Coding for IIgs 2 - working on screen memory

[lyricalnanoha <lyricalnanoha@usotsuki.hoshinet.org>]

Ouch.  Got wedged trying to pull this off, perhaps I'm interpreting the 
hardware wrong.  Looks like it's trying to write in bank 0 instead of bank 
1.  (I'm using the //e way to access bank 1, according to the docs I have, 
rather than trying to go '816 and do it that way, as I don't yet 
understand 65816 mode.)

The way I *wrote* the code, I meant it to leave ][+ space readable while 
making //e space writable.  (It doesn't seem to have done that.)  Whether 
I .org this high or low, it still gets wedged.  (There's nothing 
IIgs-dependent about the code beyond the C029 thing.)

I'm trying to create a memory environment conducive to plotting pixels in 
320x200x16 mode.  The palette approximates EGA.

-uso.

setty:    lda       $C029
          ora       #$80
          sta       $C029
          bit       $C005
          ldy       #32
@1:       lda       paltab-1, y
          sta       $9E00, y
          sta       $9E20, y
          sta       $9E40, y
          sta       $9E60, y
          sta       $9E80, y
          sta       $9EA0, y
          sta       $9EC0, y
          sta       $9EE0, y
          sta       $9F00, y
          sta       $9F20, y
          sta       $9F40, y
          sta       $9F60, y
          sta       $9F80, y
          sta       $9FA0, y
          sta       $9FC0, y
          sta       $9FE0, y
          dey
          bne       @1
          lda       #$00
          ldy       #$C7
@2:       sta       $9D00, y
          dey
          bne       @2
          bit       $C004
          rts

paltab:   .byte     $00, $00, $0C, $00, $C0, $00, $CC, $00
          .byte     $00, $0C, $0C, $0C, $70, $0C, $CC, $0C
          .byte     $77, $07, $0F, $00, $F0, $00, $FF, $00
          .byte     $00, $0F, $0F, $0F, $F0, $0F, $FF, $0F