From 5ec8b6e78e08dbd645a3dceaf617bb0ad5b2c373 Mon Sep 17 00:00:00 2001 From: akr Date: Tue, 9 Jul 2013 15:43:48 +0000 Subject: * bignum.c (bary_mul): x*1 is x. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41869 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- bignum.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'bignum.c') diff --git a/bignum.c b/bignum.c index b25aebdcac..f2a61d1714 100644 --- a/bignum.c +++ b/bignum.c @@ -1856,6 +1856,17 @@ bary_mul(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yds, size_t yl, return; } + if (xl == 1 && xds[0] == 1) { + MEMCPY(zds, yds, BDIGIT, yl); + MEMZERO(zds + yl, BDIGIT, zl - yl); + return; + } + if (yl == 1 && yds[0] == 1) { + MEMCPY(zds, xds, BDIGIT, xl); + MEMZERO(zds + xl, BDIGIT, zl - xl); + return; + } + /* normal multiplication when x is small */ if (xl < KARATSUBA_MUL_DIGITS) { normal: -- cgit v1.2.3