How to do this in ASM?

[Kamikaze47]

Can someone tell me how I could write assembly that does the same as the following line would in PBP:

array[index]=my_data.Byte0

assuming that the variables are already declared as follows:

array VAR BYTE[12]
index VAR BYTE
my_data VAR WORD

I was trying to work out an ASM equiv but came up empty.

*edit* Its for a 16F84A