1 // Copyright 2013, 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
main(void)58 int main(void) {
59 // Create and initialize the assembler and the simulator.
60 byte assm_buf[BUF_SIZE];
61 MacroAssembler masm(assm_buf, BUF_SIZE);
62 Decoder decoder;
63 Simulator simulator(&decoder);
64
65 // Generate the code for the example function.
66 Label factorial_rec;
67 masm.Bind(&factorial_rec);
68 GenerateFactorialRec(&masm);
69 masm.FinalizeCode();
70
71 // Run the example function.
72 uint64_t input_val = 16;
73 simulator.set_xreg(0, input_val);
74 simulator.RunFrom(factorial_rec.target());
75 printf("factorial(%ld) = %ld\n", input_val, simulator.xreg(0));
76
77 return 0;
78 }
79 #endif
80