s390x/tcg: Implement VECTOR LOAD MULTIPLE

Try to load the last element first. Access to the first element will
be checked afterwards. This way, we can guarantee that the vector is
not modified before we checked for all possible exceptions. (16 vectors
cannot cross more than two pages)
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20190307121539.12842-14-david@redhat.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

target/s390x/insn-data.def

@@ -1000,6 +1000,8 @@
     F(0xe721, VLGV,    VRS_c, V,   la2, 0, r1, 0, vlgv, 0, IF_VEC)
 /* VECTOR LOAD LOGICAL ELEMENT AND ZERO */
     F(0xe704, VLLEZ,   VRX,   V,   la2, 0, 0, 0, vllez, 0, IF_VEC)
+/* VECTOR LOAD MULTIPLE */
+    F(0xe736, VLM,     VRS_a, V,   la2, 0, 0, 0, vlm, 0, IF_VEC)
 
 #ifndef CONFIG_USER_ONLY
 /* COMPARE AND SWAP AND PURGE */

target/s390x/translate_vx.inc.c

@@ -406,3 +406,43 @@ static DisasJumpType op_vllez(DisasContext *s, DisasOps *o)
     tcg_temp_free_i64(t);
     return DISAS_NEXT;
 }
+
+static DisasJumpType op_vlm(DisasContext *s, DisasOps *o)
+{
+    const uint8_t v3 = get_field(s->fields, v3);
+    uint8_t v1 = get_field(s->fields, v1);
+    TCGv_i64 t0, t1;
+
+    if (v3 < v1 || (v3 - v1 + 1) > 16) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return DISAS_NORETURN;
+    }
+
+    /*
+     * Check for possible access exceptions by trying to load the last
+     * element. The first element will be checked first next.
+     */
+    t0 = tcg_temp_new_i64();
+    t1 = tcg_temp_new_i64();
+    gen_addi_and_wrap_i64(s, t0, o->addr1, (v3 - v1) * 16 + 8);
+    tcg_gen_qemu_ld_i64(t0, t0, get_mem_index(s), MO_TEQ);
+
+    for (;; v1++) {
+        tcg_gen_qemu_ld_i64(t1, o->addr1, get_mem_index(s), MO_TEQ);
+        write_vec_element_i64(t1, v1, 0, ES_64);
+        if (v1 == v3) {
+            break;
+        }
+        gen_addi_and_wrap_i64(s, o->addr1, o->addr1, 8);
+        tcg_gen_qemu_ld_i64(t1, o->addr1, get_mem_index(s), MO_TEQ);
+        write_vec_element_i64(t1, v1, 1, ES_64);
+        gen_addi_and_wrap_i64(s, o->addr1, o->addr1, 8);
+    }
+
+    /* Store the last element, loaded first */
+    write_vec_element_i64(t0, v1, 1, ES_64);
+
+    tcg_temp_free_i64(t0);
+    tcg_temp_free_i64(t1);
+    return DISAS_NEXT;
+}