CALLOUT_TYPE_BITS
#define TABLE_TO_SEQID(x) ((x) >> CALLOUT_TYPE_BITS)
callout_table_bits = CALLOUT_TYPE_BITS + bits;
#define CALLOUT_NTYPES (1 << CALLOUT_TYPE_BITS)
#define CALLOUT_TABLE(t, f) (((f) << CALLOUT_TYPE_BITS) | (t))
#define CALLOUT_TABLE_SEQID(ct) (CALLOUT_TABLE_NUM(ct) >> CALLOUT_TYPE_BITS)