rtl addition chain v2

addchain_5inv_rtlv2.py

#                                                                                                                                 ---> up to here is a multiple of 0b110011 = 51 :-)
x_p = 0b11001100110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011001101001110100111101110000011001001101000010000101001100000111000101110000011110000111100111111000011001100110011001100110011001101

pchain = Chain()
pi = pa = 1
for i in range(1, 128):
    pi = pchain.sqr(pi)
    if '01001110100111101110000011001001101000010000101001100000111000101110000011110000111100111111000011001100110011001100110011001101'[127-i] == '1':
        pa = pchain.mul(pa, pi)

#b = '1000100010001000100010001000100010001000100010001000100010001000100010001000100010001000100010001000100010001000100010001000100011010001101'
b = '1000000010000000100000001000000010000000100000001000000010000000100000001000000010000000100000001000000010000000100000001'
assert int(b, 2)*0b110011 == 0b110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011001100110011
pj = pchain.sqrmul(pi, 1, pi)
pk = pchain.sqrmul(pj, 4, pj)
for k in range(1, 122):
    pk = pchain.sqr(pk)
    if b[121-k] == '1':
        pa = pchain.mul(pa, pk)

assert pa == x_p, "\n" + format(pa, '0255b') + "\n" + format(x_p, '0255b')
print(pchain)