- 4,6,7,9 vertical

Tested:

- TO BE TESTED: R8 set on/off (during frame)
- TO BE TESTED: R8 set on/off around frame start
- TO BE TESTED: R8 set on/off during VADJ
- TO BE TESTED: r9 during R8 to see which lines cause a trigger or not (0,1,2,3 etc)

- R6=0 when LC=0 (crtc_r6d.asm)
- R6=0 when LC!=0 (crtc_r6d.asm)
- TO BE TESTED: R6=0 in left/right border
- TO BE TESTED: R6=0 in upper/lower border
- TO BE TESTED: How does From Scratch work if my type 1 shows something different.
- R6=LC (crtc_r6b.asm)
- R6 during VADJ (crtc_r6c.asm)
- R9 change during VADJ (crtc_r5e2.asm) to see if MA is triggered
- R5 and R6 values (crtc_r5.asm)
- When does R5 trigger (crtc_r5b.asm)
- R5 change while active (crtc_r5c.asm)
- R4 change during VADJ (crtc_r5d.asm)
- R9 affects char heights during VADJ (crtc_r5e.asm)
- Plus vertical scroll during VADJ (crtc_r5ep.asm)
- R9 affects char height during VADJ by changing R9 (crtc_r5f.asm)
- R4 trigger point (crtc_r4.asm)
- R4 changing to smaller value (crtc_r4b.asm)
- R7 trigger point (crtc_r7.asm)
- TO BE TESTED: R7 during vadj
- R9 trigger (set larger) (crtc_r9.asm)
- R9 trigger (set smaller) (crtc_r9b.asm)

