1 // Copyright 2015, ARM Limited
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3 //
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5 // modification, are permitted provided that the following conditions are met:
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8 // this list of conditions and the following disclaimer.
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10 // this list of conditions and the following disclaimer in the documentation
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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 // Macro to compute the number of elements in a vector.
30 #define ARRAY_SIZE(Array) (sizeof(Array) / sizeof((Array)[0]))
31 #define BUF_SIZE (4096)
32 #define __ masm->
33
34 /*
35 * This example adds two vectors with 1-byte elements using NEON instructions,
36 * and returns the results in the first vector.
37 */
GenerateAdd2Vectors(MacroAssembler * masm)38 void GenerateAdd2Vectors(MacroAssembler* masm) {
39 // void add2_vectors(uint8_t *vec*, const uint8_t *vecB, unsigned size)
40 // Argument locations:
41 // vecA (pointer) -> x0
42 // vecB (pointer) -> x1
43 // size (integer) -> w2
44 // Result returned in vecA.
45
46 Label loop16, loopr, end;
47
48 // Loop to add vector elements in 16-byte chunks.
49 __ Bind(&loop16);
50
51 // Handle vectors smaller than 16-bytes in the remainder loop.
52 __ Cmp(w2, 16);
53 __ B(lo, &loopr);
54 __ Sub(w2, w2, 16);
55
56 // Add vectors in 16-byte chunks.
57 __ Ld1(v0.V16B(), MemOperand(x0));
58 __ Ld1(v1.V16B(), MemOperand(x1, 16, PostIndex));
59 __ Add(v0.V16B(), v0.V16B(), v1.V16B());
60 __ St1(v0.V16B(), MemOperand(x0, 16, PostIndex));
61
62 __ B(&loop16);
63
64 // Loop to add the remaining vector elements.
65 __ Bind(&loopr);
66
67 // If there are no more vector elements to process, then exit.
68 __ Cbz(w2, &end);
69 __ Sub(w2, w2, 1);
70
71 // Add remaining vector elements in 1-byte chunks.
72 __ Ldrb(w5, MemOperand(x0));
73 __ Ldrb(w6, MemOperand(x1, 1, PostIndex));
74 __ Add(w5, w5, w6);
75 __ Strb(w5, MemOperand(x0, 1, PostIndex));
76
77 __ B(&loopr);
78
79 __ Bind(&end);
80
81 __ Ret();
82 }
83
84
PrintVector(const uint8_t * vec,unsigned num)85 void PrintVector(const uint8_t *vec, unsigned num) {
86 unsigned i;
87 printf("( ");
88 if (num > 0) {
89 for (i = 0; i < num - 1; ++i) {
90 printf("%d, ", vec[i]);
91 }
92 printf("%d", vec[i]);
93 }
94 printf(" )\n");
95 }
96
97
98 #ifndef TEST_EXAMPLES
main(void)99 int main(void) {
100 // Create and initialize the assembler.
101 byte assm_buf[BUF_SIZE];
102 MacroAssembler masm(assm_buf, BUF_SIZE);
103
104 // Generate native code for the example function.
105 Label add2_vectors;
106 masm.Bind(&add2_vectors);
107 GenerateAdd2Vectors(&masm);
108 masm.FinalizeCode();
109
110 // Initialize input data for the example function.
111 uint8_t vecA[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
112 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
113 16, 17, 18, 19, 20};
114 uint8_t vecB[] = {16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
115 30, 31,
116 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
117 30, 31,
118 32, 33, 34, 35, 36};
119 uint8_t vecC[ARRAY_SIZE(vecA)];
120
121 // Check whether the number of elements in both vectors match.
122 assert(ARRAY_SIZE(vecA) == ARRAY_SIZE(vecB));
123
124 // Compute the result in C.
125 for (unsigned i = 0; i < ARRAY_SIZE(vecA); i++) {
126 vecC[i] = vecA[i] + vecB[i];
127 }
128
129 #ifdef USE_SIMULATOR
130 uintptr_t vecA_addr = reinterpret_cast<uintptr_t>(vecA);
131 uintptr_t vecB_addr = reinterpret_cast<uintptr_t>(vecB);
132
133 // Configure register environment in the simulator.
134 Decoder decoder;
135 Simulator simulator(&decoder);
136 simulator.set_xreg(0, vecA_addr);
137 simulator.set_xreg(1, vecB_addr);
138 simulator.set_xreg(2, ARRAY_SIZE(vecA));
139 PrintVector(vecA, ARRAY_SIZE(vecA));
140 printf(" +\n");
141 PrintVector(vecB, ARRAY_SIZE(vecB));
142
143 // Run the example function in the simulator.
144 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&add2_vectors));
145 printf(" =\n");
146 PrintVector(vecA, ARRAY_SIZE(vecA));
147 #else
148 // Placeholder to run test natively.
149 printf("Running tests natively is not supported yet.\n");
150 return 0;
151 #endif // USE_SIMULATOR
152 // Check that the computed value in NEON matches the C version.
153 for (unsigned i = 0; i < ARRAY_SIZE(vecA); i++) {
154 assert(vecC[i] == vecA[i]);
155 }
156
157 return 0;
158 }
159 #endif // TEST_EXAMPLES
160