ASMB,A,B,L

      HED ** Small Light Chaser **
* by Tim Riker <Tim@Rikers.org>
      ORG 10B

      CLB,CLE,INB  E=0, B=1

WRITE OTB 1        Write B to S

      LDA DELAY    Get delay in A
      CMA          2's complement A
LOOP  INA,SZA      Increment A, Skip one if =0
      JMP LOOP     Delay some more

ROT   RBL,CLE      rotate left/right 1, Clear E
* FIXME: rotate right still flashes high bit
      SSB,RSS      Skip if high bit set
      JMP WRITE    Rotate another bit

      LDA MAGIC    Load XOR bits for RBL/RBR
      XOR ROT      XOR RBL/RBR
      STA ROT      Store new instruction
      JMP WRITE    Start rotating in the other direction
MAGIC OCT 000100   XOR diff from RBL/RBR

DELAY OCT 017777   amount to delay