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26 
27 #include "examples.h"
28 
29 #define ARRAY_SIZE(Array) (sizeof(Array) / sizeof((Array)[0]))
30 #define BUF_SIZE (4096)
31 #define __ masm->
32 
GenerateSumArray(MacroAssembler * masm)33 void GenerateSumArray(MacroAssembler* masm) {
34   // uint32_t sum_array(uint8_t* array, uint32_t size)
35   //  Argument locations:
36   //    array (pointer) -> x0
37   //    size            -> x1
38 
39   Label loop, end;
40 
41   __ Mov(x2, x0);
42   __ Mov(w0, 0);
43 
44   // There's nothing to do if the array is empty.
45   __ Cbz(w1, &end);
46 
47   // Go through the array and sum the elements.
48   __ Bind(&loop);
49 
50   __ Ldrb(w3, MemOperand(x2, 1, PostIndex));  // w3 = *(x2++)
51   __ Add(w0, w0, w3);
52 
53   __ Sub(w1, w1, 1);
54   __ Cbnz(w1, &loop);
55 
56   __ Bind(&end);
57   __ Ret();
58 }
59 
60 
61 #ifndef TEST_EXAMPLES
62 #ifdef USE_SIMULATOR
main(void)63 int main(void) {
64   // Create and initialize the assembler and the simulator.
65   byte assm_buf[BUF_SIZE];
66   MacroAssembler masm(assm_buf, BUF_SIZE);
67   Decoder decoder;
68   Simulator simulator(&decoder);
69 
70   // Generate the code for the example function.
71   Label sum_array;
72   masm.Bind(&sum_array);
73   GenerateSumArray(&masm);
74   masm.FinalizeCode();
75 
76   // Run the example function.
77   uint8_t data[] = { 2, 45, 63, 7, 245, 38 };
78   uintptr_t data_addr = reinterpret_cast<uintptr_t>(data);
79   simulator.set_xreg(0, data_addr);
80   simulator.set_xreg(1, ARRAY_SIZE(data));
81   simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&sum_array));
82 
83   unsigned int i;
84   for (i = 0; i < ARRAY_SIZE(data) - 1; ++i) {
85     printf("%d + ", data[i]);
86   }
87   printf("%d = %d\n", data[i], simulator.wreg(0));
88 
89   return 0;
90 }
91 #else
92 // Without the simulator there is nothing to test.
main(void)93 int main(void) { return 0; }
94 #endif  // USE_SIMULATOR
95 #endif  // TEST_EXAMPLES
96