vreg
From ArchaicPixels: HuC and PCEAS Documentation
vreg(char idx);
vreg(char idx, int val);
This function gives you direct access to the video
processor (VDC) registers. The first form of this function
is used to just select a VDC register (for custom accesses),
and the second is used to set the value of a register
(it also selects this register).
