Cryptography Reference
In-Depth Information
{
*pptr_l = (USHORT)(carry = (ULONG)av * (ULONG)*bptr_l +
(ULONG)(USHORT)(carry >> BITPERDGT));
}
*pptr_l = (USHORT)(carry >> BITPERDGT);
The loop for summing the inner products
a
i
a
j
.
for (aptr_l = LSDPTR_L (a_l) + 1, csptr_l = LSDPTR_L (p_l) + 3;
aptr_l <= msdptra_l; aptr_l++, csptr_l += 2)
{
carry = 0;
av = *aptr_l;
for (bptr_l = aptr_l + 1, pptr_l = csptr_l; bptr_l <= msdptrb_l;
bptr_l++, pptr_l++)
{
*pptr_l = (USHORT)(carry = (ULONG)av * (ULONG)*bptr_l +
(ULONG)*pptr_l + (ULONG)(USHORT)(carry >> BITPERDGT));
}
*pptr_l = (USHORT)(carry >> BITPERDGT);
}
msdptrc_l = pptr_l;
Then comes multiplication of the intermediate result in
pptr_l
by 2 via shift
operations (see also Section 7.1).
carry = 0;
for (pptr_l = LSDPTR_L (p_l); pptr_l <= msdptrc_l; pptr_l++)
{
*pptr_l = (USHORT)(carry = (((ULONG)*pptr_l) << 1) +
(ULONG)(USHORT)(carry >> BITPERDGT));
}
*pptr_l = (USHORT)(carry >> BITPERDGT);
Now we compute the “main diagonal.”
carry = 0;
for (bptr_l = LSDPTR_L (a_l), pptr_l = LSDPTR_L (p_l);
bptr_l <= msdptrb_l; bptr_l++, pptr_l++)
