1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
// Copyright 2015, VIXL authors
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of ARM Limited nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "examples.h"
#define __ masm->
void GenerateCrc32(MacroAssembler* masm) {
// uint32_t crc32(const char *msg, size_t length)
// Argument location:
// msg (pointer) -> x0
// length (integer) -> x1
// This example computes CRC32CB on an input array of a given size
// and returns the resulting checksum in w0.
Label loop, end;
// Move input array to temp register so we can re-use w0 as return register.
__ Mov(x2, x0);
// Initial remainder for the checksum. If length=0, then this value will be
// returned.
__ Mov(w0, 0xffffffff);
// Loop for iterating through the array, starting at msg[0].
__ Bind(&loop);
// If no more elements to process, then exit function.
__ Cbz(x1, &end);
__ Sub(x1, x1, 1);
// Compute checksum for msg[i].
__ Ldrb(w3, MemOperand(x2, 1, PostIndex));
__ Crc32b(w0, w0, w3);
__ B(&loop);
__ Bind(&end);
__ Ret();
}
#ifndef TEST_EXAMPLES
void runExample(const char* msg) {
MacroAssembler masm;
// Generate the code for the example function.
Label func;
masm.Bind(&func);
GenerateCrc32(&masm);
masm.FinalizeCode();
#ifdef VIXL_INCLUDE_SIMULATOR
// Run example function in the simulator.
uintptr_t msg_addr = reinterpret_cast<uintptr_t>(msg);
size_t msg_size = strlen(msg);
Decoder decoder;
Simulator simulator(&decoder);
simulator.WriteXRegister(0, msg_addr);
simulator.WriteXRegister(1, msg_size);
simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&func));
printf("crc32(\"%s\")=0x%x\n", msg, simulator.ReadWRegister(0));
#else
// Run example function natively.
printf("Not yet implemented.\n");
USE(msg);
#endif // VIXL_INCLUDE_SIMULATOR
}
int main(void) {
runExample("Hello World!");
runExample("do");
runExample("1");
runExample("");
return 0;
}
#endif // TEST_EXAMPLES
|
