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      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
     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 <sys/time.h>
     28 #include "globals-vixl.h"
     29 
     30 #include "aarch64/instructions-aarch64.h"
     31 #include "aarch64/macro-assembler-aarch64.h"
     32 
     33 using namespace vixl;
     34 using namespace vixl::aarch64;
     35 
     36 static const int kDefaultInstructionCount = 100000;
     37 
     38 // This program focuses on emitting branch instructions.
     39 //
     40 // This code will emit a given number of branch immediate to the next
     41 // instructions in a fixed size buffer, looping over the buffer if necessary.
     42 // This code therefore focuses on Emit and label binding/patching.
     43 int main(int argc, char* argv[]) {
     44   int instructions = 0;
     45 
     46   switch (argc) {
     47     case 1:
     48       instructions = kDefaultInstructionCount;
     49       break;
     50     case 2:
     51       instructions = atoi(argv[1]);
     52       break;
     53     default:
     54       printf("Usage: %s [#instructions]\n", argv[0]);
     55       exit(1);
     56   }
     57 
     58   const int buffer_size = 256 * KBytes;
     59   const int buffer_instruction_count = buffer_size / kInstructionSize;
     60   timeval start;
     61   gettimeofday(&start, NULL);
     62   MacroAssembler masm(buffer_size);
     63 
     64 #define __ masm.
     65   // We emit a branch to the next instruction.
     66 
     67   int rounds = instructions / buffer_instruction_count;
     68   for (int i = 0; i < rounds; ++i) {
     69     {
     70       ExactAssemblyScope scope(&masm, buffer_size);
     71       for (int j = 0; j < buffer_instruction_count; ++j) {
     72         Label target;
     73         __ b(&target);
     74         __ bind(&target);
     75       }
     76     }
     77     masm.Reset();
     78   }
     79 
     80   int remaining = instructions % buffer_instruction_count;
     81   {
     82     ExactAssemblyScope scope(&masm, remaining * kInstructionSize);
     83     for (int i = 0; i < remaining; ++i) {
     84       Label target;
     85       __ b(&target);
     86       __ bind(&target);
     87     }
     88   }
     89 
     90   masm.FinalizeCode();
     91   timeval end;
     92   gettimeofday(&end, NULL);
     93   double delta = (end.tv_sec - start.tv_sec) +
     94                  static_cast<double>(end.tv_usec - start.tv_usec) / 1000000;
     95   printf("A64: time for %d instructions: %gs\n", instructions, delta);
     96 
     97   return 0;
     98 }
     99