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[Guile-commits] 02/02: Optimize logand against a positive inum
From: |
Andy Wingo |
Subject: |
[Guile-commits] 02/02: Optimize logand against a positive inum |
Date: |
Mon, 10 Jan 2022 05:57:09 -0500 (EST) |
wingo pushed a commit to branch wip-inline-digits
in repository guile.
commit e90d543e7c535db10624288939720268826a9c6f
Author: Andy Wingo <wingo@pobox.com>
AuthorDate: Mon Jan 10 11:56:13 2022 +0100
Optimize logand against a positive inum
* libguile/integers.c (scm_integer_logand_zi): Optimize.
---
libguile/integers.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/libguile/integers.c b/libguile/integers.c
index a173d01f2..a1231a10d 100644
--- a/libguile/integers.c
+++ b/libguile/integers.c
@@ -2119,6 +2119,18 @@ scm_integer_logand_zi (struct scm_bignum *x, scm_t_inum
y)
if (y == 0)
return SCM_INUM0;
+ if (y > 0)
+ {
+ mp_limb_t rd = bignum_limbs (x)[0];
+ mp_limb_t yd = y;
+ if (bignum_is_negative (x))
+ rd = ~rd + 1;
+ scm_remember_upto_here_1 (x);
+ rd &= yd;
+ // Result must be a positive inum.
+ return SCM_I_MAKINUM (rd);
+ }
+
mpz_t result, zx, zy;
mpz_init (result);
alias_bignum_to_mpz (x, zx);