From d9044ec5553c946e20154b7b5c61cd3979472f60 Mon Sep 17 00:00:00 2001
From: Ruiyu Ni <ruiyu.ni@intel.com>
Date: Tue, 20 Jan 2015 08:46:31 +0000
Subject: Use RLE (Run Length Encoding) to improve debugging performance.

DEBUG_AGENT_REVISION is DEBUG_AGENT_REVISION_03 to disable this feature and will be changed to DEBUG_AGENT_REVISION_04 when new version of HOST is released.
Reduce the stack usage by re-using the same buffer to send/receive packet.
Zero out the buffer before fxsave so that the reserved field in the buffer remains 0 for better RLE compression ratio.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16628 6f19259b-4bc3-4df7-8a09-765794883524
---
 .../DebugAgent/DebugAgentCommon/Ia32/AsmFuncs.asm   | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

(limited to 'SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32')

diff --git a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/AsmFuncs.asm b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/AsmFuncs.asm
index 2aaf5b7b4c..377ade7c3b 100644
--- a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/AsmFuncs.asm
+++ b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/AsmFuncs.asm
@@ -1,6 +1,6 @@
 ;------------------------------------------------------------------------------
 ;
-; Copyright (c) 2010 - 2013, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.<BR>
 ; 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
@@ -302,17 +302,22 @@ NoExtrPush:
     mov     eax, dr0
     push    eax
 
+    ;; Clear Direction Flag
+    cld
+
     ;; FX_SAVE_STATE_IA32 FxSaveState;
-    sub esp, 512
-    mov edi, esp
+    sub     esp, 512
+    mov     edi, esp
+    ;; Clear the buffer
+    xor     eax, eax
+    mov     ecx, 128 ;= 512 / 4
+    rep     stosd
+    mov     edi, esp
     db 0fh, 0aeh, 00000111y ;fxsave [edi]
 
-    ;; save the exception data    
+    ;; save the exception data
     push    dword ptr [ebp + 8]
 
-    ;; Clear Direction Flag
-    cld
-    	
     ; call the C interrupt process function
     push    esp     ; Structure
     push    ebx     ; vector
@@ -323,7 +328,7 @@ NoExtrPush:
     add     esp, 4
 
     ;; FX_SAVE_STATE_IA32 FxSaveState;
-    mov esi, esp
+    mov     esi, esp
     db 0fh, 0aeh, 00001110y ; fxrstor [esi]
     add esp, 512
 
-- 
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