VGA_GFX_COMPARE_MASK
vga_wgfx(cinfo->regbase, VGA_GFX_COMPARE_MASK, 0x0f);
vga_wgfx(regbase, VGA_GFX_COMPARE_MASK, 0x00);
vga_wgfx(regbase, VGA_GFX_COMPARE_MASK, 0x0F);
par->gdc[VGA_GFX_COMPARE_MASK] = 0x0F;
gdc[VGA_GFX_COMPARE_MASK] = 0x0F;