Re: Using __int128 on 64-bit architectures

2013-04-21 Thread Michael Cree
On Sun, Apr 21, 2013 at 07:35:31PM +1000, Stephen Rothwell wrote: > On Sun, 21 Apr 2013 05:29:28 +0100 (BST) "Maciej W. Rozycki" > wrote: > > > > Hmm, nobody has replied, so just FYI such widening multiplication is > > available in all 64-bit MIPS hardware and GCC has supported it since 4.4 >

Re: Using __int128 on 64-bit architectures

2013-04-21 Thread Stephen Rothwell
On Sun, 21 Apr 2013 05:29:28 +0100 (BST) "Maciej W. Rozycki" wrote: > > Hmm, nobody has replied, so just FYI such widening multiplication is > available in all 64-bit MIPS hardware and GCC has supported it since 4.4 > or mid 2008 (older versions used a libgcc __multi3 helper, not quite so > e

Re: Using __int128 on 64-bit architectures

2013-04-20 Thread Maciej W. Rozycki
On Sun, 17 Mar 2013, H. Peter Anvin wrote: > How desirable/portable is it to use __int128 on non-x86 64-bit > architectures to get a 64*64 -> 128 bit multiply? On x86-64 this works > extremely well, but I'm worried about that needlessly breaking on other > architectures. Hmm, nobody has replied

Using __int128 on 64-bit architectures

2013-03-17 Thread H. Peter Anvin
Hi all, How desirable/portable is it to use __int128 on non-x86 64-bit architectures to get a 64*64 -> 128 bit multiply? On x86-64 this works extremely well, but I'm worried about that needlessly breaking on other architectures. In particular, it looks opportune to use a scaling-by-multiply inst