def call(b, e, m):
with o = 1:
with bit = 2 ^ 255:
while gt(bit, 0):
# A touch of loop unrolling for 20% efficiency gain
o = mulmod(mulmod(o, o, m), b ^ !(!(e & bit)), m)
o = mulmod(mulmod(o, o, m), b ^ !(!(e & div(bit, 2))), m)
o = mulmod(mulmod(o, o, m), b ^ !(!(e & div(bit, 4))), m)
o = mulmod(mulmod(o, o, m), b ^ !(!(e & div(bit, 8))), m)
bit = div(bit, 16)
return(o)