1 // Copyright 2014, ARM Limited
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26
27 #include "examples.h"
28
29 #define BUF_SIZE (4096)
30 #define __ masm->
31
GenerateFactorial(MacroAssembler * masm)32 void GenerateFactorial(MacroAssembler* masm) {
33 // uint64_t factorial(uint64_t n)
34 // Argument location:
35 // n -> x0
36
37 Label loop, end;
38
39 __ Mov(x1, x0);
40 __ Mov(x0, 1); // Use x0 as the accumulator.
41
42 __ Cbz(x1, &end); // Nothing to do if the input is null.
43
44 __ Bind(&loop);
45 __ Mul(x0, x0, x1);
46 __ Sub(x1, x1, 1);
47 __ Cbnz(x1, &loop);
48
49 __ Bind(&end);
50 // The return value is in x0.
51 __ Ret();
52 }
53
54
55 #ifndef TEST_EXAMPLES
56 #ifdef USE_SIMULATOR
main(void)57 int main(void) {
58 // Create and initialize the assembler and the simulator.
59 byte assm_buf[BUF_SIZE];
60 MacroAssembler masm(assm_buf, BUF_SIZE);
61 Decoder decoder;
62 Simulator simulator(&decoder);
63
64 // Generate the code for the example function.
65 Label factorial;
66 masm.Bind(&factorial);
67 GenerateFactorial(&masm);
68 masm.FinalizeCode();
69
70 // Run the example function.
71 uint64_t input_val = 16;
72 simulator.set_xreg(0, input_val);
73 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&factorial));
74 printf("factorial(%ld) = %ld\n", input_val, simulator.xreg(0));
75
76 return 0;
77 }
78 #else
79 // Without the simulator there is nothing to test.
main(void)80 int main(void) { return 0; }
81 #endif // USE_SIMULATOR
82 #endif // TEST_EXAMPLES
83