VGA_CRTC_H_BLANK_START
vga_wcrt(regbase, VGA_CRTC_H_BLANK_START, var->xres / 8);
par->crtc[VGA_CRTC_H_BLANK_START] = ((xres + right) >> 3) - 1;
write3X4(par, VGA_CRTC_H_BLANK_START, hblankstart & 0xFF);
par->crtc[VGA_CRTC_H_BLANK_START] = xres - 1;