I note that there is no specific prescription against premarital sex in the Hebrew Scriptures either; that's a Christian addition.
		
		
	 
We are discussing the Bible, which is Christian, but as far as pre-marital sex in the OT, there is Exodus 22:16-17:
"
And if a man entice a maid that is not betrothed, and lie with her, he shall surely endow her to be his wife. If her father utterly refuse to give her unto him, he shall pay money according to the dowry of virgins."
Maid here means "virgin" and so maybe there is a point about non-virgins. Perhaps also I am being too logical and maybe that is true. Because next, I would consider that any non-virgin was once a virgin, even prostitutes. I realize also that there is hypocrisy and at least some of that comes from patriarchal ways of these ancient cultures. So perhaps mentions of daughters given by fathers on a temporary basis were ruined already, compensated, but still taken advantage of to a life of being passed around for compensation since marital prospects (virginity) were ruined. Not sure.
This does seem like a thing to discuss, especially in light of ex-creationist's prostitutes-are-just-a-waste-of-money moral hypothesis about the texts.
So far as the entirety of the bible being legal prescriptions, I don't think that is the case. I am not sure you meant that, but we are discussing the bible as a whole. For example, in Matthew, Jesus is alleged to talk about how if a husband has adultery in his head then that is an equal sin to adultery in the flesh. That isn't really an enforceable thing. Perhaps that is even what you meant, if you were merely distinguishing the OT from the NT. But I was speaking to the texts as a whole in the context of "the bible" as much as we can anyway, since certain persons have chosen certain texts to go together and reject others, depending on the doctrines they are espousing.