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88 lines
3.4 KiB
C++
88 lines
3.4 KiB
C++
/*
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* This file is part of the KDE libraries
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* Copyright (C) 2003 Fredrik Hglund <fredrik@kde.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <csignal>
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#include <csetjmp>
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#include <config-workspace.h>
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#include "kcpuinfo.h"
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#if defined(__GNUC__)
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# define HAVE_GNU_INLINE_ASM
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#endif
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static int getCpuFeatures()
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{
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volatile int features = 0;
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#if defined( HAVE_GNU_INLINE_ASM ) && defined( __i386__ )
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bool haveCPUID = false;
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int result = 0;
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// First check if the CPU supports the CPUID instruction
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__asm__ __volatile__(
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// Try to toggle the CPUID bit in the EFLAGS register
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"pushf \n\t" // Push the EFLAGS register onto the stack
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"popl %%ecx \n\t" // Pop the value into ECX
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"movl %%ecx, %%edx \n\t" // Copy ECX to EDX
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"xorl $0x00200000, %%ecx \n\t" // Toggle bit 21 (CPUID) in ECX
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"pushl %%ecx \n\t" // Push the modified value onto the stack
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"popf \n\t" // Pop it back into EFLAGS
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// Check if the CPUID bit was successfully toggled
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"pushf \n\t" // Push EFLAGS back onto the stack
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"popl %%ecx \n\t" // Pop the value into ECX
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"xorl %%eax, %%eax \n\t" // Zero out the EAX register
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"cmpl %%ecx, %%edx \n\t" // Compare ECX with EDX
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"je .Lno_cpuid_support%= \n\t" // Jump if they're identical
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"movl $1, %%eax \n\t" // Set EAX to true
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".Lno_cpuid_support%=: \n\t"
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: "=a"(haveCPUID) : : "%ecx", "%edx" );
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// If we don't have CPUID we won't have the other extensions either
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if ( ! haveCPUID )
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return 0L;
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// Execute CPUID with the feature request bit set
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__asm__ __volatile__(
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"pushl %%ebx \n\t" // Save EBX
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"movl $1, %%eax \n\t" // Set EAX to 1 (features request)
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"cpuid \n\t" // Call CPUID
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"popl %%ebx \n\t" // Restore EBX
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: "=d"(result) : : "%eax", "%ecx" );
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// Test bit 23 (MMX support)
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if ( result & 0x00800000 )
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features |= KCPUInfo::IntelMMX;
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#endif //HAVE_GNU_INLINE_ASM
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return features;
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}
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unsigned int KCPUInfo::s_features = getCpuFeatures();
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