From 16b20de9541fa482c901b531bd6a49782e0dd12a Mon Sep 17 00:00:00 2001
From: "Sergey Semyonov (Serge)" <ion2@mail.ru>
Date: Mon, 21 Apr 2008 19:19:15 +0000
Subject: [PATCH] optimizing switching of the FPU context

git-svn-id: svn://kolibrios.org@794 a494cfbc-eb01-0410-851d-a64ba20cac60
---
 kernel/trunk/core/sched.inc | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/kernel/trunk/core/sched.inc b/kernel/trunk/core/sched.inc
index 1f61f57405..5020343505 100644
--- a/kernel/trunk/core/sched.inc
+++ b/kernel/trunk/core/sched.inc
@@ -232,11 +232,17 @@ do_change_task:
 ;        mov [tss._esp0], eax
         mov ax, graph_data
         mov gs, ax
-        mov ecx, cr0
-        or ecx, CR0_TS   ;set task switch flag
-        mov cr0, ecx
-        inc   [context_counter] ;noname & halyavin
 
+        mov eax, [CURRENT_TASK]
+        cmp eax, [fpu_owner]
+        clts                             ;clear a task switch flag
+        je @F
+                                         ;and set it again if the owner
+        mov ecx, cr0                     ;of a fpu has changed
+        or ecx, CR0_TS
+        mov cr0, ecx
+@@:
+        inc   [context_counter] ;noname & halyavin
         test [ebx+APPDATA.dbg_state], 1
         jnz @F
         ret