- mov ax, [di] ; grab vertex Y
- add ax, [si] ; add velocity Y
- jl .yout
- cmp ax, 200-SHADOW_OFFS
- jge .yout
- jmp .skip_yflip
-.yout:
- sub ax, [si] ; revert to previous Y
- neg word [si] ; negate velocity Y
-.skip_yflip:
- mov [di], ax ; update vertex Y