1 // Copyright 2014, 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
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21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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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
GenerateCheckBounds(MacroAssembler * masm)32 void GenerateCheckBounds(MacroAssembler* masm) {
33 // uint64_t check_bounds(uint64_t value, uint64_t low, uint64_t high)
34 // Argument locations:
35 // value -> x0
36 // low -> x1
37 // high -> x2
38
39 // First we compare 'value' with the 'low' bound. If x1 <= x0 the N flag will
40 // be cleared. This configuration can be checked with the 'pl' condition.
41 __ Cmp(x0, x1);
42
43 // Now we will compare 'value' and 'high' (x0 and x2) but only if the 'pl'
44 // condition is verified. If the condition is not verified, we will clear
45 // all the flags except the carry one (C flag).
46 __ Ccmp(x0, x2, CFlag, pl);
47
48 // We set x0 to 1 only if the 'ls' condition is satisfied.
49 // 'ls' performs the following test: !(C==1 && Z==0). If the previous
50 // comparison has been skipped we have C==1 and Z==0, so the 'ls' test
51 // will fail and x0 will be set to 0.
52 // Otherwise if the previous comparison occurred, x0 will be set to 1
53 // only if x0 is less than or equal to x2.
54 __ Cset(x0, ls);
55
56 __ Ret();
57 }
58
59
60 #ifndef TEST_EXAMPLES
61 #ifdef USE_SIMULATOR
run_function(Simulator * simulator,Instruction * function,uint64_t value,uint64_t low,uint64_t high)62 void run_function(Simulator *simulator, Instruction * function,
63 uint64_t value, uint64_t low, uint64_t high) {
64 simulator->set_xreg(0, value);
65 simulator->set_xreg(1, low);
66 simulator->set_xreg(2, high);
67
68 simulator->RunFrom(function);
69 printf("%ld %s between %ld and %ld\n", value,
70 simulator->xreg(0) ? "is" : "is not",
71 low, high);
72
73 simulator->ResetState();
74 }
75
main(void)76 int main(void) {
77 // Create and initialize the assembler and the simulator.
78 byte assm_buf[BUF_SIZE];
79 MacroAssembler masm(assm_buf, BUF_SIZE);
80 Decoder decoder;
81 Simulator simulator(&decoder);
82
83 // Generate the code for the example function.
84 Label check_bounds;
85 masm.Bind(&check_bounds);
86 GenerateCheckBounds(&masm);
87 masm.FinalizeCode();
88
89 // Run the example function.
90 Instruction * function = masm.GetLabelAddress<Instruction*>(&check_bounds);
91 run_function(&simulator, function, 546, 50, 1000);
92 run_function(&simulator, function, 62, 100, 200);
93 run_function(&simulator, function, 200, 100, 200);
94
95 return 0;
96 }
97 #else
98 // Without the simulator there is nothing to test.
main(void)99 int main(void) { return 0; }
100 #endif // USE_SIMULATOR
101 #endif // TEST_EXAMPLES
102