1 files changed, 101 insertions, 0 deletions
diff --git a/examples/aarch64/swap-int32.cc b/examples/aarch64/swap-int32.cc
new file mode 100644
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+++ b/examples/aarch64/swap-int32.cc
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+// Copyright 2014, VIXL authors
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+//   * Redistributions of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//   * Redistributions in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//   * Neither the name of ARM Limited nor the names of its contributors may be
+//     used to endorse or promote products derived from this software without
+//     specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "examples.h"
+
+#define __ masm->
+
+void GenerateSwapInt32(MacroAssembler* masm) {
+  {
+    // In this scope the register x2 will be used by the macro-assembler
+    // as the stack pointer (via peek, poke, push, etc).
+    const Register old_stack_pointer = __ StackPointer();
+    __ Mov(x2, __ StackPointer());
+    __ SetStackPointer(x2);
+
+    // This call to Claim is not 16-byte aligned and would have failed
+    // if the current stack pointer was sp.
+    __ Claim(8);
+
+    __ Poke(w0, 0);
+    __ Poke(w1, 4);
+    __ Peek(w1, 0);
+    __ Peek(w0, 4);
+
+    __ Drop(8);
+
+    // Even if we didn't use the system stack pointer, sp might have been
+    // modified because the ABI forbids access to memory below the stack
+    // pointer.
+    __ Mov(old_stack_pointer, __ StackPointer());
+    __ SetStackPointer(old_stack_pointer);
+  }
+
+  // The stack pointer has now been switched back to sp.
+  __ Ret();
+}
+
+
+#ifndef TEST_EXAMPLES
+#ifdef VIXL_INCLUDE_SIMULATOR
+int main(void) {
+  MacroAssembler masm;
+  Decoder decoder;
+  Simulator simulator(&decoder);
+
+  // Generate the code for the example function.
+  Label swap_int32;
+  masm.Bind(&swap_int32);
+  GenerateSwapInt32(&masm);
+  masm.FinalizeCode();
+
+  // Run the example function.
+  simulator.WriteWRegister(0, 0x11111111);
+  simulator.WriteWRegister(1, 0x22222222);
+
+  // clang-format off
+  printf("Before swap_int32:\n"
+         "x0 = 0x%" PRIx32 "\n"
+         "x1 = 0x%" PRIx32 "\n",
+         simulator.ReadWRegister(0), simulator.ReadWRegister(1));
+  // clang-format on
+
+  simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&swap_int32));
+
+  // clang-format off
+  printf("After swap_int32:\n"
+         "x0 = 0x%" PRIx32 "\n"
+         "x1 = 0x%" PRIx32 "\n",
+         simulator.ReadWRegister(0), simulator.ReadWRegister(1));
+  // clang-format on
+
+  return 0;
+}
+#else
+// Without the simulator there is nothing to test.
+int main(void) { return 0; }
+#endif  // VIXL_INCLUDE_SIMULATOR
+#endif  // TEST_EXAMPLES