1 // Copyright 2015, 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 "vixl/a64/macro-assembler-a64.h"
28 #include "vixl/a64/instructions-a64.h"
29 #include "vixl/globals.h"
30
31 using namespace vixl;
32
33 static const int 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.
main(int argc,char * argv[])40 int main(int argc, char* argv[]) {
41 int 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 int buffer_size = 256 * KBytes;
52 const int buffer_instruction_count = buffer_size / kInstructionSize;
53 MacroAssembler masm(buffer_size);
54
55 #define __ masm.
56 // We emit a branch to the next instruction.
57
58 int rounds = instructions / buffer_instruction_count;
59 for (int i = 0; i < rounds; ++i) {
60 {
61 InstructionAccurateScope scope(&masm, buffer_instruction_count);
62 for (int j = 0; j < buffer_instruction_count; ++j) {
63 Label target;
64 __ b(&target);
65 __ bind(&target);
66 }
67 }
68 masm.Reset();
69 }
70
71 int remaining = instructions % buffer_instruction_count;
72 {
73 InstructionAccurateScope scope(&masm, remaining);
74 for (int i = 0; i < remaining; ++i) {
75 Label target;
76 __ b(&target);
77 __ bind(&target);
78 }
79 }
80
81 masm.FinalizeCode();
82
83 return 0;
84 }
85