src/cpuinfo/SDL_cpuinfo.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* CPU feature detection for SDL */

#include "SDL.h"
#include "SDL_cpuinfo.h"

#if defined(__MACOSX__) && defined(__ppc__)
#include <sys/sysctl.h>         /* For AltiVec check */
#elif SDL_ALTIVEC_BLITTERS && HAVE_SETJMP
#include <signal.h>
#include <setjmp.h>
#endif

#define CPU_HAS_RDTSC	0x00000001
#define CPU_HAS_MMX	0x00000002
#define CPU_HAS_MMXEXT	0x00000004
#define CPU_HAS_3DNOW	0x00000010
#define CPU_HAS_3DNOWEXT 0x00000020
#define CPU_HAS_SSE	0x00000040
#define CPU_HAS_SSE2	0x00000080
#define CPU_HAS_ALTIVEC	0x00000100

#if SDL_ALTIVEC_BLITTERS && HAVE_SETJMP && !__MACOSX__
/* This is the brute force way of detecting instruction sets...
   the idea is borrowed from the libmpeg2 library - thanks!
 */
static jmp_buf jmpbuf;
static void
illegal_instruction (int sig)
{
    longjmp (jmpbuf, 1);
}
#endif /* HAVE_SETJMP */

static __inline__ int
CPU_haveCPUID (void)
{
    int has_CPUID = 0;
#if defined(__GNUC__) && defined(i386)
  __asm__ ("        pushfl                      # Get original EFLAGS             \n" "        popl    %%eax                                                 \n" "        movl    %%eax,%%ecx                                           \n" "        xorl    $0x200000,%%eax     # Flip ID bit in EFLAGS           \n" "        pushl   %%eax               # Save new EFLAGS value on stack  \n" "        popfl                       # Replace current EFLAGS value    \n" "        pushfl                      # Get new EFLAGS                  \n" "        popl    %%eax               # Store new EFLAGS in EAX         \n" "        xorl    %%ecx,%%eax         # Can not toggle ID bit,          \n" "        jz      1f                  # Processor=80486                 \n" "        movl    $1,%0               # We have CPUID support           \n" "1:                                                                    \n": "=m" (has_CPUID):
  :"%eax", "%ecx");
#elif defined(__GNUC__) && defined(__x86_64__)
/* Technically, if this is being compiled under __x86_64__ then it has 
CPUid by definition.  But it's nice to be able to prove it.  :)      */
  __asm__ ("        pushfq                      # Get original EFLAGS             \n" "        popq    %%rax                                                 \n" "        movq    %%rax,%%rcx                                           \n" "        xorl    $0x200000,%%eax     # Flip ID bit in EFLAGS           \n" "        pushq   %%rax               # Save new EFLAGS value on stack  \n" "        popfq                       # Replace current EFLAGS value    \n" "        pushfq                      # Get new EFLAGS                  \n" "        popq    %%rax               # Store new EFLAGS in EAX         \n" "        xorl    %%ecx,%%eax         # Can not toggle ID bit,          \n" "        jz      1f                  # Processor=80486                 \n" "        movl    $1,%0               # We have CPUID support           \n" "1:                                                                    \n": "=m" (has_CPUID):
  :"%rax", "%rcx");
#elif (defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)
    __asm {
        pushfd;
        Get original EFLAGS pop eax mov ecx, eax xor eax, 200000 h;
        Flip ID bit in EFLAGS push eax;
        Save new EFLAGS value on stack popfd;
        Replace current EFLAGS value pushfd;
        Get new EFLAGS pop eax;
        Store new EFLAGS in EAX xor eax, ecx;
        Can not toggle ID bit, jz done;
        Processor = 80486 mov has_CPUID, 1;
    We have CPUID support done:}
#elif defined(__sun) && defined(__x86)
    __asm ("       pushfl                 \n"
           "	popl    %eax           \n"
           "	movl    %eax,%ecx      \n"
           "	xorl    $0x200000,%eax \n"
           "	pushl   %eax           \n"
           "	popfl                  \n"
           "	pushfl                 \n"
           "	popl    %eax           \n"
           "	xorl    %ecx,%eax      \n"
           "	jz      1f             \n"
           "	movl    $1,-8(%ebp)    \n"
           "1:                            \n");
#elif defined(__sun) && defined(__amd64)
    __asm ("       pushfq                 \n"
           "       popq    %rax           \n"
           "       movq    %rax,%rcx      \n"
           "       xorl    $0x200000,%eax \n"
           "       pushq   %rax           \n"
           "       popfq                  \n"
           "       pushfq                 \n"
           "       popq    %rax           \n"
           "       xorl    %ecx,%eax      \n"
           "       jz      1f             \n"
           "       movl    $1,-8(%rbp)    \n"
           "1:                            \n");
#endif
    return has_CPUID;
}

static __inline__ int
CPU_getCPUIDFeatures (void)
{
    int features = 0;
#if defined(__GNUC__) && ( defined(i386) || defined(__x86_64__) )
  __asm__ ("        movl    %%ebx,%%edi\n" "        xorl    %%eax,%%eax         # Set up for CPUID instruction    \n" "        cpuid                       # Get and save vendor ID          \n" "        cmpl    $1,%%eax            # Make sure 1 is valid input for CPUID\n" "        jl      1f                  # We dont have the CPUID instruction\n" "        xorl    %%eax,%%eax                                           \n" "        incl    %%eax                                                 \n" "        cpuid                       # Get family/model/stepping/features\n" "        movl    %%edx,%0                                              \n" "1:                                                                    \n" "        movl    %%edi,%%ebx\n": "=m" (features):
  :"%eax", "%ecx", "%edx", "%edi");
#elif (defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)
    __asm {
        xor eax, eax;
    Set up for CPUID instruction
            cpuid; Get and save vendor ID
            cmp eax, 1; Make sure 1 is valid input for CPUID
            jl done; We dont have the CPUID instruction
            xor eax, eax
            inc eax
            cpuid; Get family / model / stepping / features
            mov features, edx done:}
#elif defined(__sun) && (defined(__x86) || defined(__amd64))
    __asm
        ("        movl    %ebx,%edi\n"
         "        xorl    %eax,%eax         \n"
         "        cpuid                     \n"
         "        cmpl    $1,%eax           \n"
         "        jl      1f                \n"
         "        xorl    %eax,%eax         \n"
         "        incl    %eax              \n"
         "        cpuid                     \n"
#ifdef __i386
         "        movl    %edx,-8(%ebp)     \n"
#else
         "        movl    %edx,-8(%rbp)     \n"
#endif
         "1:                                \n"
         "        movl    %edi,%ebx\n");
#endif
    return features;
}

static __inline__ int
CPU_getCPUIDFeaturesExt (void)
{
    int features = 0;
#if defined(__GNUC__) && (defined(i386) || defined (__x86_64__) )
  __asm__ ("        movl    %%ebx,%%edi\n" "        movl    $0x80000000,%%eax   # Query for extended functions    \n" "        cpuid                       # Get extended function limit     \n" "        cmpl    $0x80000001,%%eax                                     \n" "        jl      1f                  # Nope, we dont have function 800000001h\n" "        movl    $0x80000001,%%eax   # Setup extended function 800000001h\n" "        cpuid                       # and get the information         \n" "        movl    %%edx,%0                                              \n" "1:                                                                    \n" "        movl    %%edi,%%ebx\n": "=m" (features):
  :"%eax", "%ecx", "%edx", "%edi");
#elif (defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)
    __asm {
        mov eax, 80000000 h;
        Query for extended functions
            cpuid; Get extended function limit
            cmp eax, 80000001 h jl done; Nope
            , we dont have function 800000001 h mov eax, 80000001 h;
        Setup extended function 800000001 h cpuid;
    and get the information mov features, edx done:}
#elif defined(__sun) && ( defined(__i386) || defined(__amd64) )
    __asm ("        movl    %ebx,%edi\n"
           "        movl    $0x80000000,%eax \n"
           "        cpuid                    \n"
           "        cmpl    $0x80000001,%eax \n"
           "        jl      1f               \n"
           "        movl    $0x80000001,%eax \n"
           "        cpuid                    \n"
#ifdef __i386
           "        movl    %edx,-8(%ebp)   \n"
#else
           "        movl    %edx,-8(%rbp)   \n"
#endif
           "1:                               \n"
           "        movl    %edi,%ebx\n");
#endif
    return features;
}

static __inline__ int
CPU_haveRDTSC (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeatures () & 0x00000010);
    }
    return 0;
}

static __inline__ int
CPU_haveMMX (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeatures () & 0x00800000);
    }
    return 0;
}

static __inline__ int
CPU_haveMMXExt (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeaturesExt () & 0x00400000);
    }
    return 0;
}

static __inline__ int
CPU_have3DNow (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeaturesExt () & 0x80000000);
    }
    return 0;
}

static __inline__ int
CPU_have3DNowExt (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeaturesExt () & 0x40000000);
    }
    return 0;
}

static __inline__ int
CPU_haveSSE (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeatures () & 0x02000000);
    }
    return 0;
}

static __inline__ int
CPU_haveSSE2 (void)
{
    if (CPU_haveCPUID ()) {
        return (CPU_getCPUIDFeatures () & 0x04000000);
    }
    return 0;
}

static __inline__ int
CPU_haveAltiVec (void)
{
    volatile int altivec = 0;
#if defined(__MACOSX__) && defined(__ppc__)
    int selectors[2] = { CTL_HW, HW_VECTORUNIT };
    int hasVectorUnit = 0;
    size_t length = sizeof (hasVectorUnit);
    int error = sysctl (selectors, 2, &hasVectorUnit, &length, NULL, 0);
    if (0 == error)
        altivec = (hasVectorUnit != 0);
#elif SDL_ALTIVEC_BLITTERS && HAVE_SETJMP
    void (*handler) (int sig);
    handler = signal (SIGILL, illegal_instruction);
    if (setjmp (jmpbuf) == 0) {
        asm volatile ("mtspr 256, %0\n\t" "vand %%v0, %%v0, %%v0"::"r" (-1));
        altivec = 1;
    }
    signal (SIGILL, handler);
#endif
    return altivec;
}

static Uint32 SDL_CPUFeatures = 0xFFFFFFFF;

static Uint32
SDL_GetCPUFeatures (void)
{
    if (SDL_CPUFeatures == 0xFFFFFFFF) {
        SDL_CPUFeatures = 0;
        if (CPU_haveRDTSC ()) {
            SDL_CPUFeatures |= CPU_HAS_RDTSC;
        }
        if (CPU_haveMMX ()) {
            SDL_CPUFeatures |= CPU_HAS_MMX;
        }
        if (CPU_haveMMXExt ()) {
            SDL_CPUFeatures |= CPU_HAS_MMXEXT;
        }
        if (CPU_have3DNow ()) {
            SDL_CPUFeatures |= CPU_HAS_3DNOW;
        }
        if (CPU_have3DNowExt ()) {
            SDL_CPUFeatures |= CPU_HAS_3DNOWEXT;
        }
        if (CPU_haveSSE ()) {
            SDL_CPUFeatures |= CPU_HAS_SSE;
        }
        if (CPU_haveSSE2 ()) {
            SDL_CPUFeatures |= CPU_HAS_SSE2;
        }
        if (CPU_haveAltiVec ()) {
            SDL_CPUFeatures |= CPU_HAS_ALTIVEC;
        }
    }
    return SDL_CPUFeatures;
}

SDL_bool
SDL_HasRDTSC (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_RDTSC) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_HasMMX (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_MMX) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_HasMMXExt (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_MMXEXT) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_Has3DNow (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_3DNOW) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_Has3DNowExt (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_3DNOWEXT) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_HasSSE (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_SSE) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_HasSSE2 (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_SSE2) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

SDL_bool
SDL_HasAltiVec (void)
{
    if (SDL_GetCPUFeatures () & CPU_HAS_ALTIVEC) {
        return SDL_TRUE;
    }
    return SDL_FALSE;
}

#ifdef TEST_MAIN

#include <stdio.h>

int
main ()
{
    printf ("RDTSC: %d\n", SDL_HasRDTSC ());
    printf ("MMX: %d\n", SDL_HasMMX ());
    printf ("MMXExt: %d\n", SDL_HasMMXExt ());
    printf ("3DNow: %d\n", SDL_Has3DNow ());
    printf ("3DNowExt: %d\n", SDL_Has3DNowExt ());
    printf ("SSE: %d\n", SDL_HasSSE ());
    printf ("SSE2: %d\n", SDL_HasSSE2 ());
    printf ("AltiVec: %d\n", SDL_HasAltiVec ());
    return 0;
}

#endif /* TEST_MAIN */
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