diff options
Diffstat (limited to 'src/cpu')
| -rw-r--r-- | src/cpu/x86/fpu_enable.inc | 39 | ||||
| -rw-r--r-- | src/cpu/x86/mmx_disable.inc | 24 | ||||
| -rw-r--r-- | src/cpu/x86/sse_disable.inc | 34 | ||||
| -rw-r--r-- | src/cpu/x86/sse_enable.inc | 30 |
4 files changed, 110 insertions, 17 deletions
diff --git a/src/cpu/x86/fpu_enable.inc b/src/cpu/x86/fpu_enable.inc index bd7a7ff630..f3eedcdaf6 100644 --- a/src/cpu/x86/fpu_enable.inc +++ b/src/cpu/x86/fpu_enable.inc @@ -1,10 +1,39 @@ - /* preserve BIST in %eax */ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2002 Eric Biederman <ebiederm@xmission.com> + * + * 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: - movl %eax, %ebp + /* Preserve BIST. */ + movl %eax, %ebp - /* Disable floating point emulation */ + /* + * 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 + andl $~(1 << 2), %eax movl %eax, %cr0 - movl %ebp, %eax + /* Restore BIST. */ + movl %ebp, %eax diff --git a/src/cpu/x86/mmx_disable.inc b/src/cpu/x86/mmx_disable.inc index 97d62d60f5..1a4e70f0c6 100644 --- a/src/cpu/x86/mmx_disable.inc +++ b/src/cpu/x86/mmx_disable.inc @@ -1,2 +1,24 @@ - /* Clear out an mmx state */ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2002 Eric Biederman <ebiederm@xmission.com> + * + * 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 + */ + + /* + * Execute the EMMS (Empty MMX Technology State) instruction. + */ emms + diff --git a/src/cpu/x86/sse_disable.inc b/src/cpu/x86/sse_disable.inc index a42cb41259..37458c9cd2 100644 --- a/src/cpu/x86/sse_disable.inc +++ b/src/cpu/x86/sse_disable.inc @@ -1,8 +1,26 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2002 Eric Biederman <ebiederm@xmission.com> + * + * 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 + */ + /* * Put the processor back into a reset state - * with respect to the xmm registers. + * with respect to the XMM registers. */ - xorps %xmm0, %xmm0 xorps %xmm1, %xmm1 xorps %xmm2, %xmm2 @@ -12,7 +30,15 @@ xorps %xmm6, %xmm6 xorps %xmm7, %xmm7 - /* Disable sse instructions */ + /* + * Disable SSE instructions. + * + * Clear CR4[9] (OSFXSR) and CR4[10] (OSXMMEXCPT) so that the + * processor can no longer execute SSE instructions, and unmasked + * SIMD floating point exceptions will generate an invalid opcode + * exception (#UD). + */ movl %cr4, %eax - andl $~(3<<9), %eax + andl $~(3 << 9), %eax movl %eax, %cr4 + diff --git a/src/cpu/x86/sse_enable.inc b/src/cpu/x86/sse_enable.inc index 95724b71f7..8dc4f3a2ae 100644 --- a/src/cpu/x86/sse_enable.inc +++ b/src/cpu/x86/sse_enable.inc @@ -1,14 +1,30 @@ - /* preserve BIST in %eax */ - movl %eax, %ebp +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2002 Eric Biederman <ebiederm@xmission.com> + * + * 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 + */ - /* - * Enable the use of the xmm registers - */ + /* Preserve BIST. */ + movl %eax, %ebp - /* Enable sse instructions */ + /* Enable SSE instructions. */ movl %cr4, %eax - orl $(1<<9), %eax + orl $(1 << 9), %eax movl %eax, %cr4 + /* Restore BIST. */ movl %ebp, %eax |