Lo-res/Double lo-res (was: Wacky Game idea)

[John Le Febvre <john@klatch.demon.co.uk>]

I was looking to write some routines to do double lo-res graphics from 
Applesoft (mainly to get myself back into 6502 programming!).  Anyway,
whilst looking at the routines from the II+ autostart ROM listings, I
decided that all that was needed was to re-write the GBASCALC routine
to see if the horizontal position byte was odd or even and choose page2
or page1 accordingly.

Anyway, I don't know if this would work but whilst looking at the 
listing I found some code which I think is redundant and was
curious to know if anyone agreed with me (or if it was well known).

This is a snippet from the listing

GBASCALC  PHA
          LSR A
          AND #$03
          ORA #$04
          STA GBASH
          PLA
          AND #$18
          BCC GBCALC
          ADC #$7F
GBCALC    STA GBASL
          ASL A
          ASL A
          ORA GBASL
          STA GBASL
          RTS
          LDA COLOR
          CLC
          ADC #$03
SETCOL    AND #$0F
          ...