ppc: refactor atomic exchange

Change-Id: I01c4a68377a70cfed425b3cd1ed56b120c9b5056
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3174627Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/main@{#76992}

src/codegen/ppc/macro-assembler-ppc.h

@@ -395,6 +395,17 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
     sync();
   }
 
+  template <class _type>
+  void AtomicExchange(MemOperand dst, Register new_value, Register output) {
+    Label exchange;
+    lwsync();
+    bind(&exchange);
+    LoadReserve<_type>(output, dst);
+    StoreConditional<_type>(new_value, dst);
+    bne(&exchange, cr0);
+    sync();
+  }
+
   template <class _type, class bin_op>
   void AtomicOps(MemOperand dst, Register value, Register output,
                  Register scratch, bin_op op) {

src/compiler/backend/ppc/code-generator-ppc.cc

@@ -1981,24 +1981,34 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kAtomicLoadInt16:
       UNREACHABLE();
     case kAtomicExchangeInt8:
-      ASSEMBLE_ATOMIC_EXCHANGE_INTEGER(lbarx, stbcx);
-      __ extsb(i.OutputRegister(0), i.OutputRegister(0));
+      __ AtomicExchange<int8_t>(
+          MemOperand(i.InputRegister(0), i.InputRegister(1)),
+          i.InputRegister(2), i.OutputRegister());
       break;
     case kPPC_AtomicExchangeUint8:
-      ASSEMBLE_ATOMIC_EXCHANGE_INTEGER(lbarx, stbcx);
+      __ AtomicExchange<uint8_t>(
+          MemOperand(i.InputRegister(0), i.InputRegister(1)),
+          i.InputRegister(2), i.OutputRegister());
       break;
     case kAtomicExchangeInt16:
-      ASSEMBLE_ATOMIC_EXCHANGE_INTEGER(lharx, sthcx);
-      __ extsh(i.OutputRegister(0), i.OutputRegister(0));
+      __ AtomicExchange<int16_t>(
+          MemOperand(i.InputRegister(0), i.InputRegister(1)),
+          i.InputRegister(2), i.OutputRegister());
       break;
     case kPPC_AtomicExchangeUint16:
-      ASSEMBLE_ATOMIC_EXCHANGE_INTEGER(lharx, sthcx);
+      __ AtomicExchange<uint16_t>(
+          MemOperand(i.InputRegister(0), i.InputRegister(1)),
+          i.InputRegister(2), i.OutputRegister());
       break;
     case kPPC_AtomicExchangeWord32:
-      ASSEMBLE_ATOMIC_EXCHANGE_INTEGER(lwarx, stwcx);
+      __ AtomicExchange<uint32_t>(
+          MemOperand(i.InputRegister(0), i.InputRegister(1)),
+          i.InputRegister(2), i.OutputRegister());
       break;
     case kPPC_AtomicExchangeWord64:
-      ASSEMBLE_ATOMIC_EXCHANGE_INTEGER(ldarx, stdcx);
+      __ AtomicExchange<uint64_t>(
+          MemOperand(i.InputRegister(0), i.InputRegister(1)),
+          i.InputRegister(2), i.OutputRegister());
       break;
     case kAtomicCompareExchangeInt8:
       __ AtomicCompareExchange<int8_t>(