VGA_CRTC_OVERFLOW
wreg_crt(cirrus, VGA_CRTC_OVERFLOW, tmp);
outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
vga_wcrt(regbase, VGA_CRTC_OVERFLOW, tmp);
par->crtc[VGA_CRTC_OVERFLOW] = r7;
write3X4(par, VGA_CRTC_OVERFLOW, tmp);
par->crtc[VGA_CRTC_OVERFLOW] = r7;
vga_io_wcrt(VGA_CRTC_OVERFLOW, par->vga_state.Overflow | 0x84);