Broken programs

- [ ] invaders hangs when shoot one:
```
09c0 
lda $e840 ; read VIA PORTB 
and #$20
beq 09c0

00 31 3e e9 00110111 09c0 ad
96529 via < 0 E1
00 31 3e e9 00110111 09c3 29
00 31 3e e9 00110111 09c5 f0
```
- [ ] petpanic hangs reading VIA T1LO and T1LLO in loop