.nolist
#include ti83plus.inc
#DEFINE  ProgStart    $9D95
lfsrseed equ appbackupscreen
#define lfsrtaps %10111001
.list
.org progstart-2
.db t2bytetok,tasmcmp
 bcall(_clrlcdfull)
 ld a,77                ;seed
 ld hl,lfsrseed
 ld (hl),a
Main:
 bcall(_getkey)
 bcall(_clrlcdfull)
 ld a,0
 ld (curcol),a
 ld (currow),a
 call LFSR
 ld h,00
 ld l,a
 bcall(_disphl)
 jp main

LFSR: ; outputs random value in a
 ld hl,lfsrseed
 ld a,(hl)
 bit 0,a
 rrca
 jp z,_
 xor lfsrtaps
_:
 ld (hl),a
 ret