// Copyright 2014, VIXL authors
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of ARM Limited nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "examples.h"
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#define __ masm->
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void GenerateFactorialRec(MacroAssembler* masm) {
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// uint64_t factorial_rec(uint64_t n)
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// Argument location:
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// n -> x0
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Label entry, input_is_zero;
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__ Bind(&entry);
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// Check for the stopping condition: the input number is null.
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__ Cbz(x0, &input_is_zero);
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__ Mov(x1, x0);
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__ Sub(x0, x0, 1);
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__ Push(x1, lr);
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__ Bl(&entry); // Recursive call factorial_rec(n - 1).
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__ Pop(lr, x1);
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__ Mul(x0, x0, x1);
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__ Ret();
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__ Bind(&input_is_zero);
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__ Mov(x0, 1);
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__ Ret();
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}
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#ifndef TEST_EXAMPLES
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#ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
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int main(void) {
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MacroAssembler masm;
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Decoder decoder;
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Simulator simulator(&decoder);
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// Generate the code for the example function.
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Label factorial_rec;
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masm.Bind(&factorial_rec);
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GenerateFactorialRec(&masm);
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masm.FinalizeCode();
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// Run the example function.
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uint64_t input_val = 16;
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simulator.WriteXRegister(0, input_val);
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simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&factorial_rec));
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printf("factorial(%" PRIu64 ") = %" PRId64 "\n",
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input_val,
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simulator.ReadXRegister(0));
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return 0;
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}
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#else
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// Without the simulator there is nothing to test.
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int main(void) { return 0; }
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#endif // VIXL_INCLUDE_SIMULATOR_AARCH64
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#endif // TEST_EXAMPLES
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