From 3e3b44d087ab616089402129b2bc4c4831c6b33a Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Wed, 16 Mar 2016 14:30:29 +0100 Subject: Optimise zsqr, zmul, zstr, zdivmod, zpow, and zpowu MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- src/zpowu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'src/zpowu.c') diff --git a/src/zpowu.c b/src/zpowu.c index c4a2a64..cf879e0 100644 --- a/src/zpowu.c +++ b/src/zpowu.c @@ -4,9 +4,14 @@ #define tb libzahl_tmp_pow_b +extern void zmul_impl(z_t a, z_t b, z_t c); +extern void zsqr_impl(z_t a, z_t b); + void zpowu(z_t a, z_t b, unsigned long long int c) { + int neg; + if (unlikely(!c)) { if (zzero(b)) libzahl_failure(-ZERROR_0_POW_0); @@ -17,12 +22,16 @@ zpowu(z_t a, z_t b, unsigned long long int c) return; } - zset(tb, b); + neg = znegative(b) && (c & 1); + zabs(tb, b); zsetu(a, 1); for (; c; c >>= 1) { if (c & 1) - zmul(a, a, tb); - zsqr(tb, tb); + zmul_impl(a, a, tb); + zsqr_impl(tb, tb); } + + if (neg) + zneg(a, a); } -- cgit v1.2.3-70-g09d2