def trunc(x):
if type(x) is types.sfix:
return AdvInteger.Oblivious_Trunc(x.v, x.k, x.f, x.kappa)
elif type(x) is types.sfloat:
v, p, z, s = floatingpoint.FLRound(x, 0)
return types.sfloat(v, p, z, s, x.err)
return x
def FLRound(x, mode):
""" Rounding with floating point output.
*mode*: 0 -> floor, 1 -> ceil, -1 > trunc """
v1, p1, z1, s1, l, k = x.v, x.p, x.z, x.s, x.vlen, x.plen
a = types.sint()
AdvInteger.LTZ(a, p1, k, x.kappa)
b = p1.less_than(-l + 1, k, x.kappa)
v2, inv_2pow_p1 = AdvInteger.Oblivious_Trunc(v1, l, -a * (1 - b) * x.p,
x.kappa, True)
c = AdvInteger.EQZ(v2, l, x.kappa)
if mode == -1:
away_from_zero = 0
mode = x.s
else:
away_from_zero = mode + s1 - 2 * mode * s1
v = v1 - v2 + (1 - c) * inv_2pow_p1 * away_from_zero
d = v.equal(AdvInteger.two_power(l), l + 1, x.kappa)
v = d * AdvInteger.two_power(l - 1) + (1 - d) * v
v = a * ((1 - b) * v +
b * away_from_zero * AdvInteger.two_power(l - 1)) + (1 - a) * v1
s = (1 - b * mode) * s1
z = AdvInteger.or_op(AdvInteger.EQZ(v, l, x.kappa), z1)
v = v * (1 - z)
p = ((p1 + d * a) * (1 - b) + b * away_from_zero * (1 - l)) * (1 - z)
return v, p, z, s