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guile/libguile/lightning/doc/ifib.c
Andy Wingo 40aafa5279 Merge GNU lightning to libguile/lightning
* libguile/lightning/: New directory, made by the following commands:

  git remote add lightning https://git.savannah.gnu.org/git/lightning.git
  git merge -s ours --no-commit --allow-unrelated-histories lightning/master
  git read-tree --prefix=libguile/lightning/ -u lightning/master

  In theory we will be able to update via:

  git merge -s subtree lightning/master
2018-06-30 10:54:39 +02:00

49 lines
1.6 KiB
C

#include <stdio.h>
#include <lightning.h>
static jit_state_t *_jit;
typedef int (*pifi)(int); /* Pointer to Int Function of Int */
int main(int argc, char *argv[])
{
pifi fib;
jit_node_t *in; /* offset of the argument */
jit_node_t *ref; /* to patch the forward reference */
jit_node_t *zero; /* to patch the forward reference */
jit_node_t *jump; /* jump to start of loop */
jit_node_t *loop; /* start of the loop */
init_jit(argv[0]);
_jit = jit_new_state();
jit_prolog ();
in = jit_arg ();
jit_getarg (JIT_R0, in); /* R0 = n */
zero = jit_beqi (JIT_R0, 0);
jit_movr (JIT_R1, JIT_R0);
jit_movi (JIT_R0, 1);
ref = jit_blei (JIT_R1, 2);
jit_subi (JIT_R2, JIT_R1, 2);
jit_movr (JIT_R1, JIT_R0);
loop= jit_label();
jit_subi (JIT_R2, JIT_R2, 1); /* decr. counter */
jit_movr (JIT_V0, JIT_R0); /* V0 = R0 */
jit_addr (JIT_R0, JIT_R0, JIT_R1); /* R0 = R0 + R1 */
jit_movr (JIT_R1, JIT_V0); /* R1 = V0 */
jump= jit_bnei (JIT_R2, 0); /* if (R2) goto loop; */
jit_patch_at(jump, loop);
jit_patch(ref); /* patch forward jump */
jit_patch(zero); /* patch forward jump */
jit_retr (JIT_R0);
/* call the generated code, passing 36 as an argument */
fib = jit_emit();
jit_clear_state();
printf("fib(%d) = %d\n", 36, fib(36));
jit_destroy_state();
finish_jit();
return 0;
}