Module limb

Unsigned multi-precision integer arithmetic.

Limbs ordered least-significant-limb to most-significant-limb. The bits limbs use the native endianness.

Enums

• AllowZero
• LimbMask

Constants

• LIMB_BITS
• LIMB_BYTES

Functions

• big_endian_from_limbs
• fold_5_bit_windows
  Processes limbs as a sequence of 5-bit windows, folding the windows from most significant to least significant and returning the accumulated result. The first window will be mapped by init to produce the initial value for the accumulator. Then f will be called to fold the accumulator and the next window until all windows are processed. When the input’s bit length isn’t divisible by 5, the window passed to init will be partial; all windows passed to fold will be full.
• limbs_are_even_constant_time
• limbs_are_zero_constant_time
• limbs_equal_limb_constant_time
• limbs_equal_limbs_consttime
• limbs_less_than_limb_constant_time
• limbs_less_than_limbs_consttime
• limbs_less_than_limbs_vartime
• limbs_minimal_bits
  Returns the number of bits in a.
• limbs_reduce_once_constant_time
  Equivalent to if (r >= m) { r -= m; }
• parse_big_endian_and_pad_consttime
  Parses input into result, padding result with zeros to its length. This attempts to be constant-time with respect to the value but not with respect to the length; it is assumed that the length is public knowledge.
• parse_big_endian_in_range_and_pad_consttime
  Parses input into result, verifies that the value is less than max_exclusive, and pads result with zeros to its length. If allow_zero is not AllowZero::Yes, zero values are rejected.
• parse_big_endian_in_range_partially_reduced_and_pad_consttime
  Parses input into result, reducing it via conditional subtraction (mod m). Assuming 2**((self.num_limbs * LIMB_BITS) - 1) < m and m < 2**(self.num_limbs * LIMB_BITS), the value will be reduced mod m in constant time so that the result is in the range [0, m) if allow_zero is AllowZero::Yes, or [1, m) if allow_zero is AllowZero::No. result is padded with zeros to its length.

Type Aliases

• Limb
• Window