From 112e4518f0d38fc3c52e55c7d7e77b66a295ec2b Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 5 Aug 2015 11:04:11 -0700 Subject: target-alpha: Special case cmpbge with zero Knowing the comparator is zero leads to a simpler operation. Signed-off-by: Richard Henderson --- target-alpha/int_helper.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'target-alpha/int_helper.c') diff --git a/target-alpha/int_helper.c b/target-alpha/int_helper.c index 4a6e95512b..d7f4774127 100644 --- a/target-alpha/int_helper.c +++ b/target-alpha/int_helper.c @@ -58,6 +58,20 @@ uint64_t helper_zap(uint64_t val, uint64_t mask) return helper_zapnot(val, ~mask); } +uint64_t helper_cmpbe0(uint64_t a) +{ + uint64_t m = 0x7f7f7f7f7f7f7f7fULL; + uint64_t c = ~(((a & m) + m) | a | m); + /* a.......b.......c.......d.......e.......f.......g.......h....... */ + c |= c << 7; + /* ab......bc......cd......de......ef......fg......gh......h....... */ + c |= c << 14; + /* abcd....bcde....cdef....defg....efgh....fgh.....gh......h....... */ + c |= c << 28; + /* abcdefghbcdefgh.cdefgh..defgh...efgh....fgh.....gh......h....... */ + return c >> 56; +} + uint64_t helper_cmpbge(uint64_t a, uint64_t b) { uint64_t mask = 0x00ff00ff00ff00ffULL; -- cgit 1.4.1