1// Copyright 2013, ARM Limited
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
17// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
20// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27#include "a64/macro-assembler-a64.h"
28#include "a64/instructions-a64.h"
29#include "globals-vixl.h"
30
31using namespace vixl;
32
33static const unsigned kDefaultInstructionCount = 100000;
34
35// This program focuses on emitting branch instructions.
36//
37// This code will emit a given number of branch immediate to the next
38// instructions in a fixed size buffer, looping over the buffer if necessary.
39// This code therefore focuses on Emit and label binding/patching.
40int main(int argc, char* argv[]) {
41  unsigned instructions = 0;
42
43  switch (argc) {
44    case 1: instructions = kDefaultInstructionCount; break;
45    case 2: instructions = atoi(argv[1]); break;
46    default:
47      printf("Usage: %s [#instructions]\n", argv[0]);
48      exit(1);
49  }
50
51  const unsigned buffer_size = 256 * KBytes;
52  // Emitting on the last word of the buffer will trigger an assert.
53  const unsigned buffer_instruction_count = buffer_size / kInstructionSize - 1;
54
55  byte* assm_buffer = new byte[buffer_size];
56  MacroAssembler* masm = new MacroAssembler(assm_buffer, buffer_size);
57
58  #define __ masm->
59  // We emit a branch to the next instruction.
60
61  unsigned rounds = instructions / buffer_instruction_count;
62  for (unsigned i = 0; i < rounds; ++i) {
63    for (unsigned j = 0; j < buffer_instruction_count; ++j) {
64      Label target;
65      __ b(&target);
66      __ bind(&target);
67    }
68    masm->Reset();
69  }
70
71  unsigned remaining = instructions % buffer_instruction_count;
72  for (unsigned i = 0; i < remaining; ++i) {
73    Label target;
74    __ b(&target);
75    __ bind(&target);
76  }
77
78  delete masm;
79  delete assm_buffer;
80
81  return 0;
82}
83