def _pow_mod(space, iv, iw, iz):
from rpython.rlib.rarithmetic import mulmod
if iw <= 0:
if iw == 0:
return 1 % iz # != 1, for iz == 1 or iz < 0
raise oefmt(
space.w_TypeError,
"pow() 2nd argument cannot be negative when 3rd "
"argument specified")
if iz < 0:
try:
iz = ovfcheck(-iz)
except OverflowError:
raise
iz_negative = True
else:
iz_negative = False
temp = iv
ix = 1
while True:
if iw & 1:
ix = mulmod(ix, temp, iz)
iw >>= 1 # Shift exponent down by 1 bit
if iw == 0:
break
temp = mulmod(temp, temp, iz)
if iz_negative and ix > 0:
ix -= iz
return ix
def int_mulmod(space, a, b, c):
return space.newint(mulmod(a, b, c))
def func(a, b, c):
return mulmod(a, b, c)