[sginsberg] 68894: - Fix what should hopefully be the last bug in the floating point state save/load code -- in KiNpxHandler check if the state is loaded before unloading it instead of checking if ...

Author: sginsberg
Date: Tue Sep  1 13:20:50 2015
New Revision: 68894

URL: http://svn.reactos.org/svn/reactos?rev=68894&view=rev
Log:
- Fix what should hopefully be the last bug in the floating point state save/load code -- in KiNpxHandler check if the state is loaded before unloading it instead of checking if it is *unloaded* before... unloading it. Also clear up some comments.
- Thomas is da man.

Modified:
    trunk/reactos/ntoskrnl/ke/i386/traphdlr.c

Modified: trunk/reactos/ntoskrnl/ke/i386/traphdlr.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/traphdlr.c...
==============================================================================
--- trunk/reactos/ntoskrnl/ke/i386/traphdlr.c	[iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/ke/i386/traphdlr.c	[iso-8859-1] Tue Sep  1 13:20:50 2015
@@ -262,8 +262,8 @@
         }
     }

-    /* User or kernel trap -- get ready to issue an exception */
-    if (Thread->NpxState == NPX_STATE_NOT_LOADED)
+    /* User or kernel trap -- check if we need to unload the current state */
+    if (Thread->NpxState == NPX_STATE_LOADED)
     {
         /* Update CR0 */
         Cr0 = __readcr0();
@@ -310,8 +310,6 @@
     }

/* Get legal exceptions that software should handle */
-    /* We do this by first masking off from the Mask the bits we need, */
-    /* This is done so we can keep the FSW_STACK_FAULT bit in Error. */
     Mask &= (FSW_INVALID_OPERATION |
              FSW_DENORMAL |
              FSW_ZERO_DIVIDE |
@@ -323,9 +321,10 @@
     /* Check for invalid operation */
     if (Error & FSW_INVALID_OPERATION)
     {
-        /* NOTE: Stack fault is handled differently than any other case. */
-        /* 1. It's only raised for invalid operation. */
-        /* 2. It's only raised if invalid operation is not masked. */
+        /*
+         * Now check if this is actually a Stack Fault. This is needed because
+         * on x86 the Invalid Operation error is set for Stack Check faults as well.
+         */
         if (Error & FSW_STACK_FAULT)
         {
             /* Issue stack check fault */
@@ -335,12 +334,14 @@
                                      DataOffset,
                                      TrapFrame);
         }
-
-        /* Issue fault */
-        KiDispatchException1Args(STATUS_FLOAT_INVALID_OPERATION,
-                                 ErrorOffset,
-                                 0,
-                                 TrapFrame);
+        else
+        {
+            /* This is an invalid operation fault after all, so raise that instead */
+            KiDispatchException1Args(STATUS_FLOAT_INVALID_OPERATION,
+                                     ErrorOffset,
+                                     0,
+                                     TrapFrame);
+        }
     }

/* Check for divide by zero */