mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-05-08 10:50:21 +02:00
Code Activity

Implement a correct generation of Fibonacci numbers.

Browse source 
* doc/body.texi: Change documentation to no longer say
	it is a variant of the Fibonacci sequence, and document
	a proper implementation.
	Thanks to Jon Arintok for pointing out that the Fibonacci
	sequence generation was incorrect. It was documented, but
	still confusing.

	* check/fib.tst, check/fib.ok, check/bp.tst, check/bp.ok,
	doc/ifib.c, doc/rbif.c: Implement a proper Fibonacci
	sequence implementation.
This commit is contained in:
Paulo Andrade 2015-11-30 15:32:48 -02:00
parent fd57359498
commit 76876dd7bf
9 changed files with 80 additions and 65 deletions
Download patch file Download diff file Expand all files Collapse all files

16
doc/rfib.c
View file

@ -12,6 +12,7 @@ int main(int argc, char *argv[])
jit_node_t *call;
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 */
init_jit(argv[0]);
_jit = jit_new_state();
@ -19,8 +20,11 @@ int main(int argc, char *argv[])
label = jit_label();
jit_prolog ();
in = jit_arg ();
jit_getarg (JIT_V0, in); /* V0 = n */
ref = jit_blti (JIT_V0, 2);
jit_getarg (JIT_R0, in); /* R0 = n */
zero = jit_beqi (JIT_R0, 0);
jit_movr (JIT_V0, JIT_R0); /* V0 = R0 */
jit_movi (JIT_R0, 1);
ref = jit_blei (JIT_V0, 2);
jit_subi (JIT_V1, JIT_V0, 1); /* V1 = n-1 */
jit_subi (JIT_V2, JIT_V0, 2); /* V2 = n-2 */
jit_prepare();
@ -32,13 +36,11 @@ int main(int argc, char *argv[])
jit_pushargr(JIT_V2);
call = jit_finishi(NULL);
jit_patch_at(call, label);
jit_retval(JIT_V2); /* V2 = fib(n-2) */
jit_addi(JIT_V1, JIT_V1, 1);
jit_addr(JIT_R0, JIT_V1, JIT_V2); /* R0 = V1 + V2 + 1 */
jit_retr(JIT_R0);
jit_retval(JIT_R0); /* R0 = fib(n-2) */
jit_addr(JIT_R0, JIT_R0, JIT_V1); /* R0 = R0 + V1 */
jit_patch(ref); /* patch jump */
jit_movi(JIT_R0, 1); /* R0 = 1 */
jit_patch(zero); /* patch jump */
jit_retr(JIT_R0);
/* call the generated code, passing 32 as an argument */