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view src/cpuinfo/SDL_cpuinfo.c @ 4216:5b99971a27b4 SDL-1.2

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Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 09:27:08 +0000
parents 0a9a29fc00c2
children fa62bede8038
line wrap: on
line source

/*
    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.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, 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
	return has_CPUID;
}

static __inline__ int CPU_getCPUIDFeatures(void)
{
	int features = 0;
#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
	return features;
}

static __inline__ int CPU_getCPUIDFeaturesExt(void)
{
	int features = 0;
#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
	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 */