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SDL2-FFI-0.08
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/ SDL2::cpuinfo

NAME

SDL2::cpuinfo - CPU feature detection for SDL

SYNOPSIS

use SDL2 qw[:cpuinfo];

DESCRIPTION

SDL2::version represents the library's version as three levels: major, minor, and patch level.

Functions

These functions may be imported with the :cpuinfo tag.

SDL_GetCPUCount( )

Get the number of CPU cores available.

my $cores = SDL_GetCPUCount( );

Returns the total number of logical CPU cores. On CPUs that include technologies such as hyperthreading, the number of logical cores may be more than the number of physical cores.

SDL_GetCPUCacheLineSize( )

Determine the L1 cache line size of the CPU.

my $cache = SDL_GetCPUCacheLineSize( );

This is useful for determining multi-threaded structure padding or SIMD prefetch sizes.

Returns the L1 cache line size of the CPU, in bytes.

SDL_HasRDTSC( )

Determine whether the CPU has the RDTSC instruction.

my $rdtsc = SDL_HasRDTSC( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has the RDTSC instruction or SDL_FALSE if not.

SDL_HasAltiVec( )

Determine whether the CPU has AltiVec features.

my $altiVec = SDL_HasAltiVec( );

This always returns false on CPUs that aren't using PowerPC instruction sets.

Returns SDL_TRUE if the CPU has AltiVec features or SDL_FALSE if not.

SDL_HasMMX( )

Determine whether the CPU has MMX features.

my $mmx = SDL_HasMMX( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has MMX features or SDL_FALSE if not.

SDL_Has3DNow( )

Determine whether the CPU has 3DNow! features.

my $_3dnow = SDL_Has3DNow( );

This always returns false on CPUs that aren't using AMD instruction sets.

Returns SDL_TRUE if the CPU has 3DNow! features or SDL_FALSE if not.

SDL_HasSSE( )

Determine whether the CPU has SSE features.

my $sse = SDL_HasSSE( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has SSE features or SDL_FALSE if not.

SDL_HasSSE2( )

Determine whether the CPU has SSE2 features.

my $sse2 = SDL_HasSSE2( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has SSE2 features or SDL_FALSE if not.

SDL_HasSSE3( )

Determine whether the CPU has SSE3 features.

my $sse3 = SDL_HasSSE3( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has SSE3 features or SDL_FALSE if not.

SDL_HasSSE41( )

Determine whether the CPU has SSE4.1 features.

my $sse41 = SDL_HasSSE41( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has SSE4.1 features or SDL_FALSE if not.

SDL_HasSSE42( )

Determine whether the CPU has SSE4.2 features.

my $sse42 = SDL_HasSSE42( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has SSE4.2 features or SDL_FALSE if not.

SDL_HasAVX( )

Determine whether the CPU has AVX features.

my $avx = SDL_HasAVX( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has AVX features or SDL_FALSE if not.

SDL_HasAVX2( )

Determine whether the CPU has AVX2 features.

my $avx2 = SDL_HasAVX2( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has AVX2 features or SDL_FALSE if not.

SDL_HasAVX512F( )

Determine whether the CPU has AVX-512F (foundation) features.

my $avx512 = SDL_HasAVX512F( );

This always returns false on CPUs that aren't using Intel instruction sets.

Returns SDL_TRUE if the CPU has AVX-512F features or SDL_FALSE if not.

SDL_HasARMSIMD( )

Determine whether the CPU has ARM SIMD (ARMv6) features.

my $arm6 = SDL_HasARMSIMD( );

This is different from ARM NEON, which is a different instruction set.

This always returns false on CPUs that aren't using ARM instruction sets.

Returns SDL_TRUE if the CPU has ARM SIMD features or SDL_FALSE if not.

SDL_HasNEON( )

Determine whether the CPU has NEON (ARM SIMD) features.

my $neon = SDL_HasNEON( );

This always returns false on CPUs that aren't using ARM instruction sets.

Returns SDL_TRUE if the CPU has ARM NEON features or SDL_FALSE if not.

SDL_GetSystemRAM( )

Get the amount of RAM configured in the system.

my $mb = SDL_GetSystemRAM( );

Returns the amount of RAM configured in the system in MB.

SDL_SIMDGetAlignment( )

Report the alignment this system needs for SIMD allocations.

my $size = SDL_SIMDGetAlignment( );

This will return the minimum number of bytes to which a pointer must be aligned to be compatible with SIMD instructions on the current machine. For example, if the machine supports SSE only, it will return 16, but if it supports AVX-512F, it'll return 64 (etc). This only reports values for instruction sets SDL knows about, so if your SDL build doesn't have SDL_HasAVX512F( ), then it might return 16 for the SSE support it sees and not 64 for the AVX-512 instructions that exist but SDL doesn't know about. Plan accordingly.

Returns alignment in bytes needed for available, known SIMD instructions.

SDL_SIMDAlloc( ... )

Allocate memory in a SIMD-friendly way.

my $ptr = SDL_SIMDAlloc( 1024 * 64 );

This will allocate a block of memory that is suitable for use with SIMD instructions. Specifically, it will be properly aligned and padded for the system's supported vector instructions.

The memory returned will be padded such that it is safe to read or write an incomplete vector at the end of the memory block. This can be useful so you don't have to drop back to a scalar fallback at the end of your SIMD processing loop to deal with the final elements without overflowing the allocated buffer.

You must free this memory with SDL_SIMDFree( ), not SDL_free( ... ), undef, variable scope tricks, etc.

Note that SDL will only deal with SIMD instruction sets it is aware of; for example, SDL 2.0.8 knows that SSE wants 16-byte vectors (SDL_HasSSE( )), and AVX2 wants 32 bytes (SDL_HasAVX2( )), but doesn't know that AVX-512 wants 64. To be clear: if you can't decide to use an instruction set with an SDL_Has*( ) function, don't use that instruction set with memory allocated through here.

SDL_AllocSIMD( 0 ) will return a non-NULL pointer, assuming the system isn't out of memory, but you are not allowed to dereference it (because you only own zero bytes of that buffer).

Expected parameters include:

len - The length, in bytes, of the block to allocate. The actual allocated block might be larger due to padding, etc.

Returns a pointer to newly-allocated block, NULL if out of memory.

SDL_SIMDRealloc( ... )

Reallocate memory obtained from SDL_SIMDAlloc( ... ).

$ptr = SDL_SIMDRealloc( $ptr, 1024 * 32 );

It is not valid to use this function on a pointer from anything but SDL_SIMDAlloc( ... ). It can't be used on pointers from malloc, realloc, SDL_malloc( ... ), memalign, new, etc.

Expected parameters include:

mem - The pointer obtained from SDL_SIMDAlloc( ... ). This function also accepts NULL, at which point this function is the same as calling SDL_SIMDAlloc( ... ) with a NULL pointer.
len - The length, in bytes, of the block to allocated. The actual allocated block might be larger due to padding, etc. Passing 0 will return a non-NULL pointer, assuming the system isn't out of memory.

Returns a pointer to newly-reallocated block, NULL if out of memory.

SDL_SIMDFree( )

Deallocate memory obtained from SDL_SIMDAlloc( ... ).

SDL_SIMDFree( $ptr );

It is not valid to use this function on a pointer from anything but SDL_SIMDAlloc( ... ) or SDL_SIMDRealloc( ... ). It can't be used on pointers from malloc, realloc, SDL_malloc, memalign, new, etc.

However, SDL_SIMDFree( undef ) is a legal no-op.

The memory pointed to by ptr is no longer valid for access upon return, and may be returned to the system or reused by a future allocation. The pointer passed to this function is no longer safe to dereference once this function returns, and should be discarded.

Expected parameters include:

LICENSE

Copyright (C) Sanko Robinson.

This library is free software; you can redistribute it and/or modify it under the terms found in the Artistic License 2. Other copyrights, terms, and conditions may apply to data transmitted through this module.

AUTHOR

Sanko Robinson <sanko@cpan.org>