MT_SKEY_1
#define MT_SKEY(_bss, _idx) (((_bss) & 8) ? MT_SKEY_1(_bss, _idx) : MT_SKEY_0(_bss, _idx))
((_bss & 8) ? MT_SKEY_1(_bss, _idx) : MT_SKEY_0(_bss, _idx))