Re: Release D 2.071.1
On 06/28/2016 10:47 PM, deadalnix wrote: On Monday, 27 June 2016 at 23:26:25 UTC, Jack Stouffer wrote: [...] I wouldn't call 1.0 * -1.0 == 1.0 boring! What is this about ? https://issues.dlang.org/show_bug.cgi?id=16027
Re: Release D 2.071.1
On Monday, 27 June 2016 at 23:26:25 UTC, Jack Stouffer wrote: On Monday, 27 June 2016 at 23:15:06 UTC, Robert burner Schadek wrote: Awesome, releases are becoming more and more boring. I like it! I wouldn't call 1.0 * -1.0 == 1.0 boring! What is this about ?
Re: 4x faster strlen with 4 char sentinel
On Tuesday, 28 June 2016 at 09:18:34 UTC, qznc wrote:
Did you also compare to strlen from libc? I'd guess GNU libc
uses a lot more tricks like vector instructions.
I did test with the libc strlen, although the D libraries did not
have a strlen for dchar or wchar. I'm currently using this for
comparison, and playing around with shorter string lengths:
nothrow pure size_t strlen(const(char)* c) {
if (c is null )
return 0;
const(char)* c_save = c;
while (*c) {
c++;
}
return c - c_save;
}
I'm also trying some tests on a PA device where I have tools to
look at cache hits, misses, branches mispredicted. Similar C
code.
Re: [Semi OT] About code review
On 6/26/16 8:01 PM, deadalnix wrote: Several people during DConf asked abut tips and tricks on code review. So I wrote an article about it: http://www.deadalnix.me/2016/06/27/on-code-review/ Nice work. Let's see: https://www.reddit.com/r/programming/comments/4q9fl5/on_code_review/ -- Andrei
Re: 4x faster strlen with 4 char sentinel
On Tuesday, 28 June 2016 at 09:31:46 UTC, Sebastiaan Koppe wrote: If we were in interview, I'd ask you "what does this returns if you pass it an empty string ?" Since no one is answering: It depends on the memory right before c. But if there is at least one 0 right before it - which is quite likely - then you get some crazy big number returned. Yes, the test checked for 0 length but not with a preceding 0. I posted the fix. if (c is null || *c==0)
Re: Release D 2.071.1
On Monday, 27 June 2016 at 23:26:25 UTC, Jack Stouffer wrote: On Monday, 27 June 2016 at 23:15:06 UTC, Robert burner Schadek wrote: Awesome, releases are becoming more and more boring. I like it! I wouldn't call 1.0 * -1.0 == 1.0 boring! Yeah I was thinking this haha.
IUP, CD, IM, lua interfaces in D.
Now IUP library collections' interfaces accomplished. IUP(3.18): http://code.dlang.org/packages/iupd IM(3.10): http://code.dlang.org/packages/imd CD(5.9):http://code.dlang.org/packages/cdd lua(5.3.3): http://code.dlang.org/packages/nluad As I'm not good enough, all bindings may have many issues. Help me please. All bindings do not have cpp interface conversions in D. But these will be the next works.
Re: 4x faster strlen with 4 char sentinel
On Tuesday, 28 June 2016 at 01:53:22 UTC, deadalnix wrote:
On Sunday, 26 June 2016 at 16:40:08 UTC, Jay Norwood wrote:
After watching Andre's sentinel thing, I'm playing with strlen
on char strings with 4 terminating 0s instead of a single one.
Seems to work and is 4x faster compared to the runtime
version.
nothrow pure size_t strlen2(const(char)* c) {
if (c is null)
return 0;
size_t l=0;
while (*c){ c+=4; l+=4;}
while (*c==0){ c--; l--;}
return l+1;
}
This is the timing of my test case, which I can post if anyone
is interested.
strlen\Release>strlen
2738
681
If we were in interview, I'd ask you "what does this returns if
you pass it an empty string ?"
Since no one is answering:
It depends on the memory right before c. But if there is at least
one 0 right before it - which is quite likely - then you get some
crazy big number returned.
Re: 4x faster strlen with 4 char sentinel
On Sunday, 26 June 2016 at 16:40:08 UTC, Jay Norwood wrote:
After watching Andre's sentinel thing, I'm playing with strlen
on char strings with 4 terminating 0s instead of a single one.
Seems to work and is 4x faster compared to the runtime version.
nothrow pure size_t strlen2(const(char)* c) {
if (c is null)
return 0;
size_t l=0;
while (*c){ c+=4; l+=4;}
while (*c==0){ c--; l--;}
return l+1;
}
This is the timing of my test case, which I can post if anyone
is interested.
strlen\Release>strlen
2738
681
Did you also compare to strlen from libc? I'd guess GNU libc uses
a lot more tricks like vector instructions.
Re: Release D 2.071.1
On 6/27/2016 3:11 PM, Martin Nowak wrote: Glad to announce D 2.071.1. http://dlang.org/download.html This point release fixes a few issues over 2.071.0, see the changelog for more details. http://dlang.org/changelog/2.071.1.html -Martin Thank you, Martin!
Re: 4x faster strlen with 4 char sentinel
On Tuesday, 28 June 2016 at 03:11:26 UTC, Jay Norwood wrote:
On Tuesday, 28 June 2016 at 01:53:22 UTC, deadalnix wrote:
If we were in interview, I'd ask you "what does this returns
if you pass it an empty string ?"
I'd say use this one instead, to avoid negative size_t. It is
also a little faster for the same measurement.
nothrow pure size_t strlen2(const(char)* c) {
if (c is null)
return 0;
const(char)* c_save = c;
while (*c){ c+=4; }
while (*c==0){ c--; }
c++;
return c - c_save;
}
2738
540
2744
If we were in an interview, I would insist.
