1 // Copyright 2014, ARM Limited
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26
27 #include "examples.h"
28
29 #define BUF_SIZE (4096)
30 #define __ masm->
31
GenerateFactorialRec(MacroAssembler * masm)32 void GenerateFactorialRec(MacroAssembler* masm) {
33 // uint64_t factorial_rec(uint64_t n)
34 // Argument location:
35 // n -> x0
36
37 Label entry, input_is_zero;
38
39 __ Bind(&entry);
40 // Check for the stopping condition: the input number is null.
41 __ Cbz(x0, &input_is_zero);
42
43 __ Mov(x1, x0);
44 __ Sub(x0, x0, 1);
45 __ Push(x1, lr);
46 __ Bl(&entry); // Recursive call factorial_rec(n - 1).
47 __ Pop(lr, x1);
48 __ Mul(x0, x0, x1);
49 __ Ret();
50
51 __ Bind(&input_is_zero);
52 __ Mov(x0, 1);
53 __ Ret();
54 }
55
56
57 #ifndef TEST_EXAMPLES
58 #ifdef USE_SIMULATOR
main(void)59 int main(void) {
60 // Create and initialize the assembler and the simulator.
61 byte assm_buf[BUF_SIZE];
62 MacroAssembler masm(assm_buf, BUF_SIZE);
63 Decoder decoder;
64 Simulator simulator(&decoder);
65
66 // Generate the code for the example function.
67 Label factorial_rec;
68 masm.Bind(&factorial_rec);
69 GenerateFactorialRec(&masm);
70 masm.FinalizeCode();
71
72 // Run the example function.
73 uint64_t input_val = 16;
74 simulator.set_xreg(0, input_val);
75 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&factorial_rec));
76 printf("factorial(%ld) = %ld\n", input_val, simulator.xreg(0));
77
78 return 0;
79 }
80 #else
81 // Without the simulator there is nothing to test.
main(void)82 int main(void) { return 0; }
83 #endif // USE_SIMULATOR
84 #endif // TEST_EXAMPLES
85