diff --git a/format.c b/format.c
index 0b861b0..17f0443 100644
--- a/format.c
+++ b/format.c
@@ -54,7 +54,16 @@ static void mm_sprintf_lite(kstring_t *s, const char *fmt, ...)
 	s->s[s->l] = 0;
 }
 
-void mm_write_paf(kstring_t *s, const mm_idx_t *mi, bseq1_t *t, mm_reg1_t *r)
+static inline void write_tags(kstring_t *s, const mm_reg1_t *r)
+{
+	mm_sprintf_lite(s, "\tcm:i:%d", r->cnt);
+	if (r->p) mm_sprintf_lite(s, "\ts1:i:%d", r->score);
+	if (r->parent == r->id) mm_sprintf_lite(s, "\ts2:i:%d", r->subsc);
+	if (r->split) mm_sprintf_lite(s, "\tzd:i:%d", r->split);
+	if (r->p) mm_sprintf_lite(s, "\tNM:i:%d\tAS:i:%d\tnn:i:%d", r->p->n_diff, r->p->score, r->p->n_ambi);
+}
+
+void mm_write_paf(kstring_t *s, const mm_idx_t *mi, const bseq1_t *t, const mm_reg1_t *r)
 {
 	s->l = 0;
 	mm_sprintf_lite(s, "%s\t%d\t%d\t%d\t%c\t", t->name, t->l_seq, r->qs, r->qe, "+-"[r->rev]);
@@ -63,12 +72,11 @@ void mm_write_paf(kstring_t *s, const mm_idx_t *mi, bseq1_t *t, mm_reg1_t *r)
 	mm_sprintf_lite(s, "\t%d\t%d\t%d", mi->seq[r->rid].len, r->rs, r->re);
 	if (r->p) mm_sprintf_lite(s, "\t%d\t%d", r->p->blen - r->p->n_ambi - r->p->n_diff, r->p->blen);
 	else mm_sprintf_lite(s, "\t%d\t%d", r->score, r->re - r->rs > r->qe - r->qs? r->re - r->rs : r->qe - r->qs);
-	mm_sprintf_lite(s, "\t%d\tcm:i:%d", r->mapq, r->cnt);
-	if (r->p) mm_sprintf_lite(s, "\ts1:i:%d", r->score);
-	if (r->parent == r->id) mm_sprintf_lite(s, "\ts2:i:%d", r->subsc);
+	mm_sprintf_lite(s, "\t%d", r->mapq);
+	write_tags(s, r);
 	if (r->p) {
 		uint32_t k;
-		mm_sprintf_lite(s, "\tNM:i:%d\tAS:i:%d\tnn:i:%d\tcg:Z:", r->p->n_diff, r->p->score, r->p->n_ambi);
+		mm_sprintf_lite(s, "cg:Z:");
 		for (k = 0; k < r->p->n_cigar; ++k)
 			mm_sprintf_lite(s, "%d%c", r->p->cigar[k]>>4, "MID"[r->p->cigar[k]&0xf]);
 	}
@@ -98,7 +106,7 @@ static void sam_write_sq(kstring_t *s, char *seq, int l, int rev, int comp)
 	} else str_copy(s, seq, seq + l);
 }
 
-void mm_write_sam(kstring_t *s, const mm_idx_t *mi, bseq1_t *t, mm_reg1_t *r)
+void mm_write_sam(kstring_t *s, const mm_idx_t *mi, const bseq1_t *t, const mm_reg1_t *r)
 {
 	int flag = 0;
 	s->l = 0;
@@ -115,8 +123,6 @@ void mm_write_sam(kstring_t *s, const mm_idx_t *mi, bseq1_t *t, mm_reg1_t *r)
 	} else mm_sprintf_lite(s, "*");
 	mm_sprintf_lite(s, "\t*\t0\t0\t");
 	sam_write_sq(s, t->seq, t->l_seq, r->rev, r->rev);
-	mm_sprintf_lite(s, "\t*\tcm:i:%d", r->cnt);
-	if (r->p) mm_sprintf_lite(s, "\ts1:i:%d", r->score);
-	if (r->parent == r->id) mm_sprintf_lite(s, "\ts2:i:%d", r->subsc);
-	if (r->p) mm_sprintf_lite(s, "\tNM:i:%d\tAS:i:%d\tnn:i:%d", r->p->n_diff, r->p->score, r->p->n_ambi);
+	mm_sprintf_lite(s, "\t*");
+	write_tags(s, r);
 }
diff --git a/hit.c b/hit.c
index d3408b8..ff42d2c 100644
--- a/hit.c
+++ b/hit.c
@@ -36,7 +36,7 @@ void mm_split_reg(mm_reg1_t *r, mm_reg1_t *r2, int n, int qlen, mm128_t *a)
 	r->cnt -= r2->cnt;
 	r->score -= r2->score;
 	mm_reg_set_coor(r, qlen, a);
-	r->split = r2->split = 1;
+	r->split |= 1, r2->split |= 2;
 }
 
 void mm_set_parent(void *km, float mask_level, int n, mm_reg1_t *r) // and compute mm_reg1_t::subsc
diff --git a/main.c b/main.c
index e0d4bfe..34a09ff 100644
--- a/main.c
+++ b/main.c
@@ -10,7 +10,7 @@
 #include "minimap.h"
 #include "mmpriv.h"
 
-#define MM_VERSION "2.0-r111-pre"
+#define MM_VERSION "2.0-r112-pre"
 
 void liftrlimit()
 {
diff --git a/minimap.h b/minimap.h
index 13fc7d4..04c3391 100644
--- a/minimap.h
+++ b/minimap.h
@@ -54,13 +54,13 @@ typedef struct {
 
 typedef struct {
 	int32_t id;
-	uint32_t cnt:30, rev:1, split:1;
+	uint32_t cnt:31, rev:1;
 	uint32_t rid:31, rep:1;
 	int32_t score;
 	int32_t qs, qe, rs, re;
 	int32_t parent, subsc;
 	int32_t as;
-	uint32_t mapq:8, n_sub:24; // TODO: n_sub is not used for now
+	uint32_t mapq:8, split:2, n_sub:22; // TODO: n_sub is not used for now
 	mm_extra_t *p;
 } mm_reg1_t;
 
diff --git a/mmpriv.h b/mmpriv.h
index 40397be..ee19d0f 100644
--- a/mmpriv.h
+++ b/mmpriv.h
@@ -31,8 +31,8 @@ void radix_sort_128x(mm128_t *beg, mm128_t *end);
 void radix_sort_64(uint64_t *beg, uint64_t *end);
 uint32_t ks_ksmall_uint32_t(size_t n, uint32_t arr[], size_t kk);
 
-void mm_write_paf(kstring_t *s, const mm_idx_t *mi, bseq1_t *t, mm_reg1_t *r);
-void mm_write_sam(kstring_t *s, const mm_idx_t *mi, bseq1_t *t, mm_reg1_t *r);
+void mm_write_paf(kstring_t *s, const mm_idx_t *mi, const bseq1_t *t, const mm_reg1_t *r);
+void mm_write_sam(kstring_t *s, const mm_idx_t *mi, const bseq1_t *t, const mm_reg1_t *r);
 int mm_chain_dp(int max_dist, int bw, int max_skip, int min_cnt, int min_sc, int64_t n, mm128_t *a, uint64_t **_u, void *km);
 mm_reg1_t *mm_align_skeleton(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int qlen, const char *qstr, int *n_regs_, mm_reg1_t *regs, mm128_t *a);