57 lines
1.1 KiB
C++
57 lines
1.1 KiB
C++
/*
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* \brief FPU implementation specific to x86
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* \author Stefan Kalkowski
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* \date 2016-01-19
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*/
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/*
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* Copyright (C) 2016 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/* core includes */
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#include <cpu.h>
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void Genode::Fpu::init()
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{
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Cpu::Cr0::access_t cr0_value = Cpu::Cr0::read();
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Cpu::Cr4::access_t cr4_value = Cpu::Cr4::read();
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Cpu::Cr0::Mp::set(cr0_value);
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Cpu::Cr0::Em::clear(cr0_value);
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Cpu::Cr0::Ts::set(cr0_value);
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Cpu::Cr0::Ne::set(cr0_value);
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Cpu::Cr0::write(cr0_value);
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Cpu::Cr4::Osfxsr::set(cr4_value);
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Cpu::Cr4::Osxmmexcpt::set(cr4_value);
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Cpu::Cr4::write(cr4_value);
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}
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void Genode::Fpu::disable() {
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Cpu::Cr0::write(Cpu::Cr0::read() | Cpu::Cr0::Ts::bits(1)); }
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bool Genode::Fpu::enabled() { return !Cpu::Cr0::Ts::get(Cpu::Cr0::read()); }
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bool Genode::Fpu::fault(Context &context)
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{
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if (enabled()) return false;
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enable();
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if (_context == &context) return true;
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if (_context) {
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_save();
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_context->_fpu = nullptr;
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}
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_context = &context;
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_context->_fpu = this;
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_load();
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return true;
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}
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