1 // Copyright 2013, 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
main(void)56 int main(void) {
57 // Create and initialize the assembler and the simulator.
58 byte assm_buf[BUF_SIZE];
59 MacroAssembler masm(assm_buf, BUF_SIZE);
60 Decoder decoder;
61 Simulator simulator(&decoder);
62
63 // Generate the code for the example function.
64 Label factorial;
65 masm.Bind(&factorial);
66 GenerateFactorial(&masm);
67 masm.FinalizeCode();
68
69 // Run the example function.
70 uint64_t input_val = 16;
71 simulator.set_xreg(0, input_val);
72 simulator.RunFrom(factorial.target());
73 printf("factorial(%ld) = %ld\n", input_val, simulator.xreg(0));
74
75 return 0;
76 }
77 #endif
78