import vsc


# Random stimuli model class
@vsc.randobj
class constraints():
    def __init__(self):
        self.key = vsc.rand_bit_t(128)
        self.data = vsc.rand_bit_t(128)

    @vsc.constraint
    def c(self):
        self.data >= 0 and self.data <= 2**128-1
        vsc.dist(self.key, [
            vsc.weight(0,  15),
            vsc.weight((1,2**128-2), 70),
            vsc.weight((2**128-1), 15)])


# Stimuli covergroup
@vsc.covergroup
class covergroup():
    def __init__(self, name="bla"):
        self.options.name = name
        self.with_sample(
            mode = vsc.bit_t(1),
            key = vsc.bit_t(128)
        )

        self.enc = vsc.coverpoint(self.mode, bins=dict(
            enc = vsc.bin(0)))

        self.dec = vsc.coverpoint(self.mode, bins=dict(
            dec = vsc.bin(1)))

        self.key0 = vsc.coverpoint(self.key, bins=dict(
            key0 = vsc.bin(0)))

        self.keyF = vsc.coverpoint(self.key, bins=dict(
            keyF = vsc.bin(2**128-1)))

        self.encXkey0 = vsc.cross([self.enc, self.key0])
        self.encXkeyF = vsc.cross([self.enc, self.keyF])

        self.decXkey0 = vsc.cross([self.dec, self.key0])
        self.decXkeyF = vsc.cross([self.dec, self.keyF])