Re: [flac-dev] How to check for 64-bit CPU?

2015-12-30 Thread Erik de Castro Lopo 
Thomas Zander wrote:

> I believe this is not portable. At least on my machine ("4.2.1
> Compatible FreeBSD Clang 3.4.1 (tags/RELEASE_34/dot1-final 208032)")

Its *is* detected and defined by autoconf at configure time.

Erik
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-30 Thread Erik de Castro Lopo 
LRN wrote:

> Guys, you do know that there are canned, portable autoconf macros for
> checking things like variable sizes at configuration/compilation time, right?

Indeed!

Erik
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-30 Thread Brian Willoughby 
It seems that most compilers define some sort of architecture values, but 
they're not necessarily consistent across all compilers. I believe that the 
original point of the FLAC__CPU_X86_64 and similar defines was to make these 
consistent within the FLAC sources, but not to reinvent the wheel entirely.

As others have pointed out, there are autoconf solutions for architecture 
detection, and it would make sense to leverage these and set FLAC__CPU_X86_64 
and related defines in the headers based on config.

Don't forget cross-compiling. Sometimes a developer wants to build for a 
different architecture than the one running.

Brian


On Dec 28, 2015, at 11:35 AM, lvqcl  wrote:
> In stream_encoder.c there's the following code:
> 
>  #if defined FLAC__CPU_X86_64 /* and other 64-bit arch, too */
>  if(mean <= 0x8000/512) { /* 512: more or less optimal for both 16- 
> and 24-bit input */
>  #else
>  if(mean <= 0x8000/8) { /* 32-bit arch: use 32-bit math if possible */
>  #endif
> 
> A) How to properly check for 64-bit architectures?
> I can check for "defined FLAC__CPU_X86_64" or "defined _WIN64".
> Is it possible to use SIZEOF_VOIDP? such as "#if SIZEOF_VOIDP == 8" ?
> 
> B) Does it make sense to put the following code into some header file?
> (if yes, what header file should be used?)
> 
> 
>  #if (defined FLAC__CPU_X86_64) || ...something else here...
>  #define FLAC__64BIT_ARCH 1
>  #else
>  #undef FLAC__64BIT_ARCH
>  #endif
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-30 Thread Thomas Zander 
On 29 December 2015 at 08:08, Erik de Castro Lopo  wrote:

> I would suggest:
>
>#if SIZEOF_VOIDP == 8

I believe this is not portable. At least on my machine ("4.2.1
Compatible FreeBSD Clang 3.4.1 (tags/RELEASE_34/dot1-final 208032)")
it's not defined. Probably this one comes closest:
#define __SIZEOF_POINTER__ 8

Riggs
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-30 Thread LRN 
On 30.12.2015 13:57, Thomas Zander wrote:
> On 29 December 2015 at 08:08, Erik de Castro Lopo wrote:
> 
>> I would suggest:
>>
>>#if SIZEOF_VOIDP == 8
> 
> I believe this is not portable. At least on my machine ("4.2.1
> Compatible FreeBSD Clang 3.4.1 (tags/RELEASE_34/dot1-final 208032)")
> it's not defined. Probably this one comes closest:
> #define __SIZEOF_POINTER__ 8
> 

Guys, you do know that there are canned, portable autoconf macros for
checking things like variable sizes at configuration/compilation time, right?

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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Rafaël Carré 
Le 29 déc. 2015 20:31, "Erik de Castro Lopo"  a
écrit :
>
> Rafaël Carré wrote:
>
> > That would need a special case for Linux x32 which is x86_64 with 32
> > bits pointers
>
> It won't be wrong for x32, just sub-optimal.
>
> Please feel free to suggest a way to detect x32.

>From https://sourceware.org/glibc/wiki/x32

x86-64 C/C++ compiler predefines macro__LP64__ while x32 C/C++ compiler
predefines macro __ILP32__.
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Dave Yeo 
On 12/29/15 11:31 AM, Erik de Castro Lopo wrote:
> Rafaël Carré wrote:
>
>> That would need a special case for Linux x32 which is x86_64 with 32
>> bits pointers
>
> It won't be wrong for x32, just sub-optimal.
>
> Please feel free to suggest a way to detect x32.
>

Shouldn't these tests be in configure and at worst x32 can be passed as 
target.
Dave
>
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Erik de Castro Lopo 
Rafaël Carré wrote:

> That would need a special case for Linux x32 which is x86_64 with 32
> bits pointers

It won't be wrong for x32, just sub-optimal.

Please feel free to suggest a way to detect x32.

Erik
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Erik de Castro Lopo 
Rafaël Carré wrote:

> From https://sourceware.org/glibc/wiki/x32
> 
> x86-64 C/C++ compiler predefines macro__LP64__ while x32 C/C++ compiler
> predefines macro __ILP32__.

What compiler defines these? GCC? Clang? The Intel compiler?

Erik
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Erik de Castro Lopo 
Dave Yeo wrote:

> Shouldn't these tests be in configure and at worst x32 can be passed as 
> target.

Indeed!

Erik
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Rafaël Carré 
On 12/28/2015 08:35 PM, lvqcl wrote:
> In stream_encoder.c there's the following code:
> 
>   #if defined FLAC__CPU_X86_64 /* and other 64-bit arch, too */
>   if(mean <= 0x8000/512) { /* 512: more or less optimal for both 16- 
> and 24-bit input */
>   #else
>   if(mean <= 0x8000/8) { /* 32-bit arch: use 32-bit math if possible 
> */
>   #endif
> 
> A) How to properly check for 64-bit architectures?
> I can check for "defined FLAC__CPU_X86_64" or "defined _WIN64".
> Is it possible to use SIZEOF_VOIDP? such as "#if SIZEOF_VOIDP == 8" ?

That would need a special case for Linux x32 which is x86_64 with 32
bits pointers
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-29 Thread Thomas Zander 
On 29 December 2015 at 13:33, Rafaël Carré  wrote:
> On 12/28/2015 08:35 PM, lvqcl wrote:
>> In stream_encoder.c there's the following code:
>>
>>   #if defined FLAC__CPU_X86_64 /* and other 64-bit arch, too */
>>   if(mean <= 0x8000/512) { /* 512: more or less optimal for both 16- 
>> and 24-bit input */
>>   #else
>>   if(mean <= 0x8000/8) { /* 32-bit arch: use 32-bit math if possible 
>> */
>>   #endif
>>
>> A) How to properly check for 64-bit architectures?
>> I can check for "defined FLAC__CPU_X86_64" or "defined _WIN64".
>> Is it possible to use SIZEOF_VOIDP? such as "#if SIZEOF_VOIDP == 8" ?
>
> That would need a special case for Linux x32 which is x86_64 with 32
> bits pointers

... and this probably won't be the last time we'd need to handle special cases.
Do we really need to handle this at all? Entangling CPU-arch-dependent
#ifdefs with input sample size (see "tuned for N-bit input" a few
lines below" seems weird.
IMHO finding the rice parameter should be independent of the cpu arch
unless there is a spectacular benefit by distinguishing.

Best regards
Riggs
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Re: [flac-dev] How to check for 64-bit CPU?

2015-12-28 Thread Erik de Castro Lopo 
lvqcl wrote:

> A) How to properly check for 64-bit architectures?
> I can check for "defined FLAC__CPU_X86_64" or "defined _WIN64".

Eww :)

> Is it possible to use SIZEOF_VOIDP? such as "#if SIZEOF_VOIDP == 8" ?

That would work.
 
> B) Does it make sense to put the following code into some header file?
> (if yes, what header file should be used?)
> 
> 
>   #if (defined FLAC__CPU_X86_64) || ...something else here...
>   #define FLAC__64BIT_ARCH 1
>   #else
>   #undef FLAC__64BIT_ARCH
>   #endif

I would suggest:

   #if SIZEOF_VOIDP == 8
   #define FLAC__64BIT_ARCH 1
   #else
   #define FLAC__64BIT_ARCH 0
   #endif

Setting a #define to either `0` or `1` means that it can be used in code like

   if (FLAC__64BIT_ARCH) {
   // 64 bit code
   } else {
   // 32 bit code
   }

and the compiler will syntax/type check both branches but optimises one
away completely.

Erik
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