cpu/alu.ml


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open Netlist_gen

let fulladder a b c =
       let s = a ^^ b ^^ c in
       let r = (a ^& b) ^| ((a ^^ b) ^& c) in
       s, r

let rec nadder n a b c_in =
    if n = 1 then fulladder a b c_in
    else 
        let s_n, c_n1 = fulladder (a ** 0) (b ** 0) c_in in
        let s_n1, c_out = nadder (n-1) (a % (1, n-1)) (b % (1, n-1)) c_n1 in
        s_n ++ s_n1, c_out

let nadder_nocarry n a b =
    let a, b = nadder n a b (const "0") in
    ignore b a

let rec rep n k =
    if n = 1 then k
    else
        let s = rep (n/2) k in
        if n mod 2 = 0 then s ++ s else s ++ s ++ k

let rec sign_extend n_a n_dest a =
    a ++ rep (n_dest - n_a) (a ** (n_a - 1))

let rec eq_c n v c = (* v is a value, c is a constant *)
    if n = 1 then
        if c = 1 then v else not v
    else
        (eq_c 1 (v ** 0) (c mod 2)) ^& (eq_c (n-1) (v % (1, n-1)) (c/2))