SDL  2.0
SDL_cpuinfo.h File Reference
#include "SDL_stdinc.h"
#include <immintrin.h>
#include "begin_code.h"
#include "close_code.h"
+ Include dependency graph for SDL_cpuinfo.h:
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Go to the source code of this file.

Macros

#define SDL_CACHELINE_SIZE   128
 

Functions

int SDL_GetCPUCount (void)
 
int SDL_GetCPUCacheLineSize (void)
 
SDL_bool SDL_HasRDTSC (void)
 
SDL_bool SDL_HasAltiVec (void)
 
SDL_bool SDL_HasMMX (void)
 
SDL_bool SDL_Has3DNow (void)
 
SDL_bool SDL_HasSSE (void)
 
SDL_bool SDL_HasSSE2 (void)
 
SDL_bool SDL_HasSSE3 (void)
 
SDL_bool SDL_HasSSE41 (void)
 
SDL_bool SDL_HasSSE42 (void)
 
SDL_bool SDL_HasAVX (void)
 
SDL_bool SDL_HasAVX2 (void)
 
SDL_bool SDL_HasAVX512F (void)
 
SDL_bool SDL_HasARMSIMD (void)
 
SDL_bool SDL_HasNEON (void)
 
int SDL_GetSystemRAM (void)
 
size_t SDL_SIMDGetAlignment (void)
 
void * SDL_SIMDAlloc (const size_t len)
 
void * SDL_SIMDRealloc (void *mem, const size_t len)
 
void SDL_SIMDFree (void *ptr)
 

Detailed Description

CPU feature detection for SDL.

Definition in file SDL_cpuinfo.h.

Macro Definition Documentation

◆ SDL_CACHELINE_SIZE

#define SDL_CACHELINE_SIZE   128

Definition at line 129 of file SDL_cpuinfo.h.

Function Documentation

◆ SDL_GetCPUCacheLineSize()

int SDL_GetCPUCacheLineSize ( void  )

Determine the L1 cache line size of the CPU.

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

Returns
the L1 cache line size of the CPU, in bytes.
Since
This function is available since SDL 2.0.0.

◆ SDL_GetCPUCount()

int SDL_GetCPUCount ( void  )

Get the number of CPU cores available.

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.
Since
This function is available since SDL 2.0.0.

◆ SDL_GetSystemRAM()

int SDL_GetSystemRAM ( void  )

Get the amount of RAM configured in the system.

Returns
the amount of RAM configured in the system in MB.
Since
This function is available since SDL 2.0.1.

◆ SDL_Has3DNow()

SDL_bool SDL_Has3DNow ( void  )

Determine whether the CPU has 3DNow! features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasAltiVec()

SDL_bool SDL_HasAltiVec ( void  )

Determine whether the CPU has AltiVec features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasARMSIMD()

SDL_bool SDL_HasARMSIMD ( void  )

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

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.
Since
This function is available since SDL 2.0.12.
See also
SDL_HasNEON

◆ SDL_HasAVX()

SDL_bool SDL_HasAVX ( void  )

Determine whether the CPU has AVX features.

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.
Since
This function is available since SDL 2.0.2.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasAVX2()

SDL_bool SDL_HasAVX2 ( void  )

Determine whether the CPU has AVX2 features.

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.
Since
This function is available since SDL 2.0.4.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasAVX512F()

SDL_bool SDL_HasAVX512F ( void  )

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

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.
Since
This function is available since SDL 2.0.9.
See also
SDL_HasAVX

◆ SDL_HasMMX()

SDL_bool SDL_HasMMX ( void  )

Determine whether the CPU has MMX features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasNEON()

SDL_bool SDL_HasNEON ( void  )

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

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.
Since
This function is available since SDL 2.0.6.

◆ SDL_HasRDTSC()

SDL_bool SDL_HasRDTSC ( void  )

Determine whether the CPU has the RDTSC instruction.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasSSE()

SDL_bool SDL_HasSSE ( void  )

Determine whether the CPU has SSE features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasSSE2()

SDL_bool SDL_HasSSE2 ( void  )

Determine whether the CPU has SSE2 features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE3
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasSSE3()

SDL_bool SDL_HasSSE3 ( void  )

Determine whether the CPU has SSE3 features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE41
SDL_HasSSE42

◆ SDL_HasSSE41()

SDL_bool SDL_HasSSE41 ( void  )

Determine whether the CPU has SSE4.1 features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE42

◆ SDL_HasSSE42()

SDL_bool SDL_HasSSE42 ( void  )

Determine whether the CPU has SSE4.2 features.

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.
Since
This function is available since SDL 2.0.0.
See also
SDL_Has3DNow
SDL_HasAltiVec
SDL_HasAVX
SDL_HasAVX2
SDL_HasMMX
SDL_HasRDTSC
SDL_HasSSE
SDL_HasSSE2
SDL_HasSSE3
SDL_HasSSE41

◆ SDL_SIMDAlloc()

void* SDL_SIMDAlloc ( const size_t  len)

Allocate memory in a SIMD-friendly way.

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_FreeSIMD(), not free() or SDL_free() or delete[], 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

  1. 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).

Parameters
lenThe length, in bytes, of the block to allocate. The actual allocated block might be larger due to padding, etc.
Returns
a pointer to the newly-allocated block, NULL if out of memory.
Since
This function is available since SDL 2.0.10.
See also
SDL_SIMDAlignment
SDL_SIMDRealloc
SDL_SIMDFree

◆ SDL_SIMDFree()

void SDL_SIMDFree ( void *  ptr)

Deallocate memory obtained from SDL_SIMDAlloc

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(NULL) 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.

Parameters
ptrThe pointer, returned from SDL_SIMDAlloc or SDL_SIMDRealloc, to deallocate. NULL is a legal no-op.
Since
This function is available since SDL 2.0.10.
See also
SDL_SIMDAlloc
SDL_SIMDRealloc

◆ SDL_SIMDGetAlignment()

size_t SDL_SIMDGetAlignment ( void  )

Report the alignment this system needs for SIMD allocations.

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
the alignment in bytes needed for available, known SIMD instructions.
Since
This function is available since SDL 2.0.10.

◆ SDL_SIMDRealloc()

void* SDL_SIMDRealloc ( void *  mem,
const size_t  len 
)

Reallocate memory obtained from SDL_SIMDAlloc

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.

Parameters
memThe 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.
lenThe 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 the newly-reallocated block, NULL if out of memory.
Since
This function is available since SDL 2.0.14.
See also
SDL_SIMDAlignment
SDL_SIMDAlloc
SDL_SIMDFree