What is the role of left/right margin in the sync lines? Because I looked at the few examples I gathered and there are other values written...
I mean the example found in one of the exos manuals: ; PIXEL for 256 lines (4 color)
DB 256-256,pixel+c4+vres,14,14+32
DW screen,0
DB 0,1,2,3,4,5,6,7
;blank for 5 lines ; bottom margin
DB 256-5,lpixel,63,0
DB 0,0,0,0,0,0,0,0,0,0,0,0
;black for 10 lines ; start of vertical blanking period
DB 256-10,lpixel,4,63
DB 0,0,0,0,0,0,0,0,0,0,0,0
;start vsync (4 lines) ; vertical sync pulse
DB 256-4,vblank,4,63
DB 0,0,0,0,0,0,0,0,0,0,0,0
;end vsync (1 line) ; finish vertical sync pulse
DB 256-1,vblank,63,4
DB 0,0,0,0,0,0,0,0,0,0,0,0
;black for 30 lines
DB 256-30,lpixel,4,63 ; rest of vertical blanking period
DB 0,0,0,0,0,0,0,0,0,0,0,0
;blank for 6 lines ; top margin with reload to satart again
DB 256-6,reload+lpixel,63,0
DB 0,0,0,0,0,0,0,0,0,0,0,0