@verb #144:"exp_mod" this none this rxdo #55
@program #144:"exp_mod" this none this
":exp_mod(a, n, m) => a^n mod m"
{a, n, m} = args
dn = decode_binary(n, 1)
l = (length(dn) - 1) * 8 + toint(ceil(log(tofloat(dn[1])) / log(2.0)))
p = a
i = 1
while (l > 1)
  l = l - 1
  p = this:mod(this:product(p, p), m)
  i = i * 2
  if (this:bit_set(n, l))
    p = this:mod(this:product(p, a), m)
    i = i + 1
  endif
  $command_utils:suspend_if_needed()
endwhile
return p
"This verb previously owned by manta (#7165), and chowned to $slacker upon dewizarding (Sat Aug 17 14:50:06 2002 MDT)."
"Last modified by Dax (#789) on Sat Aug 17 14:50:06 2002 MDT."
.