SK_XM_READ_4
sc_if->sk_xmac_rev = XM_XMAC_REV(SK_XM_READ_4(sc_if, XM_DEVID));
ctx.mode = SK_XM_READ_4(sc_if, XM_MODE);
SK_XM_WRITE_4(sc, reg, (SK_XM_READ_4(sc, reg)) | (x))
SK_XM_WRITE_4(sc, reg, (SK_XM_READ_4(sc, reg)) & ~(x))