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[pcsx_rearmed.git] / deps / lightning / doc / rfib.c
1 #include <stdio.h>
2 #include <lightning.h>
3
4 static jit_state_t *_jit;
5
6 typedef int (*pifi)(int);       /* Pointer to Int Function of Int */
7
8 int main(int argc, char *argv[])
9 {
10   pifi       fib;
11   jit_node_t *label;
12   jit_node_t *call;
13   jit_node_t *in;                 /* offset of the argument */
14   jit_node_t *ref;                /* to patch the forward reference */
15   jit_node_t *zero;             /* to patch the forward reference */
16
17   init_jit(argv[0]);
18   _jit = jit_new_state();
19
20   label = jit_label();
21         jit_prolog   ();
22   in =  jit_arg      ();
23         jit_getarg   (JIT_R0, in);              /* R0 = n */
24  zero = jit_beqi     (JIT_R0, 0);
25         jit_movr     (JIT_V0, JIT_R0);          /* V0 = R0 */
26         jit_movi     (JIT_R0, 1);
27   ref = jit_blei     (JIT_V0, 2);
28         jit_subi     (JIT_V1, JIT_V0, 1);       /* V1 = n-1 */
29         jit_subi     (JIT_V2, JIT_V0, 2);       /* V2 = n-2 */
30         jit_prepare();
31           jit_pushargr(JIT_V1);
32         call = jit_finishi(NULL);
33         jit_patch_at(call, label);
34         jit_retval(JIT_V1);                     /* V1 = fib(n-1) */
35         jit_prepare();
36           jit_pushargr(JIT_V2);
37         call = jit_finishi(NULL);
38         jit_patch_at(call, label);
39         jit_retval(JIT_R0);                     /* R0 = fib(n-2) */
40         jit_addr(JIT_R0, JIT_R0, JIT_V1);       /* R0 = R0 + V1 */
41
42   jit_patch(ref);                               /* patch jump */
43   jit_patch(zero);                              /* patch jump */
44         jit_retr(JIT_R0);
45
46   /* call the generated code, passing 32 as an argument */
47   fib = jit_emit();
48   jit_clear_state();
49   printf("fib(%d) = %d\n", 32, fib(32));
50   jit_destroy_state();
51   finish_jit();
52   return 0;
53 }