I’m waiting your next post. ;-)

I’ll give you some information about BSF and BCF:

BSF f,b (Bit Set f, sets the bit ‘b’ in register ‘f’)
BCF f,b (Bit Clear f, clears the bit ‘b’ in register ‘f’)

The STATUS register has two bits (RP1, RP0) that select which bank we can access:
RP1-RP0->Bank
0 0 -> 0
0 1 -> 1
1 0 -> 2
1 1 -> 3

In that code example you pasted, each block of two lines is setting the bank to 0, then 1, then 2. Finally, it’s set back to bank 0.

Hope that makes it clearer. =)

What does exactly instructions BSF and BCF?
I see that it is for selecting banks, do not? but I haven’t found any logic in how you use them.

BCF STATUS,RP0
BCF STATUS,RP1
; first block
BSF STATUS,RP0
BCF STATUS,RP1
;second block
BSF STATUS,RP1
BCF STATUS,RP0
;third block
BCF STATUS,RP0
BCF STATUS,RP1

Regards.