RE: from where comes "__moddi3"?

2007-07-21 Thread Arjan van de Ven
On Sat, 2007-07-21 at 14:27 -0700, David Schwartz wrote: > > On 7/21/07, Jan Engelhardt <[EMAIL PROTECTED]> wrote: > > > v & 0x0F <=> v % 16 > > Indeed. (Why would anyone want to mod/div by 15 anyway?). My bad. > > Actually, it's the compiler's bad. That's a pretty fundamental equivalence > tha

RE: from where comes "__moddi3"?

2007-07-21 Thread David Schwartz
> On 7/21/07, Jan Engelhardt <[EMAIL PROTECTED]> wrote: > > v & 0x0F <=> v % 16 > Indeed. (Why would anyone want to mod/div by 15 anyway?). My bad. Actually, it's the compiler's bad. That's a pretty fundamental equivalence that the compiler should recognize for native integral types. DS - T

Re: from where comes "__moddi3"?

2007-07-21 Thread Peter Zijlstra
On Sat, 2007-07-21 at 21:58 +0200, Jan-Benedict Glaw wrote: > On Sat, 2007-07-21 21:31:13 +0200, Peter Zijlstra <[EMAIL PROTECTED]> wrote: > > On Sat, 2007-07-21 at 15:21 -0400, Robert P. J. Day wrote: > > > > use do_div(). > > > > 16 works because gcc translates that into a right shift. > > Rig

Re: from where comes "__moddi3"?

2007-07-21 Thread Alexander Shishkin
On 7/21/07, Jan Engelhardt <[EMAIL PROTECTED]> wrote: v & 0x0F <=> v % 16 Indeed. (Why would anyone want to mod/div by 15 anyway?). My bad. Regards, -- Alex - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo i

Re: from where comes "__moddi3"?

2007-07-21 Thread Jan-Benedict Glaw
On Sat, 2007-07-21 21:31:13 +0200, Peter Zijlstra <[EMAIL PROTECTED]> wrote: > On Sat, 2007-07-21 at 15:21 -0400, Robert P. J. Day wrote: > > use do_div(). > > 16 works because gcc translates that into a right shift. Right shift? Doesn't it just mask out everything but the low 4 bit? MfG, JBG

Re: from where comes "__moddi3"?

2007-07-21 Thread Robert P. J. Day
" undefined! > > > > and, not surprisingly, when i try to insmod: > > > > insmod: error inserting 'seq.ko': -1 Unknown symbol in module > > > > (using 16 rather than 15 works fine, as i assume that the modulus > > call is simply replaced

Re: from where comes "__moddi3"?

2007-07-21 Thread Jan Engelhardt
On Jul 21 2007 23:33, Alexander Shishkin wrote: > On 7/21/07, Robert P. J. Day <[EMAIL PROTECTED]> wrote: >> >> again, probably displaying my abject ignorance, but i wrote a >> trivial module that tries to "var % 15", and i get: >> >> WARNING: "__moddi3" undefined! > ...which comes from libgcc

Re: from where comes "__moddi3"?

2007-07-21 Thread Alexander Shishkin
On 7/21/07, Robert P. J. Day <[EMAIL PROTECTED]> wrote: again, probably displaying my abject ignorance, but i wrote a trivial module that tries to "var % 15", and i get: WARNING: "__moddi3" undefined! ...which comes from libgcc1 which you obviously don't want to link against. Does (var &

Re: from where comes "__moddi3"?

2007-07-21 Thread Peter Zijlstra
insmod: > > insmod: error inserting 'seq.ko': -1 Unknown symbol in module > > (using 16 rather than 15 works fine, as i assume that the modulus > call is simply replaced by an optimized bitwise comparison.) > > so ... from where comes __moddi3? i know there are

from where comes "__moddi3"?

2007-07-21 Thread Robert P. J. Day
g 16 rather than 15 works fine, as i assume that the modulus call is simply replaced by an optimized bitwise comparison.) so ... from where comes __moddi3? i know there are places in the kernel source tree that do non-power-of-2 moduli, and they