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