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efe5f0901c
Differential Revision: https://phabricator.services.mozilla.com/D42592 --HG-- extra : moz-landing-system : lando
65 lines
1.7 KiB
C++
65 lines
1.7 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 Power ISA-specific
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* extensions */
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#include "ppc.h"
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#include "mozilla/Unused.h"
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#include <stdio.h>
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#include <stdlib.h>
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#if defined(XP_LINUX)
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// Use the getauxval() function if available.
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// ARCH_3_00 wasn't defined until glibc 2.23, so include just in case.
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# include <sys/auxv.h>
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# ifndef PPC_FEATURE2_ARCH_3_00
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# define PPC_FEATURE2_ARCH_3_00 0x00800000
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# endif
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#endif
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const unsigned PPC_FLAG_VMX = 1;
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const unsigned PPC_FLAG_VSX = 2;
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const unsigned PPC_FLAG_VSX3 = 4;
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static signed get_ppc_cpu_flags(void) {
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// This could be expensive, so cache the result.
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static signed cpu_flags = -1;
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if (cpu_flags > -1) { // already checked
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return cpu_flags;
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}
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cpu_flags = 0;
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#if defined(XP_LINUX)
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// Try getauxval().
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unsigned long int cap = getauxval(AT_HWCAP);
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unsigned long int cap2 = getauxval(AT_HWCAP2);
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if (cap & PPC_FEATURE_HAS_ALTIVEC) {
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cpu_flags |= PPC_FLAG_VMX;
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}
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if (cap & PPC_FEATURE_HAS_VSX) {
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cpu_flags |= PPC_FLAG_VSX;
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}
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if (cap2 & PPC_FEATURE2_ARCH_3_00) {
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cpu_flags |= PPC_FLAG_VSX3;
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}
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#else
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// Non-Linux detection here. Currently, on systems other than Linux,
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// no CPU SIMD features will be detected.
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#endif
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return cpu_flags;
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}
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namespace mozilla {
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namespace ppc_private {
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bool vmx_enabled = !!(get_ppc_cpu_flags() & PPC_FLAG_VMX);
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bool vsx_enabled = !!(get_ppc_cpu_flags() & PPC_FLAG_VSX);
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bool vsx3_enabled = !!(get_ppc_cpu_flags() & PPC_FLAG_VSX3);
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} // namespace ppc_private
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} // namespace mozilla
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