Hi,
[auto build test ERROR on v4.6-rc5]
[cannot apply to next-20160519]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/zengzhaoxiu-163-com/lib-GCD-add-binary-GCD-algorithm/20160428-195527
Hi,
[auto build test ERROR on v4.6-rc5]
[cannot apply to next-20160519]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/zengzhaoxiu-163-com/lib-GCD-add-binary-GCD-algorithm/20160428-195527
> __ffs on the available architectures:
> Alpha: sometimes (CONFIG_ALPHA_EV6, CONFIG_ALPHA_EV67)
> ARC: sometimes (!CONFIG_ISA_ARCOMPACT)
> ARM: sometimes (V5+)
> ARM64: NO, could be written using RBIT and CLZ
> AVR: yes
> Blackfin: NO, could be written using
> __ffs on the available architectures:
> Alpha: sometimes (CONFIG_ALPHA_EV6, CONFIG_ALPHA_EV67)
> ARC: sometimes (!CONFIG_ISA_ARCOMPACT)
> ARM: sometimes (V5+)
> ARM64: NO, could be written using RBIT and CLZ
> AVR: yes
> Blackfin: NO, could be written using
> How does a CPU lack an efficient ffs/ctz anyway? There are all sorts
> of ways to implement it without a native insn, some of which are
> almost or just as fast as the native insn on cpus that have the
> latter. On anything with a fast multiply, the de Bruijn sequence
> approach is near-optimal,
> How does a CPU lack an efficient ffs/ctz anyway? There are all sorts
> of ways to implement it without a native insn, some of which are
> almost or just as fast as the native insn on cpus that have the
> latter. On anything with a fast multiply, the de Bruijn sequence
> approach is near-optimal,
On Thu, Apr 28, 2016 at 7:58 PM, Rich Felker wrote:
> On Thu, Apr 28, 2016 at 07:51:06PM +0200, Geert Uytterhoeven wrote:
>> On Thu, Apr 28, 2016 at 6:48 PM, George Spelvin wrote:
>> > Another few comments:
>> >
>> > 1. Would ARCH_HAS_FAST_FFS involve fewer
On Thu, Apr 28, 2016 at 7:58 PM, Rich Felker wrote:
> On Thu, Apr 28, 2016 at 07:51:06PM +0200, Geert Uytterhoeven wrote:
>> On Thu, Apr 28, 2016 at 6:48 PM, George Spelvin wrote:
>> > Another few comments:
>> >
>> > 1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
>>
On Thu, Apr 28, 2016 at 07:51:06PM +0200, Geert Uytterhoeven wrote:
> On Thu, Apr 28, 2016 at 6:48 PM, George Spelvin wrote:
> > Another few comments:
> >
> > 1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
>
> No, as you want to _disable_
On Thu, Apr 28, 2016 at 07:51:06PM +0200, Geert Uytterhoeven wrote:
> On Thu, Apr 28, 2016 at 6:48 PM, George Spelvin wrote:
> > Another few comments:
> >
> > 1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
>
> No, as you want to _disable_ ARCH_HAS_FAST_FFS / _enable_
On Thu, Apr 28, 2016 at 6:48 PM, George Spelvin wrote:
> Another few comments:
>
> 1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
No, as you want to _disable_ ARCH_HAS_FAST_FFS / _enable_
CPU_NO_EFFICIENT_FFS as soon as you're enabling support for
On Thu, Apr 28, 2016 at 6:48 PM, George Spelvin wrote:
> Another few comments:
>
> 1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
No, as you want to _disable_ ARCH_HAS_FAST_FFS / _enable_
CPU_NO_EFFICIENT_FFS as soon as you're enabling support for a
CPU that doesn't
On Thu, 2016-04-28 at 19:43 +0800, zengzhao...@163.com wrote:
> From: Zhaoxiu Zeng
>
> Because some architectures (alpha, armv6, etc.) don't provide
> hardware division, the mod operation is slow! Binary GCD algorithm
> uses simple arithmetic operations, it replaces
On Thu, 2016-04-28 at 19:43 +0800, zengzhao...@163.com wrote:
> From: Zhaoxiu Zeng
>
> Because some architectures (alpha, armv6, etc.) don't provide
> hardware division, the mod operation is slow! Binary GCD algorithm
> uses simple arithmetic operations, it replaces division with
> arithmetic
Another few comments:
1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
Rather than updating all the Kconfig files, it could be #defined in
the arch/*/asm/bitops.h files where the __ffs macro is defined. E.g.
diff --git a/arch/alpha/include/asm/bitops.h
Another few comments:
1. Would ARCH_HAS_FAST_FFS involve fewer changes than CPU_NO_EFFICIENT_FFS?
Rather than updating all the Kconfig files, it could be #defined in
the arch/*/asm/bitops.h files where the __ffs macro is defined. E.g.
diff --git a/arch/alpha/include/asm/bitops.h
On Apr 28, 2016, at 7:43 AM, zengzhao...@163.com wrote:
> + * This implements the binary GCD algorithm. (Often attributed to Stein,
> + * but as Knuth has noted, appears a first-century Chinese math text.)
Should this be "appears in a"?
Josh
On Apr 28, 2016, at 7:43 AM, zengzhao...@163.com wrote:
> + * This implements the binary GCD algorithm. (Often attributed to Stein,
> + * but as Knuth has noted, appears a first-century Chinese math text.)
Should this be "appears in a"?
Josh
Hi,
[auto build test ERROR on v4.6-rc5]
[cannot apply to next-20160428]
[if your patch is applied to the wrong git tree, please drop us a note to help
improving the system]
url:
https://github.com/0day-ci/linux/commits/zengzhaoxiu-163-com/lib-GCD-add-binary-GCD-algorithm/20160428-195527
Hi,
[auto build test ERROR on v4.6-rc5]
[cannot apply to next-20160428]
[if your patch is applied to the wrong git tree, please drop us a note to help
improving the system]
url:
https://github.com/0day-ci/linux/commits/zengzhaoxiu-163-com/lib-GCD-add-binary-GCD-algorithm/20160428-195527
From: Zhaoxiu Zeng
Because some architectures (alpha, armv6, etc.) don't provide hardware division,
the mod operation is slow! Binary GCD algorithm uses simple arithmetic
operations,
it replaces division with arithmetic shifts, comparisons, and subtractions.
I have
From: Zhaoxiu Zeng
Because some architectures (alpha, armv6, etc.) don't provide hardware division,
the mod operation is slow! Binary GCD algorithm uses simple arithmetic
operations,
it replaces division with arithmetic shifts, comparisons, and subtractions.
I have compiled successfully with
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