CR41
i810_writeb(CR_INDEX_CGA, mmio, CR41);
i810_writeb(CR_INDEX_CGA, mmio, CR41);
i810_writeb(CR_INDEX_CGA, mmio, CR41);
i810_writeb(CR_INDEX_CGA, mmio, CR41);
unsigned char CR40, CR41, CR42, CR43, CR45;
{VIACR, CR41, 0xFF, 0x80},