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/globals.h" 28 29#include "vixl/a64/macro-assembler-a64.h" 30#include "vixl/a64/instructions-a64.h" 31 32using namespace vixl; 33 34static const int kDefaultIterationCount = 100000; 35 36// This program focuses on emitting branch instructions targeting a label bound 37// very closely. Here the MacroAssembler is used. This exercises label binding 38// and patching mechanisms, as well as the veneer resolving mechanisms for 39// branches not requiring veneers. 40int main(int argc, char* argv[]) { 41 int iterations = 0; 42 43 switch (argc) { 44 case 1: iterations = kDefaultIterationCount; break; 45 case 2: iterations = atoi(argv[1]); break; 46 default: 47 printf("Usage: %s [#iterations]\n", argv[0]); 48 exit(1); 49 } 50 51 const int buffer_size = 256 * KBytes; 52 const int instructions_per_iteration = 4; 53 const int max_buffer_iterations = 54 buffer_size / (instructions_per_iteration * kInstructionSize); 55 56 MacroAssembler masm(buffer_size); 57 58#define __ masm. 59 60 for (int i = 0; i < iterations;) { 61 masm.Reset(); 62 for (int j = 0; (j < max_buffer_iterations) && (i < iterations); ++j, ++i) { 63 Label target; 64 __ B(&target); 65 __ B(eq, &target); 66 __ Cbz(x2, &target); 67 __ Tbz(x3, 2, &target); 68 __ Bind(&target); 69 } 70 } 71 72 masm.FinalizeCode(); 73 74 return 0; 75} 76