40 lines
1.3 KiB
PHP
40 lines
1.3 KiB
PHP
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2002 Eric Biederman <ebiederm@xmission.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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__fpu_start:
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/* Preserve BIST. */
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movl %eax, %ebp
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/*
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* Clear the CR0[2] bit (the "Emulation" flag, EM).
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*
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* This indicates that the processor has an (internal or external)
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* x87 FPU, i.e. floating point operations will be executed by the
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* hardware (and not emulated in software).
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*
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* Additionally, if this bit is not cleared, MMX/SSE instructions won't
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* work, i.e., they will trigger an invalid opcode exception (#UD).
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*/
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movl %cr0, %eax
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andl $~(1 << 2), %eax
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movl %eax, %cr0
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/* Restore BIST. */
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movl %ebp, %eax
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