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open Base
open Hardcaml
include Add_intf
module Make_gen (B : Gen) = struct
module B = B
open B
module Add_result = struct
type t =
{ carry : B.bit
; sum : B.bit
}
[@@deriving sexp_of]
end
type add_result = Add_result.t =
{ carry : B.bit
; sum : B.bit
}
let full_adder x y z : Add_result.t =
{ sum = x ^: y ^: z; carry = x &: y |: (x &: z) |: (y &: z) }
;;
let half_adder x y : Add_result.t = { sum = x ^: y; carry = x &: y }
module Subtract_result = struct
type t =
{ borrow : B.bit
; sub : B.bit
}
[@@deriving sexp_of]
end
type subtract_result = Subtract_result.t =
{ borrow : B.bit
; sub : B.bit
}
let subtractor x y z : Subtract_result.t =
{ sub = x ^: y ^: z; borrow = ~:x &: (y |: z) |: (x &: y &: z) }
;;
let ripple_carry_adder x y ~carry_in_bit =
let c, s =
List.fold2_exn
(List.rev (bits_msb x))
(List.rev (bits_msb y))
~init:(carry_in_bit, [])
~f:(fun (carry_in, sum_bits) x y ->
let { Add_result.carry; sum } = full_adder x y carry_in in
carry, sum :: sum_bits)
in
concat_msb (c :: s)
;;
end
module Make (B : Comb.S) = Make_gen (struct
include B
type bit = t [@@deriving sexp_of]
end)