[aandrejevic] 67528: [FAST486] Properly check the limit for "expand down" segments.

Author: aandrejevic
Date: Sun May  3 03:37:06 2015
New Revision: 67528

URL: http://svn.reactos.org/svn/reactos?rev=67528&view=rev
Log:
[FAST486]
Properly check the limit for "expand down" segments.

Modified:
    trunk/reactos/lib/fast486/common.c

Modified: trunk/reactos/lib/fast486/common.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/lib/fast486/common.c?rev=67...
==============================================================================
--- trunk/reactos/lib/fast486/common.c	[iso-8859-1] (original)
+++ trunk/reactos/lib/fast486/common.c	[iso-8859-1] Sun May  3 03:37:06 2015
@@ -47,11 +47,23 @@
     /* Get the cached descriptor */
     CachedDescriptor = &State->SegmentRegs[SegmentReg];

-    if ((Offset + Size - 1) > CachedDescriptor->Limit)
-    {
-        /* Read beyond limit */
-        Fast486Exception(State, FAST486_EXCEPTION_GP);
-        return FALSE;
+    if (InstFetch || !CachedDescriptor->DirConf)
+    {
+        if ((Offset + Size - 1) > CachedDescriptor->Limit)
+        {
+            /* Read beyond limit */
+            Fast486Exception(State, FAST486_EXCEPTION_GP);
+            return FALSE;
+        }
+    }
+    else
+    {
+        if (Offset < CachedDescriptor->Limit)
+        {
+            /* Read beyond limit */
+            Fast486Exception(State, FAST486_EXCEPTION_GP);
+            return FALSE;
+        }
     }

/* Check for protected mode */
@@ -157,11 +169,23 @@
     /* Get the cached descriptor */
     CachedDescriptor = &State->SegmentRegs[SegmentReg];

-    if ((Offset + Size - 1) > CachedDescriptor->Limit)
-    {
-        /* Write beyond limit */
-        Fast486Exception(State, FAST486_EXCEPTION_GP);
-        return FALSE;
+    if (!CachedDescriptor->DirConf)
+    {
+        if ((Offset + Size - 1) > CachedDescriptor->Limit)
+        {
+            /* Write beyond limit */
+            Fast486Exception(State, FAST486_EXCEPTION_GP);
+            return FALSE;
+        }
+    }
+    else
+    {
+        if (Offset < CachedDescriptor->Limit)
+        {
+            /* Read beyond limit */
+            Fast486Exception(State, FAST486_EXCEPTION_GP);
+            return FALSE;
+        }
     }

/* Check for protected mode */