def test_signed_add():
A = bitvec('A', 8)
B = bitvec('B', 8)
for adder in (rca, ksa):
S, C = adder(A, B)
# 0 + 0 = 0
assert sadd(S, A, B, 0, 0) == 0
# -64 + -64 = -128
assert sadd(S, A, B, -64, -64) == -128
# -1 + 1 = 0
assert sadd(S, A, B, -1, 1) == 0
# -64 + 64 = 0
assert sadd(S, A, B, -64, 64) == 0
# signed random vectors
for i in range(NVECS):
ra = random.randint(-2**6, 2**6-1) # -64..63
rb = random.randint(-2**6, 2**6) # -64..64
assert sadd(S, A, B, ra, rb) == ra + rb
# 64 + 64, overflow
R = C.vrestrict({A: int2vec(64, 8), B: int2vec(64, 8)})
assert R[7] != R[6]
# -65 + -64, overflow
R = C.vrestrict({A: int2vec(-65, 8), B: int2vec(-64, 8)})
assert R[7] != R[6]
def sadd(S, A, B, aval, bval):
N = len(A)
R = S.vrestrict({A: int2vec(aval, N), B: int2vec(bval, N)})
return R.to_int()