SDL_cpuinfo.h File Reference

#include "SDL_stdinc.h"
#include "begin_code.h"
#include "close_code.h"

Go to the source code of this file.

Macros
#define	SDL_CACHELINE_SIZE   128

Functions
DECLSPEC int SDLCALL	SDL_GetCPUCount (void)
DECLSPEC int SDLCALL	SDL_GetCPUCacheLineSize (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasRDTSC (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasAltiVec (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasMMX (void)
DECLSPEC SDL_bool SDLCALL	SDL_Has3DNow (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasSSE (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasSSE2 (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasSSE3 (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasSSE41 (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasSSE42 (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasAVX (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasAVX2 (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasAVX512F (void)
DECLSPEC SDL_bool SDLCALL	SDL_HasNEON (void)
DECLSPEC int SDLCALL	SDL_GetSystemRAM (void)
DECLSPEC size_t SDLCALL	SDL_SIMDGetAlignment (void)
	Report the alignment this system needs for SIMD allocations. More...
DECLSPEC void *SDLCALL	SDL_SIMDAlloc (const size_t len)
	Allocate memory in a SIMD-friendly way. More...
DECLSPEC void SDLCALL	SDL_SIMDFree (void *ptr)
	Deallocate memory obtained from SDL_SIMDAlloc. More...

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 114 of file SDL_cpuinfo.h.

Function Documentation

SDL_GetCPUCacheLineSize()

DECLSPEC int SDLCALL SDL_GetCPUCacheLineSize

(

void

)

This function returns the L1 cache line size of the CPU

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

SDL_GetCPUCount()

DECLSPEC int SDLCALL SDL_GetCPUCount

(

void

)

This function returns the number of CPU cores available.

SDL_GetSystemRAM()

DECLSPEC int SDLCALL SDL_GetSystemRAM

(

void

)

This function returns the amount of RAM configured in the system, in MB.

SDL_Has3DNow()

DECLSPEC SDL_bool SDLCALL SDL_Has3DNow

(

void

)

This function returns true if the CPU has 3DNow! features.

SDL_HasAltiVec()

DECLSPEC SDL_bool SDLCALL SDL_HasAltiVec

(

void

)

This function returns true if the CPU has AltiVec features.

SDL_HasAVX()

DECLSPEC SDL_bool SDLCALL SDL_HasAVX

(

void

)

This function returns true if the CPU has AVX features.

SDL_HasAVX2()

DECLSPEC SDL_bool SDLCALL SDL_HasAVX2

(

void

)

This function returns true if the CPU has AVX2 features.

SDL_HasAVX512F()

DECLSPEC SDL_bool SDLCALL SDL_HasAVX512F

(

void

)

This function returns true if the CPU has AVX-512F (foundation) features.

SDL_HasMMX()

DECLSPEC SDL_bool SDLCALL SDL_HasMMX

(

void

)

This function returns true if the CPU has MMX features.

SDL_HasNEON()

DECLSPEC SDL_bool SDLCALL SDL_HasNEON

(

void

)

This function returns true if the CPU has NEON (ARM SIMD) features.

SDL_HasRDTSC()

DECLSPEC SDL_bool SDLCALL SDL_HasRDTSC

(

void

)

This function returns true if the CPU has the RDTSC instruction.

SDL_HasSSE()

DECLSPEC SDL_bool SDLCALL SDL_HasSSE

(

void

)

This function returns true if the CPU has SSE features.

SDL_HasSSE2()

DECLSPEC SDL_bool SDLCALL SDL_HasSSE2

(

void

)

This function returns true if the CPU has SSE2 features.

SDL_HasSSE3()

DECLSPEC SDL_bool SDLCALL SDL_HasSSE3

(

void

)

This function returns true if the CPU has SSE3 features.

SDL_HasSSE41()

DECLSPEC SDL_bool SDLCALL SDL_HasSSE41

(

void

)

This function returns true if the CPU has SSE4.1 features.

SDL_HasSSE42()

DECLSPEC SDL_bool SDLCALL SDL_HasSSE42

(

void

)

This function returns true if the CPU has SSE4.2 features.

SDL_SIMDAlloc()

DECLSPEC void* SDLCALL 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 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.

Parameters

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

Returns

Pointer to newly-allocated block, NULL if out of memory.

See also

SDL_SIMDAlignment

SDL_SIMDFree

SDL_SIMDFree()

DECLSPEC void SDLCALL 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(). It can't be used on pointers from malloc, realloc, SDL_malloc, memalign, new[], etc.

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

See also

SDL_SIMDAlloc

SDL_SIMDGetAlignment()

DECLSPEC size_t SDLCALL 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.