1// Copyright 2015, VIXL authors
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are met:
6//
7//   * Redistributions of source code must retain the above copyright notice,
8//     this list of conditions and the following disclaimer.
9//   * Redistributions in binary form must reproduce the above copyright notice,
10//     this list of conditions and the following disclaimer in the documentation
11//     and/or other materials provided with the distribution.
12//   * Neither the name of ARM Limited nor the names of its contributors may be
13//     used to endorse or promote products derived from this software without
14//     specific prior written permission.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
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25// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27#include "examples.h"
28
29#define __ masm.
30
31#ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
32int64_t LiteralExample(int64_t a, int64_t b) {
33  // Create and initialize the macro-assembler and the simulator.
34  MacroAssembler masm;
35  Decoder decoder;
36  Simulator simulator(&decoder);
37
38  Literal<int64_t> automatically_placed_literal(111, masm.GetLiteralPool());
39  Literal<int64_t> manually_placed_literal(222);
40
41  // Generate some code.
42  Label start;
43  masm.Bind(&start);
44  {
45    ExactAssemblyScope scope(&masm,
46                             kInstructionSize + sizeof(int64_t),
47                             ExactAssemblyScope::kExactSize);
48    Label over_literal;
49    __ b(&over_literal);
50    __ place(&manually_placed_literal);
51    __ bind(&over_literal);
52  }
53  __ Ldr(x1, &manually_placed_literal);
54  __ Ldr(x2, &automatically_placed_literal);
55  __ Add(x0, x1, x2);
56  __ Ret();
57
58  masm.FinalizeCode();
59
60  // Usually, compilers will move the code to another place in memory before
61  // executing it. Emulate that.
62  size_t code_size = masm.GetSizeOfCodeGenerated();
63  uint8_t* code = reinterpret_cast<uint8_t*>(malloc(code_size));
64  if (code == NULL) {
65    return 1;
66  }
67  memcpy(code, masm.GetBuffer()->GetStartAddress<void*>(), code_size);
68
69  // Run the code.
70  simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&start));
71  printf("111 + 222 = %" PRId64 "\n", simulator.ReadXRegister(0));
72
73  // Now let's modify the values of the literals.
74  automatically_placed_literal.UpdateValue(a, code);
75  manually_placed_literal.UpdateValue(b, code);
76
77  // Run the code again.
78  simulator.RunFrom(reinterpret_cast<Instruction*>(code));
79  printf("%" PRId64 " + %" PRId64 " = %" PRId64 "\n",
80         a,
81         b,
82         simulator.ReadXRegister(0));
83
84  return simulator.ReadXRegister(0);
85}
86#endif
87
88#ifndef TEST_EXAMPLES
89#ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
90int main(void) {
91  VIXL_CHECK(LiteralExample(1, 2) == 3);
92  return 0;
93}
94#else
95// Without the simulator there is nothing to test.
96int main(void) { return 0; }
97#endif  // VIXL_INCLUDE_SIMULATOR_AARCH64
98#endif  // TEST_EXAMPLES
99