SDL  2.0
SDL_cpuinfo.h File Reference
#include "SDL_stdinc.h"
#include <immintrin.h>
#include "begin_code.h"
#include "close_code.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_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 597 of file SDL_cpuinfo.c.

598 {
599  const char *cpuType = SDL_GetCPUType();
600  int a, b, c, d;
601  (void) a; (void) b; (void) c; (void) d;
602  if (SDL_strcmp(cpuType, "GenuineIntel") == 0) {
603  cpuid(0x00000001, a, b, c, d);
604  return (((b >> 8) & 0xff) * 8);
605  } else if (SDL_strcmp(cpuType, "AuthenticAMD") == 0) {
606  cpuid(0x80000005, a, b, c, d);
607  return (c & 0xff);
608  } else {
609  /* Just make a guess here... */
610  return SDL_CACHELINE_SIZE;
611  }
612 }

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 447 of file SDL_cpuinfo.c.

448 {
449  if (!SDL_CPUCount) {
450 #ifndef SDL_CPUINFO_DISABLED
451 #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
452  if (SDL_CPUCount <= 0) {
453  SDL_CPUCount = (int)sysconf(_SC_NPROCESSORS_ONLN);
454  }
455 #endif
456 #ifdef HAVE_SYSCTLBYNAME
457  if (SDL_CPUCount <= 0) {
458  size_t size = sizeof(SDL_CPUCount);
459  sysctlbyname("hw.ncpu", &SDL_CPUCount, &size, NULL, 0);
460  }
461 #endif
462 #ifdef __WIN32__
463  if (SDL_CPUCount <= 0) {
464  SYSTEM_INFO info;
465  GetSystemInfo(&info);
466  SDL_CPUCount = info.dwNumberOfProcessors;
467  }
468 #endif
469 #ifdef __OS2__
470  if (SDL_CPUCount <= 0) {
471  DosQuerySysInfo(QSV_NUMPROCESSORS, QSV_NUMPROCESSORS,
472  &SDL_CPUCount, sizeof(SDL_CPUCount) );
473  }
474 #endif
475 #endif
476  /* There has to be at least 1, right? :) */
477  if (SDL_CPUCount <= 0) {
478  SDL_CPUCount = 1;
479  }
480  }
481  return SDL_CPUCount;
482 }

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 761 of file SDL_cpuinfo.c.

762 {
763  if (!SDL_SystemRAM) {
764 #ifndef SDL_CPUINFO_DISABLED
765 #if defined(HAVE_SYSCONF) && defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
766  if (SDL_SystemRAM <= 0) {
767  SDL_SystemRAM = (int)((Sint64)sysconf(_SC_PHYS_PAGES) * sysconf(_SC_PAGESIZE) / (1024*1024));
768  }
769 #endif
770 #ifdef HAVE_SYSCTLBYNAME
771  if (SDL_SystemRAM <= 0) {
772 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__)
773 #ifdef HW_REALMEM
774  int mib[2] = {CTL_HW, HW_REALMEM};
775 #else
776  /* might only report up to 2 GiB */
777  int mib[2] = {CTL_HW, HW_PHYSMEM};
778 #endif /* HW_REALMEM */
779 #else
780  int mib[2] = {CTL_HW, HW_MEMSIZE};
781 #endif /* __FreeBSD__ || __FreeBSD_kernel__ */
782  Uint64 memsize = 0;
783  size_t len = sizeof(memsize);
784 
785  if (sysctl(mib, 2, &memsize, &len, NULL, 0) == 0) {
786  SDL_SystemRAM = (int)(memsize / (1024*1024));
787  }
788  }
789 #endif
790 #ifdef __WIN32__
791  if (SDL_SystemRAM <= 0) {
792  MEMORYSTATUSEX stat;
793  stat.dwLength = sizeof(stat);
794  if (GlobalMemoryStatusEx(&stat)) {
795  SDL_SystemRAM = (int)(stat.ullTotalPhys / (1024 * 1024));
796  }
797  }
798 #endif
799 #ifdef __OS2__
800  if (SDL_SystemRAM <= 0) {
801  Uint32 sysram = 0;
802  DosQuerySysInfo(QSV_TOTPHYSMEM, QSV_TOTPHYSMEM, &sysram, 4);
803  SDL_SystemRAM = (int) (sysram / 0x100000U);
804  }
805 #endif
806 #endif
807  }
808  return SDL_SystemRAM;
809 }

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 699 of file SDL_cpuinfo.c.

700 {
702 }

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 687 of file SDL_cpuinfo.c.

688 {
690 }

References CPU_FEATURE_AVAILABLE, and CPU_HAS_ALTIVEC.

◆ SDL_HasAVX()

SDL_bool SDL_HasAVX ( void  )

This function returns true if the CPU has AVX features.

Definition at line 735 of file SDL_cpuinfo.c.

736 {
738 }

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 741 of file SDL_cpuinfo.c.

742 {
744 }

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 747 of file SDL_cpuinfo.c.

748 {
750 }

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 693 of file SDL_cpuinfo.c.

694 {
696 }

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 753 of file SDL_cpuinfo.c.

754 {
756 }

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 681 of file SDL_cpuinfo.c.

682 {
684 }

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 705 of file SDL_cpuinfo.c.

706 {
708 }

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 711 of file SDL_cpuinfo.c.

712 {
714 }

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 717 of file SDL_cpuinfo.c.

718 {
720 }

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 723 of file SDL_cpuinfo.c.

724 {
726 }

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 729 of file SDL_cpuinfo.c.

730 {
732 }

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 823 of file SDL_cpuinfo.c.

824 {
825  const size_t alignment = SDL_SIMDGetAlignment();
826  const size_t padding = alignment - (len % alignment);
827  const size_t padded = (padding != alignment) ? (len + padding) : len;
828  Uint8 *retval = NULL;
829  Uint8 *ptr = (Uint8 *) SDL_malloc(padded + alignment + sizeof (void *));
830  if (ptr) {
831  /* store the actual malloc pointer right before our aligned pointer. */
832  retval = ptr + sizeof (void *);
833  retval += alignment - (((size_t) retval) % alignment);
834  *(((void **) retval) - 1) = ptr;
835  }
836  return retval;
837 }

References NULL, 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 840 of file SDL_cpuinfo.c.

841 {
842  if (ptr) {
843  void **realptr = (void **) ptr;
844  realptr--;
845  SDL_free(*(((void **) ptr) - 1));
846  }
847 }

References 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 813 of file SDL_cpuinfo.c.

814 {
815  if (SDL_SIMDAlignment == 0xFFFFFFFF) {
816  SDL_GetCPUFeatures(); /* make sure this has been calculated */
817  }
819  return SDL_SIMDAlignment;
820 }

References SDL_assert, SDL_GetCPUFeatures(), and SDL_SIMDAlignment.

Referenced by SDL_SIMDAlloc().

SDL_CACHELINE_SIZE
#define SDL_CACHELINE_SIZE
Definition: SDL_cpuinfo.h:114
SDL_GetCPUType
static const char * SDL_GetCPUType(void)
Definition: SDL_cpuinfo.c:486
SDL_GetCPUFeatures
static Uint32 SDL_GetCPUFeatures(void)
Definition: SDL_cpuinfo.c:618
CPU_HAS_SSE
#define CPU_HAS_SSE
Definition: SDL_cpuinfo.c:90
NULL
#define NULL
Definition: begin_code.h:167
b
GLboolean GLboolean GLboolean b
Definition: SDL_opengl_glext.h:1109
CPU_HAS_SSE41
#define CPU_HAS_SSE41
Definition: SDL_cpuinfo.c:93
CPU_HAS_AVX2
#define CPU_HAS_AVX2
Definition: SDL_cpuinfo.c:96
CPU_HAS_ALTIVEC
#define CPU_HAS_ALTIVEC
Definition: SDL_cpuinfo.c:87
SDL_SystemRAM
static int SDL_SystemRAM
Definition: SDL_cpuinfo.c:758
CPU_HAS_3DNOW
#define CPU_HAS_3DNOW
Definition: SDL_cpuinfo.c:89
CPU_FEATURE_AVAILABLE
#define CPU_FEATURE_AVAILABLE(f)
Definition: SDL_cpuinfo.c:679
a
GLboolean GLboolean GLboolean GLboolean a
Definition: SDL_opengl_glext.h:1109
c
const GLubyte * c
Definition: SDL_opengl_glext.h:11093
CPU_HAS_NEON
#define CPU_HAS_NEON
Definition: SDL_cpuinfo.c:97
CPU_HAS_SSE42
#define CPU_HAS_SSE42
Definition: SDL_cpuinfo.c:94
SDL_SIMDAlignment
static Uint32 SDL_SIMDAlignment
Definition: SDL_cpuinfo.c:615
len
GLenum GLsizei len
Definition: SDL_opengl_glext.h:2926
Uint8
uint8_t Uint8
Definition: SDL_stdinc.h:179
retval
SDL_bool retval
Definition: testgamecontroller.c:65
SDL_free
#define SDL_free
Definition: SDL_dynapi_overrides.h:377
CPU_HAS_SSE2
#define CPU_HAS_SSE2
Definition: SDL_cpuinfo.c:91
CPU_HAS_RDTSC
#define CPU_HAS_RDTSC
Definition: SDL_cpuinfo.c:86
CPU_HAS_AVX512F
#define CPU_HAS_AVX512F
Definition: SDL_cpuinfo.c:98
SDL_SIMDGetAlignment
size_t SDL_SIMDGetAlignment(void)
Report the alignment this system needs for SIMD allocations.
Definition: SDL_cpuinfo.c:813
CPU_HAS_MMX
#define CPU_HAS_MMX
Definition: SDL_cpuinfo.c:88
SDL_assert
#define SDL_assert(condition)
Definition: SDL_assert.h:169
size
GLsizeiptr size
Definition: SDL_opengl_glext.h:537
Uint64
uint64_t Uint64
Definition: SDL_stdinc.h:216
CPU_HAS_SSE3
#define CPU_HAS_SSE3
Definition: SDL_cpuinfo.c:92
Uint32
uint32_t Uint32
Definition: SDL_stdinc.h:203
cpuid
#define cpuid(func, a, b, c, d)
Definition: SDL_cpuinfo.c:250
CPU_HAS_AVX
#define CPU_HAS_AVX
Definition: SDL_cpuinfo.c:95
SDL_malloc
#define SDL_malloc
Definition: SDL_dynapi_overrides.h:374
SDL_strcmp
#define SDL_strcmp
Definition: SDL_dynapi_overrides.h:417
void
const SDL_PRINTF_FORMAT_STRING char int const SDL_PRINTF_FORMAT_STRING char int const SDL_PRINTF_FORMAT_STRING char int const SDL_PRINTF_FORMAT_STRING char const char const SDL_SCANF_FORMAT_STRING char return SDL_ThreadFunction const char void return Uint32 return Uint32 void
Definition: SDL_dynapi_procs.h:89
size_t
unsigned int size_t
Definition: SDL_config_windows.h:68
Sint64
int64_t Sint64
Definition: SDL_stdinc.h:210
d
const SDL_PRINTF_FORMAT_STRING char int const SDL_PRINTF_FORMAT_STRING char int const SDL_PRINTF_FORMAT_STRING char int const SDL_PRINTF_FORMAT_STRING char const char const SDL_SCANF_FORMAT_STRING char return SDL_ThreadFunction const char void return Uint32 return Uint32 SDL_AssertionHandler void SDL_SpinLock SDL_atomic_t int int return SDL_atomic_t return void void void return void return int return SDL_AudioSpec SDL_AudioSpec return int int return return int SDL_RWops int SDL_AudioSpec Uint8 ** d
Definition: SDL_dynapi_procs.h:117
SDL_CPUCount
static int SDL_CPUCount
Definition: SDL_cpuinfo.c:444