BaseUefiCpuLib: Preserve EBX register in InitializeFloatingPointUnits

The EBX register should be preserved for the IA32 C calling convention.
The use of the CPUID instruction was modifying the EBX register, so
we push and pop EBX.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9573 6f19259b-4bc3-4df7-8a09-765794883524

diff --git a/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.S b/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.S
index c4a2f6fb83bd2b18bcb72bfc32359a4d838a0270..4c74957f04afaf6ef79288ab047bb30e02ab16a9 100644 (file)
--- a/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.S
+++ b/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.S
@@ -1,19 +1,19 @@
-#------------------------------------------------------------------------------
-#*
-#*   Copyright 2009, Intel Corporation
-#*   All rights reserved. This program and the accompanying materials
-#*   are licensed and made available under the terms and conditions of the BSD License
-#*   which accompanies this distribution.  The full text of the license may be found at
-#*   http://opensource.org/licenses/bsd-license.php
-#*
-#*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
-#*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-#*
-#*
-#------------------------------------------------------------------------------
-
-
-
+#------------------------------------------------------------------------------\r
+#*\r
+#*   Copyright 2009, Intel Corporation\r
+#*   All rights reserved. This program and the accompanying materials\r
+#*   are licensed and made available under the terms and conditions of the BSD License\r
+#*   which accompanies this distribution.  The full text of the license may be found at\r
+#*   http://opensource.org/licenses/bsd-license.php\r
+#*\r
+#*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+#*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+#*\r
+#*\r
+#------------------------------------------------------------------------------\r
+\r
+\r
+\r
 #\r
 # Float control word initial value: \r
 # all exceptions masked, double-precision, round-to-nearest\r
@@ -23,18 +23,21 @@ ASM_PFX(mFpuControlWord): .word     0x027F
 # Multimedia-extensions control word:\r
 # all exceptions masked, round-to-nearest, flush to zero for masked underflow\r
 #\r
-ASM_PFX(mMmxControlWord): .long     0x01F80
-
-#
+ASM_PFX(mMmxControlWord): .long     0x01F80\r
+\r
+#\r
 # Initializes floating point units for requirement of UEFI specification.\r
 #\r
 # This function initializes floating-point control word to 0x027F (all exceptions\r
 # masked,double-precision, round-to-nearest) and multimedia-extensions control word\r
 # (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero\r
-# for masked underflow).
-#
-ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits)
-ASM_PFX(InitializeFloatingPointUnits):
+# for masked underflow).\r
+#\r
+ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits)\r
+ASM_PFX(InitializeFloatingPointUnits):\r
+\r
+    pushl   %ebx\r
+\r
     #\r
     # Initialize floating point units\r
     #\r
@@ -49,22 +52,24 @@ ASM_PFX(InitializeFloatingPointUnits):
     cpuid\r
     btl     $25, %edx\r
     jnc     Done\r
-    
-    #
-    # Set OSFXSR bit 9 in CR4
-    #
-    movl    %cr4, %eax 
-    or      $200, %eax
-    movl    %eax, %cr4
-    
+    \r
+    #\r
+    # Set OSFXSR bit 9 in CR4\r
+    #\r
+    movl    %cr4, %eax \r
+    or      $200, %eax\r
+    movl    %eax, %cr4\r
+    \r
     #\r
     # The processor should support SSE instruction and we can use\r
     # ldmxcsr instruction\r
     #\r
-    ldmxcsr ASM_PFX(mMmxControlWord)
-
-Done:
-    ret
-
-#END
-
+    ldmxcsr ASM_PFX(mMmxControlWord)\r
+\r
+Done:\r
+    popl    %ebx\r
+\r
+    ret\r
+\r
+#END\r
+\r

diff --git a/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.asm b/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.asm
index 55244c72a9ee8e4e5912cd77f8196a365e506cc8..083473311e59688019907811024f760b683b6655 100644 (file)
--- a/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.asm
+++ b/UefiCpuPkg/Library/BaseUefiCpuLib/Ia32/InitializeFpu.asm
@@ -30,15 +30,18 @@ mMmxControlWord       DD      01F80h
     .xmm\r
     .code\r
 \r
-;
+;\r
 ; Initializes floating point units for requirement of UEFI specification.\r
 ;\r
 ; This function initializes floating-point control word to 0x027F (all exceptions\r
 ; masked,double-precision, round-to-nearest) and multimedia-extensions control word\r
 ; (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero\r
-; for masked underflow).
+; for masked underflow).\r
 ;\r
 InitializeFloatingPointUnits PROC PUBLIC\r
+\r
+    push    ebx\r
+\r
     ;\r
     ; Initialize floating point units\r
     ;\r
@@ -67,6 +70,7 @@ InitializeFloatingPointUnits PROC PUBLIC
     ;\r
     ldmxcsr mMmxControlWord\r
 Done:\r
+    pop     ebx\r
 \r
     ret\r
 \r