pic18f computed goto
1) All SFR are not requires banking, so remove any pagesel or bank select instruction.
2) Look for any $-1 like instruction. You need to double the figure. Ex $-1 becomes $-2, $-2 becomes $-4 etc.
3) Look for instruction that modifies PCL like ADDWF PCL, W. Since 18 series address are WORD aligned, you need to add 2 lines before that instruction. CLRF STATUS, C and RLCF WREG, F.
Or use the enhanced feature of 18 series TBLPTRU/H/L. Microchip has an application notes for this.
4) RRF becomes RRCF, RLF becomes RLCF.
5) Am I missing anything else…