1// Copyright 2014, VIXL authors
2// All rights reserved.
3//
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5// modification, are permitted provided that the following conditions are met:
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15//
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25// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27#include "examples.h"
28
29#define __ masm->
30
31void GenerateCheckBounds(MacroAssembler* masm) {
32  // uint64_t check_bounds(uint64_t value, uint64_t low, uint64_t high)
33  // Argument locations:
34  //   value -> x0
35  //   low   -> x1
36  //   high  -> x2
37
38  // First we compare 'value' with the 'low' bound. If x1 <= x0 the N flag will
39  // be cleared. This configuration can be checked with the 'pl' condition.
40  __ Cmp(x0, x1);
41
42  // Now we will compare 'value' and 'high' (x0 and x2) but only if the 'pl'
43  // condition is verified. If the condition is not verified, we will clear
44  // all the flags except the carry one (C flag).
45  __ Ccmp(x0, x2, CFlag, pl);
46
47  // We set x0 to 1 only if the 'ls' condition is satisfied.
48  // 'ls' performs the following test: !(C==1 && Z==0). If the previous
49  // comparison has been skipped we have C==1 and Z==0, so the 'ls' test
50  // will fail and x0 will be set to 0.
51  // Otherwise if the previous comparison occurred, x0 will be set to 1
52  // only if x0 is less than or equal to x2.
53  __ Cset(x0, ls);
54
55  __ Ret();
56}
57
58
59#ifndef TEST_EXAMPLES
60#ifdef VIXL_INCLUDE_SIMULATOR_AARCH64
61void run_function(Simulator* simulator,
62                  Instruction* function,
63                  uint64_t value,
64                  uint64_t low,
65                  uint64_t high) {
66  simulator->WriteXRegister(0, value);
67  simulator->WriteXRegister(1, low);
68  simulator->WriteXRegister(2, high);
69
70  simulator->RunFrom(function);
71  printf("%" PRIu64 " %s between %" PRIu64 " and %" PRIu64 "\n",
72         value,
73         simulator->ReadXRegister(0) ? "is" : "is not",
74         low,
75         high);
76
77  simulator->ResetState();
78}
79
80int main(void) {
81  MacroAssembler masm;
82  Decoder decoder;
83  Simulator simulator(&decoder);
84
85  // Generate the code for the example function.
86  Label check_bounds;
87  masm.Bind(&check_bounds);
88  GenerateCheckBounds(&masm);
89  masm.FinalizeCode();
90
91  // Run the example function.
92  Instruction* function = masm.GetLabelAddress<Instruction*>(&check_bounds);
93  run_function(&simulator, function, 546, 50, 1000);
94  run_function(&simulator, function, 62, 100, 200);
95  run_function(&simulator, function, 200, 100, 200);
96
97  return 0;
98}
99#else
100// Without the simulator there is nothing to test.
101int main(void) { return 0; }
102#endif  // VIXL_INCLUDE_SIMULATOR_AARCH64
103#endif  // TEST_EXAMPLES
104