Absolutely.

Example:

DEFINE OSC 20

MyVar VAR BYTE ' Define all variables, etc,,

PORTB = %11110000 ' output logic at power-up
TRISB = 0 ' all outputs

Main: ' Main code starts here.

The very first instructions that execute will be port latch setup (value
to place on any output pin at power-up), followed by TRIS settings.