VGA_CRTC_CURSOR_START
s = vga_get_crtc(VGA_REG_BASE, VGA_CRTC_CURSOR_START) & 0xC0;
vga_set_crtc(VGA_REG_BASE, VGA_CRTC_CURSOR_START, s);
REG_WRITE1(sc, VGA_CRTC_ADDRESS, VGA_CRTC_CURSOR_START);