diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
index 43ab1963c8..166ee7c80b 100644
--- a/target/s390x/insn-data.def
+++ b/target/s390x/insn-data.def
@@ -39,10 +39,10 @@
     C(0xb9d8, AHHLR,   RRF_a, HW,  r2_sr32, r3, new, r1_32h, add, adds32)
 /* ADD IMMEDIATE */
     C(0xc209, AFI,     RIL_a, EI,  r1, i2, new, r1_32, add, adds32)
-    C(0xeb6a, ASI,     SIY,   GIE, m1_32s, i2, new, m1_32, add, adds32)
+    D(0xeb6a, ASI,     SIY,   GIE, la1, i2, new, 0, asi, adds32, MO_TESL)
     C(0xecd8, AHIK,    RIE_d, DO,  r3, i2, new, r1_32, add, adds32)
     C(0xc208, AGFI,    RIL_a, EI,  r1, i2, r1, 0, add, adds64)
-    C(0xeb7a, AGSI,    SIY,   GIE, m1_64, i2, new, m1_64, add, adds64)
+    D(0xeb7a, AGSI,    SIY,   GIE, la1, i2, new, 0, asi, adds64, MO_TEQ)
     C(0xecd9, AGHIK,   RIE_d, DO,  r3, i2, r1, 0, add, adds64)
 /* ADD IMMEDIATE HIGH */
     C(0xcc08, AIH,     RIL_a, HW,  r1_sr32, i2, new, r1_32h, add, adds32)
@@ -70,9 +70,9 @@
     C(0xc20b, ALFI,    RIL_a, EI,  r1, i2_32u, new, r1_32, add, addu32)
     C(0xc20a, ALGFI,   RIL_a, EI,  r1, i2_32u, r1, 0, add, addu64)
 /* ADD LOGICAL WITH SIGNED IMMEDIATE */
-    C(0xeb6e, ALSI,    SIY,   GIE, m1_32u, i2, new, m1_32, add, addu32)
+    D(0xeb6e, ALSI,    SIY,   GIE, la1, i2, new, 0, asi, addu32, MO_TEUL)
     C(0xecda, ALHSIK,  RIE_d, DO,  r3, i2, new, r1_32, add, addu32)
-    C(0xeb7e, ALGSI,   SIY,   GIE, m1_64, i2, new, m1_64, add, addu64)
+    D(0xeb7e, ALGSI,   SIY,   GIE, la1, i2, new, 0, asi, addu64, MO_TEQ)
     C(0xecdb, ALGHSIK, RIE_d, DO,  r3, i2, r1, 0, add, addu64)
 /* ADD LOGICAL WITH SIGNED IMMEDIATE HIGH */
     C(0xcc0a, ALSIH,   RIL_a, HW,  r1_sr32, i2, new, r1_32h, add, addu32)
diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 08c1ace0d8..7ab8e853ab 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -1364,6 +1364,27 @@ static ExitStatus op_addc(DisasContext *s, DisasOps *o)
     return NO_EXIT;
 }
 
+static ExitStatus op_asi(DisasContext *s, DisasOps *o)
+{
+    o->in1 = tcg_temp_new_i64();
+
+    if (!s390_has_feat(S390_FEAT_STFLE_45)) {
+        tcg_gen_qemu_ld_tl(o->in1, o->addr1, get_mem_index(s), s->insn->data);
+    } else {
+        /* Perform the atomic addition in memory. */
+        tcg_gen_atomic_fetch_add_i64(o->in1, o->addr1, o->in2, get_mem_index(s),
+                                     s->insn->data);
+    }
+
+    /* Recompute also for atomic case: needed for setting CC. */
+    tcg_gen_add_i64(o->out, o->in1, o->in2);
+
+    if (!s390_has_feat(S390_FEAT_STFLE_45)) {
+        tcg_gen_qemu_st_tl(o->out, o->addr1, get_mem_index(s), s->insn->data);
+    }
+    return NO_EXIT;
+}
+
 static ExitStatus op_aeb(DisasContext *s, DisasOps *o)
 {
     gen_helper_aeb(o->out, cpu_env, o->in1, o->in2);