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)
 Report the alignment this system needs for SIMD allocations. More...
 
voidSDL_SIMDAlloc (const size_t len)
 Allocate memory in a SIMD-friendly way. More...
 
void 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()

int 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.

Definition at line 133 of file SDL_dynapi_procs.h.

References cpuid, d, SDL_CACHELINE_SIZE, SDL_GetCPUType(), SDL_strcmp, and void.

◆ SDL_GetCPUCount()

int SDL_GetCPUCount ( void  )

This function returns the number of CPU cores available.

Definition at line 548 of file SDL_cpuinfo.c.

549 {
550  if (!SDL_CPUCount) {
551 #ifndef SDL_CPUINFO_DISABLED
552 #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
553  if (SDL_CPUCount <= 0) {
554  SDL_CPUCount = (int)sysconf(_SC_NPROCESSORS_ONLN);
555  }
556 #endif
557 #ifdef HAVE_SYSCTLBYNAME
558  if (SDL_CPUCount <= 0) {
559  size_t size = sizeof(SDL_CPUCount);
560  sysctlbyname("hw.ncpu", &SDL_CPUCount, &size, NULL, 0);
561  }
562 #endif
563 #ifdef __WIN32__
564  if (SDL_CPUCount <= 0) {
565  SYSTEM_INFO info;
566  GetSystemInfo(&info);
567  SDL_CPUCount = info.dwNumberOfProcessors;
568  }
569 #endif
570 #ifdef __OS2__
571  if (SDL_CPUCount <= 0) {
572  DosQuerySysInfo(QSV_NUMPROCESSORS, QSV_NUMPROCESSORS,
573  &SDL_CPUCount, sizeof(SDL_CPUCount) );
574  }
575 #endif
576 #endif
577  /* There has to be at least 1, right? :) */
578  if (SDL_CPUCount <= 0) {
579  SDL_CPUCount = 1;
580  }
581  }
582  return SDL_CPUCount;
583 }

References NULL, and SDL_CPUCount.

◆ SDL_GetSystemRAM()

int SDL_GetSystemRAM ( void  )

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

Definition at line 143 of file SDL_dynapi_procs.h.

References NULL, and SDL_SystemRAM.

◆ SDL_Has3DNow()

SDL_bool SDL_Has3DNow ( void  )

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

Definition at line 137 of file SDL_dynapi_procs.h.

References CPU_FEATURE_AVAILABLE, and CPU_HAS_3DNOW.

◆ SDL_HasAltiVec()

SDL_bool SDL_HasAltiVec ( void  )

This function returns true if the CPU has AltiVec features.

Definition at line 135 of file SDL_dynapi_procs.h.

References CPU_FEATURE_AVAILABLE, and CPU_HAS_ALTIVEC.

◆ SDL_HasARMSIMD()

SDL_bool SDL_HasARMSIMD ( void  )

This function returns true if the CPU has ARM SIMD (ARMv6) features.

Definition at line 858 of file SDL_cpuinfo.c.

859 {
861 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_ARM_SIMD.

◆ SDL_HasAVX()

SDL_bool SDL_HasAVX ( void  )

This function returns true if the CPU has AVX features.

Definition at line 599 of file SDL_dynapi_procs.h.

References CPU_FEATURE_AVAILABLE, and CPU_HAS_AVX.

◆ SDL_HasAVX2()

SDL_bool SDL_HasAVX2 ( void  )

This function returns true if the CPU has AVX2 features.

Definition at line 846 of file SDL_cpuinfo.c.

847 {
849 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_AVX2.

◆ SDL_HasAVX512F()

SDL_bool SDL_HasAVX512F ( void  )

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

Definition at line 852 of file SDL_cpuinfo.c.

853 {
855 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_AVX512F.

◆ SDL_HasMMX()

SDL_bool SDL_HasMMX ( void  )

This function returns true if the CPU has MMX features.

Definition at line 798 of file SDL_cpuinfo.c.

799 {
801 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_MMX.

◆ SDL_HasNEON()

SDL_bool SDL_HasNEON ( void  )

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

Definition at line 652 of file SDL_dynapi_procs.h.

References CPU_FEATURE_AVAILABLE, and CPU_HAS_NEON.

◆ SDL_HasRDTSC()

SDL_bool SDL_HasRDTSC ( void  )

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

Definition at line 786 of file SDL_cpuinfo.c.

787 {
789 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_RDTSC.

◆ SDL_HasSSE()

SDL_bool SDL_HasSSE ( void  )

This function returns true if the CPU has SSE features.

Definition at line 810 of file SDL_cpuinfo.c.

811 {
813 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_SSE.

◆ SDL_HasSSE2()

SDL_bool SDL_HasSSE2 ( void  )

This function returns true if the CPU has SSE2 features.

Definition at line 139 of file SDL_dynapi_procs.h.

References CPU_FEATURE_AVAILABLE, and CPU_HAS_SSE2.

◆ SDL_HasSSE3()

SDL_bool SDL_HasSSE3 ( void  )

This function returns true if the CPU has SSE3 features.

Definition at line 822 of file SDL_cpuinfo.c.

823 {
825 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_SSE3.

◆ SDL_HasSSE41()

SDL_bool SDL_HasSSE41 ( void  )

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

Definition at line 141 of file SDL_dynapi_procs.h.

References CPU_FEATURE_AVAILABLE, and CPU_HAS_SSE41.

◆ SDL_HasSSE42()

SDL_bool SDL_HasSSE42 ( void  )

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

Definition at line 834 of file SDL_cpuinfo.c.

835 {
837 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_SSE42.

◆ 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 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
lenThe 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

Definition at line 943 of file SDL_cpuinfo.c.

944 {
945  const size_t alignment = SDL_SIMDGetAlignment();
946  const size_t padding = alignment - (len % alignment);
947  const size_t padded = (padding != alignment) ? (len + padding) : len;
948  Uint8 *retval = NULL;
949  Uint8 *ptr = (Uint8 *) SDL_malloc(padded + alignment + sizeof (void *));
950  if (ptr) {
951  /* store the actual malloc pointer right before our aligned pointer. */
952  retval = ptr + sizeof (void *);
953  retval += alignment - (((size_t) retval) % alignment);
954  *(((void **) retval) - 1) = ptr;
955  }
956  return retval;
957 }

References NULL, ptr, retval, SDL_malloc, and SDL_SIMDGetAlignment().

◆ 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(). 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

Definition at line 960 of file SDL_cpuinfo.c.

961 {
962  if (ptr) {
963  void **realptr = (void **) ptr;
964  realptr--;
965  SDL_free(*(((void **) ptr) - 1));
966  }
967 }

References ptr, and SDL_free.

◆ 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.

Definition at line 773 of file SDL_dynapi_procs.h.

References SDL_assert, SDL_GetCPUFeatures(), and SDL_SIMDAlignment.

Referenced by SDL_SIMDAlloc().

CPU_HAS_SSE
#define CPU_HAS_SSE
Definition: SDL_cpuinfo.c:102
NULL
#define NULL
Definition: begin_code.h:167
CPU_HAS_AVX2
#define CPU_HAS_AVX2
Definition: SDL_cpuinfo.c:108
CPU_FEATURE_AVAILABLE
#define CPU_FEATURE_AVAILABLE(f)
Definition: SDL_cpuinfo.c:784
CPU_HAS_SSE42
#define CPU_HAS_SSE42
Definition: SDL_cpuinfo.c:106
CPU_HAS_ARM_SIMD
#define CPU_HAS_ARM_SIMD
Definition: SDL_cpuinfo.c:111
len
GLenum GLsizei len
Definition: SDL_opengl_glext.h:2929
retval
SDL_bool retval
Definition: testgamecontroller.c:65
SDL_free
#define SDL_free
Definition: SDL_dynapi_overrides.h:377
CPU_HAS_RDTSC
#define CPU_HAS_RDTSC
Definition: SDL_cpuinfo.c:98
CPU_HAS_AVX512F
#define CPU_HAS_AVX512F
Definition: SDL_cpuinfo.c:110
size_t
unsigned int size_t
Definition: SDL_config_windows.h:68
SDL_SIMDGetAlignment
size_t SDL_SIMDGetAlignment(void)
Report the alignment this system needs for SIMD allocations.
Definition: SDL_cpuinfo.c:933
CPU_HAS_MMX
#define CPU_HAS_MMX
Definition: SDL_cpuinfo.c:100
size
GLsizeiptr size
Definition: SDL_opengl_glext.h:540
CPU_HAS_SSE3
#define CPU_HAS_SSE3
Definition: SDL_cpuinfo.c:104
SDL_malloc
#define SDL_malloc
Definition: SDL_dynapi_overrides.h:374
ptr
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Definition: pixman-arm-simd-asm.h:171
SDL_CPUCount
static int SDL_CPUCount
Definition: SDL_cpuinfo.c:545
Uint8
uint8_t Uint8
Definition: SDL_stdinc.h:179