[Qemu-devel] [RFC 4/5] tcg-op: create new TCG qemu_ldlink and qemu_stcond instructions

[Alvise Rigo <a.rigo@virtualopensystems.com>]

Create a new pair of instructions that implement a LoadLink/StoreConditional
mechanism.

Suggested-by: Jani Kokkonen <jani.kokkonen@huawei.com>
Suggested-by: Claudio Fontana <claudio.fontana@huawei.com>
Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
---
 tcg/tcg-op.c  | 20 ++++++++++++++++++++
 tcg/tcg-op.h  |  3 +++
 tcg/tcg-opc.h |  4 ++++
 tcg/tcg.c     |  2 ++
 4 files changed, 29 insertions(+)

diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index 2b6be75..7c3e85b 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -1886,6 +1886,13 @@ static void gen_ldst_i32(TCGOpcode opc, TCGv_i32 val, TCGv addr,
 #endif
 }
 
+/* An output operand to return the StoreConditional result */
+static void gen_stcond_i32(TCGOpcode opc, TCGv_i32 is_dirty, TCGv_i32 val,
+                         TCGv addr, TCGMemOp memop, TCGArg idx)
+{
+    tcg_gen_op5ii_i32(opc, is_dirty, val, addr, memop, idx);
+}
+
 static void gen_ldst_i64(TCGOpcode opc, TCGv_i64 val, TCGv addr,
                          TCGMemOp memop, TCGArg idx)
 {
@@ -1913,12 +1920,25 @@ void tcg_gen_qemu_ld_i32(TCGv_i32 val, TCGv addr, TCGArg idx, TCGMemOp memop)
     gen_ldst_i32(INDEX_op_qemu_ld_i32, val, addr, memop, idx);
 }
 
+void tcg_gen_qemu_ldlink_i32(TCGv_i32 val, TCGv addr, TCGArg idx, TCGMemOp memop)
+{
+    memop = tcg_canonicalize_memop(memop, 0, 0);
+    gen_ldst_i32(INDEX_op_qemu_ldlink_i32, val, addr, memop, idx);
+}
+
 void tcg_gen_qemu_st_i32(TCGv_i32 val, TCGv addr, TCGArg idx, TCGMemOp memop)
 {
     memop = tcg_canonicalize_memop(memop, 0, 1);
     gen_ldst_i32(INDEX_op_qemu_st_i32, val, addr, memop, idx);
 }
 
+void tcg_gen_qemu_stcond_i32(TCGv_i32 is_dirty, TCGv_i32 val, TCGv addr,
+                           TCGArg idx, TCGMemOp memop)
+{
+    memop = tcg_canonicalize_memop(memop, 0, 1);
+    gen_stcond_i32(INDEX_op_qemu_stcond_i32, is_dirty, val, addr, memop, idx);
+}
+
 void tcg_gen_qemu_ld_i64(TCGv_i64 val, TCGv addr, TCGArg idx, TCGMemOp memop)
 {
     if (TCG_TARGET_REG_BITS == 32 && (memop & MO_SIZE) < MO_64) {
diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
index d1d763f..f183169 100644
--- a/tcg/tcg-op.h
+++ b/tcg/tcg-op.h
@@ -754,6 +754,9 @@ void tcg_gen_qemu_st_i32(TCGv_i32, TCGv, TCGArg, TCGMemOp);
 void tcg_gen_qemu_ld_i64(TCGv_i64, TCGv, TCGArg, TCGMemOp);
 void tcg_gen_qemu_st_i64(TCGv_i64, TCGv, TCGArg, TCGMemOp);
 
+void tcg_gen_qemu_ldlink_i32(TCGv_i32, TCGv, TCGArg, TCGMemOp);
+void tcg_gen_qemu_stcond_i32(TCGv_i32, TCGv_i32, TCGv, TCGArg, TCGMemOp);
+
 static inline void tcg_gen_qemu_ld8u(TCGv ret, TCGv addr, int mem_index)
 {
     tcg_gen_qemu_ld_tl(ret, addr, mem_index, MO_UB);
diff --git a/tcg/tcg-opc.h b/tcg/tcg-opc.h
index 42d0cfe..c88411c 100644
--- a/tcg/tcg-opc.h
+++ b/tcg/tcg-opc.h
@@ -183,6 +183,10 @@ DEF(qemu_ld_i32, 1, TLADDR_ARGS, 2,
     TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS)
 DEF(qemu_st_i32, 0, TLADDR_ARGS + 1, 2,
     TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS)
+DEF(qemu_ldlink_i32, 1, TLADDR_ARGS, 2,
+    TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS)
+DEF(qemu_stcond_i32, 1, TLADDR_ARGS + 1, 2,
+    TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS)
 DEF(qemu_ld_i64, DATA64_ARGS, TLADDR_ARGS, 2,
     TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS | TCG_OPF_64BIT)
 DEF(qemu_st_i64, 0, TLADDR_ARGS + DATA64_ARGS, 2,
diff --git a/tcg/tcg.c b/tcg/tcg.c
index f1558b7..368f6ae 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -1068,6 +1068,8 @@ void tcg_dump_ops(TCGContext *s)
                 i = 1;
                 break;
             case INDEX_op_qemu_ld_i32:
+            case INDEX_op_qemu_ldlink_i32:
+            case INDEX_op_qemu_stcond_i32:
             case INDEX_op_qemu_st_i32:
             case INDEX_op_qemu_ld_i64:
             case INDEX_op_qemu_st_i64:
-- 
2.4.0