// Copyright 2015, ARM Limited // 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 "vixl/a64/macro-assembler-a64.h" #include "vixl/a64/instructions-a64.h" #include "vixl/globals.h" using namespace vixl; static const int kDefaultInstructionCount = 100000; // This program focuses on emitting branch instructions. // // This code will emit a given number of branch immediate to the next // instructions in a fixed size buffer, looping over the buffer if necessary. // This code therefore focuses on Emit and label binding/patching. int main(int argc, char* argv[]) { int instructions = 0; switch (argc) { case 1: instructions = kDefaultInstructionCount; break; case 2: instructions = atoi(argv[1]); break; default: printf("Usage: %s [#instructions]\n", argv[0]); exit(1); } const int buffer_size = 256 * KBytes; const int buffer_instruction_count = buffer_size / kInstructionSize; MacroAssembler masm(buffer_size); #define __ masm. // We emit a branch to the next instruction. int rounds = instructions / buffer_instruction_count; for (int i = 0; i < rounds; ++i) { { InstructionAccurateScope scope(&masm, buffer_instruction_count); for (int j = 0; j < buffer_instruction_count; ++j) { Label target; __ b(&target); __ bind(&target); } } masm.Reset(); } int remaining = instructions % buffer_instruction_count; { InstructionAccurateScope scope(&masm, remaining); for (int i = 0; i < remaining; ++i) { Label target; __ b(&target); __ bind(&target); } } masm.FinalizeCode(); return 0; }