/**
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* \file
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* ARM hardware feature detection
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*
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* Authors:
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* Alex Rønne Petersen (alexrp@xamarin.com)
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* Elijah Taylor (elijahtaylor@google.com)
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* Miguel de Icaza (miguel@xamarin.com)
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* Neale Ferguson (Neale.Ferguson@SoftwareAG-usa.com)
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* Paolo Molaro (lupus@xamarin.com)
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* Rodrigo Kumpera (kumpera@gmail.com)
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* Sebastien Pouliot (sebastien@xamarin.com)
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* Zoltan Varga (vargaz@xamarin.com)
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*
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* Copyright 2003 Ximian, Inc.
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* Copyright 2003-2011 Novell, Inc
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* Copyright 2006 Broadcom
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* Copyright 2007-2008 Andreas Faerber
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* Copyright 2011-2013 Xamarin Inc
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* Licensed under the MIT license. See LICENSE file in the project root for full license information.
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*/
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#include "mono/utils/mono-hwcap.h"
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#if defined(HAVE_SYS_AUXV_H) && !defined(HOST_ANDROID)
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#include <sys/auxv.h>
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#elif defined(__APPLE__)
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#include <mach/machine.h>
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#include <sys/sysctl.h>
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#include <sys/types.h>
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#else
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#if defined (HAVE_SYS_UTSNAME_H)
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#include <sys/utsname.h>
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#endif
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#include <stdio.h>
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#endif
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void
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mono_hwcap_arch_init (void)
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{
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#if defined(HAVE_SYS_AUXV_H) && !defined(HOST_ANDROID)
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unsigned long hwcap;
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unsigned long platform;
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if ((hwcap = getauxval(AT_HWCAP))) {
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/* HWCAP_ARM_THUMB */
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if (hwcap & 0x00000004)
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mono_hwcap_arm_has_thumb = TRUE;
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/* HWCAP_ARM_VFP */
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if (hwcap & 0x00000040)
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mono_hwcap_arm_has_vfp = TRUE;
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/* HWCAP_ARM_VFPv3 */
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if (hwcap & 0x00002000)
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mono_hwcap_arm_has_vfp3 = TRUE;
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/* HWCAP_ARM_VFPv3D16 */
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if (hwcap & 0x00004000)
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mono_hwcap_arm_has_vfp3_d16 = TRUE;
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/* TODO: Find a way to detect Thumb 2. */
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}
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if ((platform = getauxval(AT_PLATFORM))) {
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const char *str = (const char *) platform;
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if (str [1] >= '5')
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mono_hwcap_arm_is_v5 = TRUE;
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if (str [1] >= '6')
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mono_hwcap_arm_is_v6 = TRUE;
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if (str [1] >= '7')
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mono_hwcap_arm_is_v7 = TRUE;
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/* TODO: Find a way to detect v7s. */
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}
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#elif defined(__APPLE__)
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cpu_subtype_t sub_type;
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size_t length = sizeof (sub_type);
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sysctlbyname ("hw.cpusubtype", &sub_type, &length, NULL, 0);
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if (sub_type == CPU_SUBTYPE_ARM_V5TEJ || sub_type == CPU_SUBTYPE_ARM_XSCALE) {
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mono_hwcap_arm_is_v5 = TRUE;
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} else if (sub_type == CPU_SUBTYPE_ARM_V6) {
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mono_hwcap_arm_is_v5 = TRUE;
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mono_hwcap_arm_is_v6 = TRUE;
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} else if (sub_type == CPU_SUBTYPE_ARM_V7 || sub_type == CPU_SUBTYPE_ARM_V7F || sub_type == CPU_SUBTYPE_ARM_V7K) {
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mono_hwcap_arm_is_v5 = TRUE;
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mono_hwcap_arm_is_v6 = TRUE;
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mono_hwcap_arm_is_v7 = TRUE;
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}
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/* TODO: Find a way to detect features like Thumb and VFP. */
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#elif defined (_WIN32)
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/* From MSDN:
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* Windows on ARM presumes that it is running on an ARMv7 architecture at all times.
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* Floating-point support in the form of VFPv3-D32 or later must be present in hardware.
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* The VFP must support both single-precision and double-precision floating-point in hardware.
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*
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* The Windows runtime does not support emulation of floating-point to enable running on non-VFP hardware.
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* Advanced SIMD Extensions (NEON) support—this includes both integer and floating-point operations—must also be present in hardware.
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* No run-time support for emulation is provided.
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*
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* Integer divide support (UDIV/SDIV) is strongly recommended but not required.
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* Platforms that lack integer divide support may incur a performance penalty because
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* these operations have to be trapped and possibly patched.
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*
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* The instruction set for Windows on ARM is strictly limited to Thumb-2.
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* All code executed on this platform is expected to start and remain in Thumb mode at all times.
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*/
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mono_hwcap_arm_is_v5 = TRUE;
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mono_hwcap_arm_is_v6 = TRUE;
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mono_hwcap_arm_is_v7 = TRUE;
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mono_hwcap_arm_has_vfp = TRUE;
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mono_hwcap_arm_has_vfp3 = TRUE;
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mono_hwcap_arm_has_vfp3_d16 = TRUE;
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mono_hwcap_arm_has_thumb = TRUE;
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mono_hwcap_arm_has_thumb2 = TRUE;
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#else
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/* We can't use the auxiliary vector on Android due to
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* permissions, so fall back to /proc/cpuinfo. We also
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* hit this path if the target doesn't have sys/auxv.h.
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*/
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#if defined (HAVE_SYS_UTSNAME_H)
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struct utsname name;
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/* Only fails if `name` is invalid (it isn't). */
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g_assert (!uname (&name));
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if (!strncmp (name.machine, "aarch64", 7) || !strncmp (name.machine, "armv8", 5)) {
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/*
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* We're a 32-bit program running on an ARMv8 system.
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* Whether the system is actually 32-bit or 64-bit
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* doesn't matter to us. The important thing is that
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* all 3 of ARMv8's execution states (A64, A32, T32)
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* are guaranteed to have all of the features that
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* we want to detect and use.
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*
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* We do this ARMv8 detection via uname () because
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* in the early days of ARMv8 on Linux, the
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* /proc/cpuinfo format was a disaster and there
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* were multiple (merged into mainline) attempts at
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* cleaning it up (read: breaking applications that
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* tried to rely on it). So now multiple ARMv8
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* systems in the wild have different /proc/cpuinfo
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* output, some of which are downright useless.
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*
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* So, when it comes to detecting ARMv8 in a 32-bit
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* program, it's better to just avoid /proc/cpuinfo
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* entirely. Maybe in a decade or two, we won't
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* have to worry about this mess that the Linux ARM
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* maintainers created. One can hope.
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*/
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mono_hwcap_arm_is_v5 = TRUE;
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mono_hwcap_arm_is_v6 = TRUE;
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mono_hwcap_arm_is_v7 = TRUE;
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mono_hwcap_arm_has_vfp = TRUE;
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mono_hwcap_arm_has_vfp3 = TRUE;
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mono_hwcap_arm_has_vfp3_d16 = TRUE;
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mono_hwcap_arm_has_thumb = TRUE;
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mono_hwcap_arm_has_thumb2 = TRUE;
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}
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#endif
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char buf [512];
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char *line;
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FILE *file = fopen ("/proc/cpuinfo", "r");
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if (file) {
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while ((line = fgets (buf, 512, file))) {
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if (!strncmp (line, "Processor", 9) ||
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!strncmp (line, "model name", 10)) {
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char *ver = strstr (line, "(v");
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if (ver) {
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if (ver [2] >= '5')
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mono_hwcap_arm_is_v5 = TRUE;
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if (ver [2] >= '6')
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mono_hwcap_arm_is_v6 = TRUE;
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if (ver [2] >= '7')
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mono_hwcap_arm_is_v7 = TRUE;
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/* TODO: Find a way to detect v7s. */
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}
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continue;
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}
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if (!strncmp (line, "Features", 8)) {
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if (strstr (line, "thumb"))
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mono_hwcap_arm_has_thumb = TRUE;
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/* TODO: Find a way to detect Thumb 2. */
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if (strstr (line, "vfp"))
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mono_hwcap_arm_has_vfp = TRUE;
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if (strstr (line, "vfpv3"))
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mono_hwcap_arm_has_vfp3 = TRUE;
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if (strstr (line, "vfpv3-d16"))
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mono_hwcap_arm_has_vfp3_d16 = TRUE;
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continue;
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}
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}
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fclose (file);
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}
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#endif
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}
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