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authorPatrick Rudolph <siro@das-labor.org>2017-01-15 10:49:48 +0100
committerMartin Roth <martinroth@google.com>2017-03-08 04:44:12 +0100
commitb854ae26494ca7cdb7a6804c7319f669e6c713dd (patch)
tree52195640248a1b13c4df692837ba22094e60501d /payloads/libpayload/arch
parentf13bd41c505925af260a27ab9f24a43308d7992c (diff)
libpayload-x86: Enable SSE and FPU when present
Allows to use SSE and floating point in payloads without digging to much into x86 assembly code. Tested on Lenovo T500 (Intel Core2Duo). Both floating point operation and SSE is properly working. Change-Id: I4a5fc633f158de421b70435a8bfdc0dcaa504c72 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/18345 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Diffstat (limited to 'payloads/libpayload/arch')
-rw-r--r--payloads/libpayload/arch/x86/head.S43
1 files changed, 43 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/x86/head.S b/payloads/libpayload/arch/x86/head.S
index 94a4d41167..52504706db 100644
--- a/payloads/libpayload/arch/x86/head.S
+++ b/payloads/libpayload/arch/x86/head.S
@@ -2,6 +2,7 @@
* This file is part of the libpayload project.
*
* Copyright (C) 2008 Advanced Micro Devices, Inc.
+ * Copyright (C) 2017 Patrick Rudolph <siro@das-labor.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -89,6 +90,48 @@ _init:
movl $_stack, %esp
pushl %eax
+ /* Enable special x86 functions if present. */
+ pushl %eax
+ pushl %ebx
+ pushl %ecx
+ pushl %edx
+
+ movl $0, %eax
+ cpuid
+ /* Test if CPUID(eax=1) is available. */
+ test %eax, %eax
+ je cpuid_done
+
+ /* Get CPU features. */
+ movl $1, %eax
+ cpuid
+
+cpuid_fpu:
+ /* Test if x87 FPU is present */
+ test $1, %edx
+ je cpuid_sse
+
+ fninit
+ movl %cr0, %eax
+ andl $0xFFFFFFFB, %eax /* clear EM */
+ orl $0x00000022, %eax /* set MP, NE */
+ movl %eax, %cr0
+
+cpuid_sse:
+ /* Test if SSE is available */
+ test $0x02000000, %edx
+ je cpuid_done
+
+ movl %cr4, %eax
+ orl $0x00000600, %eax /* set OSFXSR, OSXMMEXCPT */
+ movl %eax, %cr4
+
+cpuid_done:
+ popl %edx
+ popl %ecx
+ popl %ebx
+ popl %eax
+
/* Let's rock. */
call start_main