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