On Wed, 9 May 2012, Daniel Marschall wrote:
I could sucessfully do a benchmark of my code. I found out that the
no-typecast-version (imull+movslq) needed 47 secs for 12 working packages,
while the typecast-version (imulq) needed only 38 secs per 12 working
packages. That is incredible!
Maybe
Am 09.05.2012 20:30, schrieb Ian Lance Taylor:
Daniel Marschall writes:
I did understand that the compiler used "signed" multiplication
instead of an unsigned one because char*char needs to be extended.
Maybe I am wrong, but couldn't the compiler "know" that the result
will be at least unsig
Am 09.05.2012 21:48, schrieb Marc Glisse:
On Wed, 9 May 2012, Daniel Marschall wrote:
1. I do not know my DisplayName/DisplayFamily (0f_2h or 0f_3h?).
Ask your processor (cpuid). Or your kernel (/proc/cpuinfo on linux).
/proc/cpuinfo says:
processor : 0
vendor_id : GenuineIntel
On Wed, 9 May 2012, Daniel Marschall wrote:
1. I do not know my DisplayName/DisplayFamily (0f_2h or 0f_3h?).
Ask your processor (cpuid). Or your kernel (/proc/cpuinfo on linux).
3. Should I compare Latency or Throughput if I want to produce fast code? Or
doesn't it matter which value I compa
Hello,
Look for the Intel Optimization Manual on intel.com. The appendixes
have latency and throughput information for the instruction set on
various Intel processors.
Uh-oh, that's hard. I tried to find the information, but I did only
found a part of the informations I was looking for.
Fi
Daniel Marschall writes:
> I did understand that the compiler used "signed" multiplication
> instead of an unsigned one because char*char needs to be extended.
>
> Maybe I am wrong, but couldn't the compiler "know" that the result
> will be at least unsigned because unsigned * unsigned = unsigned
Hello and thanks for your quick reply!
Am 09.05.2012 15:59, schrieb Ian Lance Taylor:
Note that the current GCC release is 4.7.0.
The problem with Debian Squeeze is always that I have to use "medieval"
software... ;-) Maybe I should develop the server software on a local
box using "unstab
Daniel Marschall writes:
> As I was optimizing my program, I found a few things which looked odd
> to me in the assembler code.
Thanks. It's often best to report missed optimizations at
http://gcc.gnu.org/bugzilla/ . They will tend to be forgotten on the
mailing list.
> I am on an AMD x64_32
