[Qemu-devel] [PATCH v2 18/32] s390x/tcg: Implement VECTOR MERGE (HIGH|LOW)

[David Hildenbrand <david@redhat.com>]

We cannot use gvec expansion as source and destination elements are
have different element numbers. So we'll expand using a fancy loop.
Also, we have to take care of overlapping source and destination
registers, therefore use a safe evaluation irder depending on the
operation.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/insn-data.def      |  4 ++++
 target/s390x/translate_vx.inc.c | 42 +++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
index 3c0b14bafd..f7232f8615 100644
--- a/target/s390x/insn-data.def
+++ b/target/s390x/insn-data.def
@@ -1010,6 +1010,10 @@
     F(0xe762, VLVGP,   VRR_f, V,   r2, r3, 0, 0, vlvgp, 0, IF_VEC)
 /* VECTOR LOAD WITH LENGTH */
     F(0xe737, VLL,     VRS_b, V,   la2, r3_32u, 0, 0, vll, 0, IF_VEC)
+/* VECTOR MERGE HIGH */
+    F(0xe761, VMRH,    VRR_c, V,   0, 0, 0, 0, vmr, 0, IF_VEC)
+/* VECTOR MERGE LOW */
+    F(0xe760, VMRL,    VRR_c, V,   0, 0, 0, 0, vmr, 0, IF_VEC)
 
 #ifndef CONFIG_USER_ONLY
 /* COMPARE AND SWAP AND PURGE */
diff --git a/target/s390x/translate_vx.inc.c b/target/s390x/translate_vx.inc.c
index 0ce9de2332..35a63cd3db 100644
--- a/target/s390x/translate_vx.inc.c
+++ b/target/s390x/translate_vx.inc.c
@@ -526,3 +526,45 @@ static DisasJumpType op_vll(DisasContext *s, DisasOps *o)
     tcg_temp_free_ptr(a0);
     return DISAS_NEXT;
 }
+
+static DisasJumpType op_vmr(DisasContext *s, DisasOps *o)
+{
+    const uint8_t v1 = get_field(s->fields, v1);
+    const uint8_t v2 = get_field(s->fields, v2);
+    const uint8_t v3 = get_field(s->fields, v3);
+    const uint8_t es = get_field(s->fields, m4);
+    int dst_idx, src_idx;
+    TCGv_i64 tmp;
+
+    if (es > ES_64) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return DISAS_NORETURN;
+    }
+
+    tmp = tcg_temp_new_i64();
+    if (s->fields->op2 == 0x61) {
+        /* iterate backwards to avoid overwriting data we might need later */
+        for (dst_idx = NUM_VEC_ELEMENTS(es) - 1; dst_idx >= 0; dst_idx--) {
+            src_idx = dst_idx / 2;
+            if (dst_idx % 2 == 0) {
+                read_vec_element_i64(tmp, v2, src_idx, es);
+            } else {
+                read_vec_element_i64(tmp, v3, src_idx, es);
+            }
+            write_vec_element_i64(tmp, v1, dst_idx, es);
+        }
+    } else {
+        /* iterate forward to avoid overwriting data we might need later */
+        for (dst_idx = 0; dst_idx < NUM_VEC_ELEMENTS(es); dst_idx++) {
+            src_idx = (dst_idx + NUM_VEC_ELEMENTS(es)) / 2;
+            if (dst_idx % 2 == 0) {
+                read_vec_element_i64(tmp, v2, src_idx, es);
+            } else {
+                read_vec_element_i64(tmp, v3, src_idx, es);
+            }
+            write_vec_element_i64(tmp, v1, dst_idx, es);
+        }
+    }
+    tcg_temp_free_i64(tmp);
+    return DISAS_NEXT;
+}
-- 
2.17.2