motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-12-11 16:00:50 -07:00
Code Issues Projects Releases Packages Wiki Activity Actions

host-utils: Use __int128_t for mul[us]64

Browse source 
Replace some x86_64 specific inline assembly with something that
all 64-bit hosts ought to optimize well.  At worst this becomes
a call to the gcc __multi3 routine, which is no worse than our
implementation in util/host-utils.c.

With gcc 4.7, we get identical code generation for x86_64.  We
now get native multiplication on ia64 and s390x hosts.  With minor
improvements to gcc we can get it for ppc64 as well.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This commit is contained in:
Richard Henderson 2013-02-16 12:46:59 -08:00 • committed by Blue Swirl
parent be96bd3fbf
commit f540166b7d
3 changed files with 30 additions and 11 deletions
Download patch file Download diff file Expand all files Collapse all files

20
configure vendored
View file

@ -3150,6 +3150,22 @@ if compile_prog "" "" ; then
cpuid_h=yes
fi
########################################
# check if __[u]int128_t is usable.
int128=no
cat > $TMPC << EOF
__int128_t a;
__uint128_t b;
int main (void) {
a = a + b;
b = a * b;
return 0;
}
EOF
if compile_prog "" "" ; then
int128=yes
fi
##########################################
# End of CC checks
@ -3692,6 +3708,10 @@ if test "$cpuid_h" = "yes" ; then
echo "CONFIG_CPUID_H=y" >> $config_host_mak
fi
if test "$int128" = "yes" ; then
echo "CONFIG_INT128=y" >> $config_host_mak
fi
if test "$glusterfs" = "yes" ; then
echo "CONFIG_GLUSTERFS=y" >> $config_host_mak
fi