Question on Mirror Wall...

Here is another yugioh ruling question:

If it's your opponent's Battle Phase, and he Attacks with a Vorse Raider equipped with an Axe of Despair and , and you activate Mirror Wall to his card...
1) Do you add up the total ATK and divide by 2

OR

2) Do you divide the ORIGINAL ATTACK, then add the effects of equip cards?

Also, what would happen if it is divided a second time????

Please help!

Halve the original ATK of all your opponent's attacking monsters. Pay 2000 Life Points during each of your Standby Phases. If you do not, destroy this card.
You have the original attack then add the equip on and as long as it remains on the field the attack is halved so next turn it halved again.

Thanks! That would make alot of sense.