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
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25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27 #include "examples.h"
28
29 using namespace vixl;
30 using namespace vixl::aarch64;
31
32 #define __ masm->
33
GenerateAbs(MacroAssembler * masm)34 void GenerateAbs(MacroAssembler* masm) {
35 // int64_t abs(int64_t x)
36 // Argument location:
37 // x -> x0
38
39 // This example uses a conditional instruction (cneg) to compute the
40 // absolute value of an integer.
41 __ Cmp(x0, 0);
42 __ Cneg(x0, x0, mi);
43 __ Ret();
44 }
45
46
47 #ifndef TEST_EXAMPLES
48 #ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
main(void)49 int main(void) {
50 MacroAssembler masm;
51 Decoder decoder;
52 Simulator simulator(&decoder);
53
54 // Generate the code for the example function.
55 Label abs;
56 masm.Bind(&abs);
57 GenerateAbs(&masm);
58 masm.FinalizeCode();
59
60 // Run the example function.
61 int64_t input_value = -42;
62 simulator.WriteXRegister(0, input_value);
63 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&abs));
64 printf("abs(%" PRId64 ") = %" PRId64 "\n",
65 input_value,
66 simulator.ReadXRegister(0));
67
68 return 0;
69 }
70 #else
71 // Without the simulator there is nothing to test.
main(void)72 int main(void) { return 0; }
73 #endif // VIXL_INCLUDE_SIMULATOR_AARCH64
74 #endif // TEST_EXAMPLES
75