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Improve ARM runtime feature detection on Linux #176

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Improve ARM runtime feature detection on Linux #176

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20 changes: 20 additions & 0 deletions features/features_cpu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -337,8 +337,27 @@ static void arm_enable_runfast_mode(void)
#endif

#if defined(__linux__) && !defined(CPU_X86)
#if __ARM_ARCH
#include <sys/auxv.h>
#endif

static unsigned char check_arm_cpu_feature(const char* feature)
{
#if __ARM_ARCH < 8
uint64_t hwcap = getauxval(AT_HWCAP);
if (!strcmp(feature, "neon"))
return (hwcap & HWCAP_ARM_NEON) != 0;
if (!strcmp(feature, "vfpv3"))
return (hwcap & HWCAP_ARM_VFPv3) != 0;
if (!strcmp(feature, "vfpv4"))
return (hwcap & HWCAP_ARM_VFPv4) != 0;
return 0;
#elif __ARM_ARCH == 8
uint64_t hwcap = getauxval(AT_HWCAP);
if (!strcmp(feature, "asimd"))
return (hwcap & HWCAP_ASIMD) != 0;
return 0;
#else
Comment on lines +340 to +360
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@SpriteOvO SpriteOvO Aug 29, 2022 •
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This PR broke builds for architectures other than x86 and ARM.

AT_HWCAP, HWCAP_ARM_NEON, HWCAP_ARM_VFPv3 and HWCAP_ARM_VFPv4 macros are not defined on other architectures.

Suggested change
#if __ARM_ARCH
#include <sys/auxv.h>
#endif
static unsigned char check_arm_cpu_feature(const char* feature)
{
#if __ARM_ARCH < 8
uint64_t hwcap = getauxval(AT_HWCAP);
if (!strcmp(feature, "neon"))
return (hwcap & HWCAP_ARM_NEON) != 0;
if (!strcmp(feature, "vfpv3"))
return (hwcap & HWCAP_ARM_VFPv3) != 0;
if (!strcmp(feature, "vfpv4"))
return (hwcap & HWCAP_ARM_VFPv4) != 0;
return 0;
#elif __ARM_ARCH == 8
uint64_t hwcap = getauxval(AT_HWCAP);
if (!strcmp(feature, "asimd"))
return (hwcap & HWCAP_ASIMD) != 0;
return 0;
#else
#if defined(__ARM_ARCH)
#include <sys/auxv.h>
#endif
static unsigned char check_arm_cpu_feature(const char* feature)
{
#if defined(__ARM_ARCH) && __ARM_ARCH < 8
uint64_t hwcap = getauxval(AT_HWCAP);
if (!strcmp(feature, "neon"))
return (hwcap & HWCAP_ARM_NEON) != 0;
if (!strcmp(feature, "vfpv3"))
return (hwcap & HWCAP_ARM_VFPv3) != 0;
if (!strcmp(feature, "vfpv4"))
return (hwcap & HWCAP_ARM_VFPv4) != 0;
return 0;
#elif defined(__ARM_ARCH) && __ARM_ARCH == 8
uint64_t hwcap = getauxval(AT_HWCAP);
if (!strcmp(feature, "asimd"))
return (hwcap & HWCAP_ASIMD) != 0;
return 0;
#else

char line[1024];
unsigned char status = 0;
RFILE *fp = filestream_open("/proc/cpuinfo",
Expand All @@ -362,6 +381,7 @@ static unsigned char check_arm_cpu_feature(const char* feature)
filestream_close(fp);

return status;
#endif
}

#if !defined(_SC_NPROCESSORS_ONLN)
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