[Qemu-devel] [PATCH 2/7] target/s390x: add BAL and BALR instructions

[Pavel Zbitskiy]

These instructions are provided for compatibility purposes and are
used only by old software, in the new code BAS and BASR are preferred.
The difference between the old and new instruction exists only in the
24-bit mode.

In addition, fix BAS polluting high 32 bits of the first operand in
24- and 31-bit addressing modes.

Signed-off-by: Pavel Zbitskiy <pavel.zbits...@gmail.com>
---
 target/s390x/insn-data.def |  3 +++
 target/s390x/translate.c   | 55 +++++++++++++++++++++++++++++++++-----
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
index 5c6f33ed9c..9c7b434fca 100644
--- a/target/s390x/insn-data.def
+++ b/target/s390x/insn-data.def
@@ -102,6 +102,9 @@
     D(0x9400, NI,      SI,    Z,   la1, i2_8u, new, 0, ni, nz64, MO_UB)
     D(0xeb54, NIY,     SIY,   LD,  la1, i2_8u, new, 0, ni, nz64, MO_UB)
 
+/* BRANCH AND LINK */
+    C(0x0500, BALR,    RR_a,  Z,   0, r2_nz, r1, 0, bal, 0)
+    C(0x4500, BAL,     RX_a,  Z,   0, a2, r1, 0, bal, 0)
 /* BRANCH AND SAVE */
     C(0x0d00, BASR,    RR_a,  Z,   0, r2_nz, r1, 0, bas, 0)
     C(0x4d00, BAS,     RX_a,  Z,   0, a2, r1, 0, bas, 0)
diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 57c03cbf58..111d575c41 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -84,14 +84,22 @@ static uint64_t inline_branch_hit[CC_OP_MAX];
 static uint64_t inline_branch_miss[CC_OP_MAX];
 #endif
 
-static uint64_t pc_to_link_info(DisasContext *s, uint64_t pc)
+static void pc_to_link_info(TCGv_i64 out, DisasContext *s, uint64_t pc)
 {
-    if (!(s->base.tb->flags & FLAG_MASK_64)) {
-        if (s->base.tb->flags & FLAG_MASK_32) {
-            return pc | 0x80000000;
+    TCGv_i64 tmp;
+
+    if (s->base.tb->flags & FLAG_MASK_32) {
+        if (s->base.tb->flags & FLAG_MASK_64) {
+            tcg_gen_movi_i64(out, pc);
+            return;
         }
+        pc |= 0x80000000;
     }
-    return pc;
+    assert(!(s->base.tb->flags & FLAG_MASK_64));
+    tmp = tcg_temp_new_i64();
+    tcg_gen_movi_i64(tmp, pc);
+    tcg_gen_deposit_i64(out, out, tmp, 0, 32);
+    tcg_temp_free_i64(tmp);
 }
 
 static TCGv_i64 psw_addr;
@@ -1453,7 +1461,40 @@ static DisasJumpType op_ni(DisasContext *s, DisasOps *o)
 
 static DisasJumpType op_bas(DisasContext *s, DisasOps *o)
 {
-    tcg_gen_movi_i64(o->out, pc_to_link_info(s, s->pc_tmp));
+    pc_to_link_info(o->out, s, s->pc_tmp);
+    if (o->in2) {
+        tcg_gen_mov_i64(psw_addr, o->in2);
+        per_branch(s, false);
+        return DISAS_PC_UPDATED;
+    } else {
+        return DISAS_NEXT;
+    }
+}
+
+static void save_link_info(DisasContext *s, DisasOps *o)
+{
+    TCGv_i64 t;
+
+    if (s->base.tb->flags & (FLAG_MASK_32 | FLAG_MASK_64)) {
+        pc_to_link_info(o->out, s, s->pc_tmp);
+        return;
+    }
+    gen_op_calc_cc(s);
+    tcg_gen_andi_i64(o->out, o->out, 0xffffffff00000000ull);
+    tcg_gen_ori_i64(o->out, o->out, ((s->ilen / 2) << 30) | s->pc_tmp);
+    t = tcg_temp_new_i64();
+    tcg_gen_shri_i64(t, psw_mask, 16);
+    tcg_gen_andi_i64(t, t, 0x0f000000);
+    tcg_gen_or_i64(o->out, o->out, t);
+    tcg_gen_extu_i32_i64(t, cc_op);
+    tcg_gen_shli_i64(t, t, 28);
+    tcg_gen_or_i64(o->out, o->out, t);
+    tcg_temp_free_i64(t);
+}
+
+static DisasJumpType op_bal(DisasContext *s, DisasOps *o)
+{
+    save_link_info(s, o);
     if (o->in2) {
         tcg_gen_mov_i64(psw_addr, o->in2);
         per_branch(s, false);
@@ -1465,7 +1506,7 @@ static DisasJumpType op_bas(DisasContext *s, DisasOps *o)
 
 static DisasJumpType op_basi(DisasContext *s, DisasOps *o)
 {
-    tcg_gen_movi_i64(o->out, pc_to_link_info(s, s->pc_tmp));
+    pc_to_link_info(o->out, s, s->pc_tmp);
     return help_goto_direct(s, s->base.pc_next + 2 * get_field(s->fields, i2));
 }
 
-- 
2.18.0