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5d418de2b6
arm.h still have CPU feature detection for Microsoft Compiler that is used by WinCE. Since we don't have the target for WinCE, we should remove it. Also, even if you need it for Win32/arm that is Windows Mobile and Windows IOT in feature, this is unnecessary. Win32/arm ABI requires thumb2+NEON at least. MozReview-Commit-ID: 6dYjIRY0Suo --HG-- extra : rebase_source : 34db8ed7d3d60bafdfc735b036e891554a0e56c5
148 lines
4.1 KiB
C++
148 lines
4.1 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* compile-time and runtime tests for whether to use various ARM extensions */
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#include "arm.h"
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#if defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
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// arm.h has parallel #ifs which declare MOZILLA_ARM_HAVE_CPUID_DETECTION.
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// We don't check it here so that we get compile errors if it's defined, but
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// we don't compile one of these detection methods. The detection code here is
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// based on the CPU detection in libtheora.
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# if defined(__linux__) || defined(ANDROID)
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# include <stdio.h>
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# include <stdlib.h>
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# include <string.h>
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enum{
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MOZILLA_HAS_EDSP_FLAG=1,
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MOZILLA_HAS_ARMV6_FLAG=2,
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MOZILLA_HAS_ARMV7_FLAG=4,
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MOZILLA_HAS_NEON_FLAG=8
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};
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static unsigned
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get_arm_cpu_flags(void)
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{
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unsigned flags;
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FILE *fin;
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bool armv6_processor = false;
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flags = 0;
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/*Reading /proc/self/auxv would be easier, but that doesn't work reliably on
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Android. This also means that detection will fail in Scratchbox, which is
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desirable, as NEON does not work in the qemu shipped with the Maemo 5 SDK.
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I don't know if /proc/self/auxv would do any better in that case, anyway,
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or if it would return random flags from the host CPU.*/
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fin = fopen ("/proc/cpuinfo","r");
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if (fin != nullptr)
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{
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/*512 should be enough for anybody (it's even enough for all the flags that
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x86 has accumulated... so far).*/
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char buf[512];
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while (fgets(buf, 511, fin) != nullptr)
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{
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if (memcmp(buf, "Features", 8) == 0)
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{
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char *p;
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p = strstr(buf, " edsp");
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if (p != nullptr && (p[5] == ' ' || p[5] == '\n'))
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flags |= MOZILLA_HAS_EDSP_FLAG;
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p = strstr(buf, " neon");
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if( p != nullptr && (p[5] == ' ' || p[5] == '\n'))
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flags |= MOZILLA_HAS_NEON_FLAG;
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}
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if (memcmp(buf, "CPU architecture:", 17) == 0)
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{
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int version;
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version = atoi(buf + 17);
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if (version >= 6)
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flags |= MOZILLA_HAS_ARMV6_FLAG;
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if (version >= 7)
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flags |= MOZILLA_HAS_ARMV7_FLAG;
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}
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/* media/webrtc/trunk/src/system_wrappers/source/cpu_features_arm.c
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* Unfortunately, it seems that certain ARMv6-based CPUs
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* report an incorrect architecture number of 7!
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*
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* We try to correct this by looking at the 'elf_format'
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* field reported by the 'Processor' field, which is of the
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* form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
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* an ARMv6-one.
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*/
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if (memcmp(buf, "Processor\t:", 11) == 0) {
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if (strstr(buf, "(v6l)") != 0) {
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armv6_processor = true;
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}
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}
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}
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fclose(fin);
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}
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if (armv6_processor) {
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// ARMv6 pretending to be ARMv7? clear flag
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if (flags & MOZILLA_HAS_ARMV7_FLAG) {
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flags &= ~MOZILLA_HAS_ARMV7_FLAG;
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}
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}
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return flags;
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}
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// Cache a local copy so we only have to read /proc/cpuinfo once.
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static unsigned arm_cpu_flags = get_arm_cpu_flags();
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# if !defined(MOZILLA_PRESUME_EDSP)
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static bool
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check_edsp(void)
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{
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return (arm_cpu_flags & MOZILLA_HAS_EDSP_FLAG) != 0;
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}
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# endif
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# if !defined(MOZILLA_PRESUME_ARMV6)
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static bool
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check_armv6(void)
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{
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return (arm_cpu_flags & MOZILLA_HAS_ARMV6_FLAG) != 0;
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}
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# endif
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# if !defined(MOZILLA_PRESUME_ARMV7)
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static bool
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check_armv7(void)
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{
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return (arm_cpu_flags & MOZILLA_HAS_ARMV7_FLAG) != 0;
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}
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# endif
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# if !defined(MOZILLA_PRESUME_NEON)
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static bool
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check_neon(void)
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{
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return (arm_cpu_flags & MOZILLA_HAS_NEON_FLAG) != 0;
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}
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# endif
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# endif // defined(__linux__) || defined(ANDROID)
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namespace mozilla {
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namespace arm_private {
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# if !defined(MOZILLA_PRESUME_EDSP)
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bool edsp_enabled = check_edsp();
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# endif
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# if !defined(MOZILLA_PRESUME_ARMV6)
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bool armv6_enabled = check_armv6();
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# endif
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# if !defined(MOZILLA_PRESUME_ARMV7)
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bool armv7_enabled = check_armv7();
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# endif
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# if !defined(MOZILLA_PRESUME_NEON)
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bool neon_enabled = check_neon();
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# endif
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} // namespace arm_private
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} // namespace mozilla
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#endif // MOZILLA_ARM_HAVE_CPUID_DETECTION
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