((byte)(l >> 16), 1);
pb.Write8((byte)(l >> 8), 2);
pb.Write8((byte)(l), 3);
}
public static void CalculateChecksum(PositionalBuffer pb)
{
uint sum1, sum2;
{
uint i;
uint c1, k1, k2;
uint t1, t2, t3, t4;
uint t5, t6;
t1 = CHECKSUM_STARTVALUE;
t2 = CHECKSUM_STARTVALUE;
t3 = CHECKSUM_STARTVALUE;
t4 = CHECKSUM_STARTVALUE;
t5 = CHECKSUM_STARTVALUE;
t6 = CHECKSUM_STARTVALUE;
pb.offset = CHECKSUM_START;
for (i = 0; i < CHECKSUM_LENGTH; i += 4)
{
c1 = BYTES2LONG(pb);
k1 = t6 + c1;
if (k1 < t6)
{
t4++;
}
t6 = k1;
t3 ^= c1;
k2 = c1 & 0x1f;
k1 = ROL(c1, (int)k2);
t5 += k1;
if (c1 < t2)
{
t2 ^= k1;
}
else
{
t2 ^= t6 ^ c1;
}
t1 += c1 ^ t5;
pb.AddOffset(4);
}
sum1 = t6 ^ t4 ^ t3;
sum2 = t5 ^ t2 ^ t1;
}
pb.offset = 16;
LONG2BYTES(sum1, pb);
pb.offset = 20;
LONG2BYTES(sum2, pb);
}
private static uint BYTES2LONG(PositionalBuffer pb)
{
return((uint)((pb.Read8(0) << 24) | ((pb.Read8(1) & 0xff) << 16) | ((pb.Read8(2) & 0xff) << 8) | ((pb.Read8(3) & 0xff))));
}
public void TransferFrom(PositionalBuffer buf)
{
this.rom = buf.rom;
}