From dfd1c031d679b6425d6f7827989f66895f68412e Mon Sep 17 00:00:00 2001
From: Aleksandar Andrejevic <aandrejevic@reactos.org>
Date: Sat, 26 Oct 2013 17:33:10 +0000
Subject: [PATCH] [FAST486] Implement the CLTS instruction.

svn path=/branches/ntvdm/; revision=60752
---
 lib/fast486/extraops.c | 19 ++++++++++++++++++-
 lib/fast486/extraops.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/fast486/extraops.c b/lib/fast486/extraops.c
index 8ac7fc2d6fb..7c6da5e9c06 100644
--- a/lib/fast486/extraops.c
+++ b/lib/fast486/extraops.c
@@ -45,7 +45,7 @@ Fast486ExtendedHandlers[FAST486_NUM_OPCODE_HANDLERS] =
     NULL, // TODO: OPCODE 0x03 NOT IMPLEMENTED
     NULL, // TODO: OPCODE 0x04 NOT IMPLEMENTED
     NULL, // TODO: OPCODE 0x05 NOT IMPLEMENTED
-    NULL, // TODO: OPCODE 0x06 NOT IMPLEMENTED
+    Fast486ExtOpcodeClts,
     NULL, // TODO: OPCODE 0x07 NOT IMPLEMENTED
     NULL, // TODO: OPCODE 0x08 NOT IMPLEMENTED
     NULL, // TODO: OPCODE 0x09 NOT IMPLEMENTED
@@ -299,6 +299,23 @@ Fast486ExtendedHandlers[FAST486_NUM_OPCODE_HANDLERS] =
 
 /* PUBLIC FUNCTIONS ***********************************************************/
 
+FAST486_OPCODE_HANDLER(Fast486ExtOpcodeClts)
+{
+    NO_LOCK_PREFIX();
+
+    /* The current privilege level must be zero */
+    if (Fast486GetCurrentPrivLevel(State) != 0)
+    {
+        Fast486Exception(State, FAST486_EXCEPTION_GP);
+        return FALSE;
+    }
+
+    /* Clear the task switch bit */
+    State->ControlRegisters[FAST486_REG_CR0] &= ~FAST486_CR0_TS;
+
+    return TRUE;
+}
+
 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeStoreControlReg)
 {
     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
diff --git a/lib/fast486/extraops.h b/lib/fast486/extraops.h
index d650c7499d2..46ad8610098 100644
--- a/lib/fast486/extraops.h
+++ b/lib/fast486/extraops.h
@@ -23,6 +23,7 @@
 #define _EXTRAOPS_H_
 
 /* DEFINES ********************************************************************/
+FAST486_OPCODE_HANDLER(Fast486ExtOpcodeClts);
 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeStoreControlReg);
 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeStoreDebugReg);
 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeLoadControlReg);