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-rw-r--r--cpu/alu.ml17
1 files changed, 17 insertions, 0 deletions
diff --git a/cpu/alu.ml b/cpu/alu.ml
index 0a0c00f..cf33cd2 100644
--- a/cpu/alu.ml
+++ b/cpu/alu.ml
@@ -12,5 +12,22 @@ let rec nadder n a b c_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))