src/cpuinfo/SDL_cpuinfo.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 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_cpuinfo.h"

#if defined(__MACOSX__) && (defined(__ppc__) || defined(__ppc64__))
#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;
/* *INDENT-OFF* */
#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, 200000h        ; 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(__i386)
	__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
/* *INDENT-ON* */
    return has_CPUID;
}

static __inline__ int
CPU_getCPUIDFeatures(void)
{
    int features = 0;
/* *INDENT-OFF* */
#if defined(__GNUC__) && defined(i386)
	__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(__GNUC__) && defined(__x86_64__)
	__asm__ (
"        movq    %%rbx,%%rdi\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"
"        movq    %%rdi,%%rbx\n"
	: "=m" (features)
	:
	: "%rax", "%rcx", "%rdx", "%rdi"
	);
#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(__i386) || 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
/* *INDENT-ON* */
    return features;
}

static __inline__ int
CPU_getCPUIDFeaturesExt(void)
{
    int features = 0;
/* *INDENT-OFF* */
#if defined(__GNUC__) && defined(i386)
	__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(__GNUC__) && defined (__x86_64__)
	__asm__ (
"        movq    %%rbx,%%rdi\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"
"        movq    %%rdi,%%rbx\n"
	: "=m" (features)
	:
	: "%rax", "%rcx", "%rdx", "%rdi"
	);
#elif (defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)
	__asm {
        mov     eax,80000000h       ; Query for extended functions
        cpuid                       ; Get extended function limit
        cmp     eax,80000001h
        jl      done                ; Nope, we dont have function 800000001h
        mov     eax,80000001h       ; Setup extended function 800000001h
        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
/* *INDENT-ON* */
    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__) || defined(__ppc64__))
    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 */

/* vi: set ts=4 sw=4 expandtab: */