1// Copyright 2013, 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 "examples.h" 28 29#define BUF_SIZE (4096) 30#define __ masm-> 31 32void GenerateFactorialRec(MacroAssembler* masm) { 33 // uint64_t factorial_rec(uint64_t n) 34 // Argument location: 35 // n -> x0 36 37 Label entry, input_is_zero; 38 39 __ Bind(&entry); 40 // Check for the stopping condition: the input number is null. 41 __ Cbz(x0, &input_is_zero); 42 43 __ Mov(x1, x0); 44 __ Sub(x0, x0, 1); 45 __ Push(x1, lr); 46 __ Bl(&entry); // Recursive call factorial_rec(n - 1). 47 __ Pop(lr, x1); 48 __ Mul(x0, x0, x1); 49 __ Ret(); 50 51 __ Bind(&input_is_zero); 52 __ Mov(x0, 1); 53 __ Ret(); 54} 55 56 57#ifndef TEST_EXAMPLES 58int main(void) { 59 // Create and initialize the assembler and the simulator. 60 byte assm_buf[BUF_SIZE]; 61 MacroAssembler masm(assm_buf, BUF_SIZE); 62 Decoder decoder; 63 Simulator simulator(&decoder); 64 65 // Generate the code for the example function. 66 Label factorial_rec; 67 masm.Bind(&factorial_rec); 68 GenerateFactorialRec(&masm); 69 masm.FinalizeCode(); 70 71 // Run the example function. 72 uint64_t input_val = 16; 73 simulator.set_xreg(0, input_val); 74 simulator.RunFrom(factorial_rec.target()); 75 printf("factorial(%ld) = %ld\n", input_val, simulator.xreg(0)); 76 77 return 0; 78} 79#endif 80