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ARM: Create configure option --enable-arm-simd to govern assembly opt…

…imizations
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bavison committed Oct 25, 2019
1 parent 59beacc commit 6a6a05289ef9bdbef646b2b8e6d998444212bcfa
Showing with 99 additions and 1 deletion.
  1. +37 −0 configure.ac
  2. +1 −0 include/SDL_config.h.in
  3. +5 −0 include/SDL_cpuinfo.h
  4. +56 −1 src/cpuinfo/SDL_cpuinfo.c
@@ -1303,6 +1303,42 @@ AS_HELP_STRING([--enable-libsamplerate-shared], [dynamically load libsamplerate
fi
}

dnl Check for ARM instruction support using gas syntax
CheckARM()
{
AC_ARG_ENABLE(arm-simd,
AC_HELP_STRING([--enable-arm-simd], [use SIMD assembly blitters on ARM [[default=yes]]]),
enable_arm_simd=$enableval, enable_arm_simd=yes)
if test x$enable_video = xyes -a x$enable_assembly = xyes -a x$enable_arm_simd = xyes; then
save_CFLAGS="$CFLAGS"
have_arm_simd=no
CFLAGS="-x assembler-with-cpp $CFLAGS"

AC_MSG_CHECKING(for ARM SIMD)
AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
.text
.arch armv6
.object_arch armv4
.arm
.altmacro
#ifndef __ARM_EABI__
#error EABI is required (to be sure that calling conventions are compatible)
#endif
pld [r0]
uqadd8 r0, r0, r0
]])], have_arm_simd=yes)
AC_MSG_RESULT($have_arm_simd)

CFLAGS="$save_CFLAGS"

if test x$have_arm_simd = xyes; then
AC_DEFINE(SDL_ARM_SIMD_BLITTERS)
dnl SOURCES="$SOURCES $srcdir/src/video/arm/pixman-arm-simd*.c"
SOURCES="$SOURCES $srcdir/src/video/arm/pixman-arm-simd*.S"
fi
fi
}

dnl See if GCC's -fvisibility=hidden is supported (gcc4 and later, usually).
dnl Details of this flag are here: http://gcc.gnu.org/wiki/Visibility
CheckVisibilityHidden()
@@ -3396,6 +3432,7 @@ case "$host" in
CheckDiskAudio
CheckDummyAudio
CheckDLOPEN
CheckARM
CheckOSS
CheckALSA
CheckPulseAudio
@@ -407,6 +407,7 @@
/* Enable assembly routines */
#undef SDL_ASSEMBLY_ROUTINES
#undef SDL_ALTIVEC_BLITTERS
#undef SDL_ARM_SIMD_BLITTERS

/* Enable ime support */
#undef SDL_USE_IME
@@ -186,6 +186,11 @@ extern DECLSPEC SDL_bool SDLCALL SDL_HasAVX2(void);
*/
extern DECLSPEC SDL_bool SDLCALL SDL_HasAVX512F(void);

/**
* This function returns true if the CPU has ARM SIMD (ARMv6) features.
*/
extern DECLSPEC SDL_bool SDLCALL SDL_HasARMSIMD(void);

/**
* This function returns true if the CPU has NEON (ARM SIMD) features.
*/
@@ -96,6 +96,7 @@
#define CPU_HAS_AVX2 (1 << 10)
#define CPU_HAS_NEON (1 << 11)
#define CPU_HAS_AVX512F (1 << 12)
#define CPU_HAS_ARM_SIMD (1 << 13)

#if SDL_ALTIVEC_BLITTERS && HAVE_SETJMP && !__MACOSX__ && !__OpenBSD__
/* This is the brute force way of detecting instruction sets...
@@ -325,7 +326,50 @@ CPU_haveAltiVec(void)
return altivec;
}

#if defined(__LINUX__) && defined(__ARM_ARCH) && !defined(HAVE_GETAUXVAL)
#ifdef __linux__

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <elf.h>

static SDL_bool
CPU_haveARMSIMD(void)
{
int arm_simd = 0;
int fd;

fd = open("/proc/self/auxv", O_RDONLY);
if (fd >= 0)
{
Elf32_auxv_t aux;
while (read(fd, &aux, sizeof aux) == sizeof aux)
{
if (aux.a_type == AT_PLATFORM)
{
const char *plat = (const char *) aux.a_un.a_val;
arm_simd = strncmp(plat, "v6l", 3) == 0 ||
strncmp(plat, "v7l", 3) == 0;
}
}
close(fd);
}
return arm_simd;
}

#else

static SDL_bool
CPU_haveARMSIMD(void)
{
#warning SDL_HasARMSIMD is not implemented for this ARM platform. Write me.
return 0;
}

#endif

#if (defined(__LINUX__) || defined(__ANDROID__)) && defined(__ARM_ARCH) && !defined(HAVE_GETAUXVAL)
static int
readProcAuxvForNeon(void)
{
@@ -668,6 +712,10 @@ SDL_GetCPUFeatures(void)
SDL_CPUFeatures |= CPU_HAS_AVX512F;
SDL_SIMDAlignment = SDL_max(SDL_SIMDAlignment, 64);
}
if (CPU_haveARMSIMD()) {
SDL_CPUFeatures |= CPU_HAS_ARM_SIMD;
SDL_SIMDAlignment = SDL_max(SDL_SIMDAlignment, 16);
}
if (CPU_haveNEON()) {
SDL_CPUFeatures |= CPU_HAS_NEON;
SDL_SIMDAlignment = SDL_max(SDL_SIMDAlignment, 16);
@@ -749,6 +797,12 @@ SDL_HasAVX512F(void)
return CPU_FEATURE_AVAILABLE(CPU_HAS_AVX512F);
}

SDL_bool
SDL_HasARMSIMD(void)
{
return CPU_FEATURE_AVAILABLE(CPU_HAS_ARM_SIMD);
}

SDL_bool
SDL_HasNEON(void)
{
@@ -870,6 +924,7 @@ main()
printf("AVX: %d\n", SDL_HasAVX());
printf("AVX2: %d\n", SDL_HasAVX2());
printf("AVX-512F: %d\n", SDL_HasAVX512F());
printf("ARM SIMD: %d\n", SDL_HasARMSIMD());
printf("NEON: %d\n", SDL_HasNEON());
printf("RAM: %d MB\n", SDL_GetSystemRAM());
return 0;

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