1// Copyright 2014, 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 "examples.h" 28 29#define __ masm-> 30 31void GenerateFactorialRec(MacroAssembler* masm) { 32 // uint64_t factorial_rec(uint64_t n) 33 // Argument location: 34 // n -> x0 35 36 Label entry, input_is_zero; 37 38 __ Bind(&entry); 39 // Check for the stopping condition: the input number is null. 40 __ Cbz(x0, &input_is_zero); 41 42 __ Mov(x1, x0); 43 __ Sub(x0, x0, 1); 44 __ Push(x1, lr); 45 __ Bl(&entry); // Recursive call factorial_rec(n - 1). 46 __ Pop(lr, x1); 47 __ Mul(x0, x0, x1); 48 __ Ret(); 49 50 __ Bind(&input_is_zero); 51 __ Mov(x0, 1); 52 __ Ret(); 53} 54 55 56#ifndef TEST_EXAMPLES 57#ifdef VIXL_INCLUDE_SIMULATOR_AARCH64 58int main(void) { 59 MacroAssembler masm; 60 Decoder decoder; 61 Simulator simulator(&decoder); 62 63 // Generate the code for the example function. 64 Label factorial_rec; 65 masm.Bind(&factorial_rec); 66 GenerateFactorialRec(&masm); 67 masm.FinalizeCode(); 68 69 // Run the example function. 70 uint64_t input_val = 16; 71 simulator.WriteXRegister(0, input_val); 72 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&factorial_rec)); 73 printf("factorial(%" PRIu64 ") = %" PRId64 "\n", 74 input_val, 75 simulator.ReadXRegister(0)); 76 77 return 0; 78} 79#else 80// Without the simulator there is nothing to test. 81int main(void) { return 0; } 82#endif // VIXL_INCLUDE_SIMULATOR_AARCH64 83#endif // TEST_EXAMPLES 84