1 files changed, 76 insertions, 0 deletions
diff --git a/src/jit/fp.h b/src/jit/fp.h
new file mode 100644
index 0000000000..de7a8933b2
--- /dev/null
+++ b/src/jit/fp.h
@@ -0,0 +1,76 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information. 
+//
+
+
+#ifndef _JIT_FP
+
+#define _JIT_FP
+
+// Auxiliary structures.
+#if FEATURE_STACK_FP_X87
+
+enum dummyFPenum
+{
+    #define REGDEF(name, rnum, mask, sname)  dummmy_##name = rnum,
+    #include "registerfp.h"
+
+    FP_VIRTUALREGISTERS,
+};
+
+
+// FlatFPStateX87 holds the state of the virtual register file. For each
+// virtual register we keep track to which physical register we're 
+// mapping. We also keep track of the physical stack.
+
+#define FP_PHYSICREGISTERS FP_VIRTUALREGISTERS
+#define FP_VRNOTMAPPED     -1
+
+struct FlatFPStateX87
+{
+public:  
+    void                    Init                    (FlatFPStateX87* pFrom = 0);
+    bool                    Mapped                  (unsigned uEntry); // Is virtual register mapped
+    void                    Unmap                   (unsigned uEntry); // Unmaps a virtual register
+    void                    Associate               (unsigned uEntry, unsigned uStack);
+    unsigned                StackToST               (unsigned uEntry); // Maps the stack to a ST(x) entry
+    unsigned                VirtualToST             (unsigned uEntry);
+    unsigned                STToVirtual             (unsigned uST);
+    unsigned                TopIndex                ();
+    unsigned                TopVirtual              ();
+    void                    Rename                  (unsigned uVirtualTo, unsigned uVirtualFrom);
+    unsigned                Pop                     ();
+    void                    Push                    (unsigned uEntry);
+    bool                    IsEmpty                 ();
+            
+    // Debug/test methods
+    static bool             AreEqual                (FlatFPStateX87* pSrc, FlatFPStateX87* pDst);
+    #ifdef DEBUG    
+    bool                    IsValidEntry            (unsigned uEntry);
+    bool                    IsConsistent            ();
+    void                    UpdateMappingFromStack  ();
+    void                    Dump                    ();
+
+    // In some optimizations the stack will be inconsistent in some transactions. We want to keep
+    // the checks for everthing else, so if have the stack in an inconsistent state, you must
+    // ignore it on purpose.
+    bool                    m_bIgnoreConsistencyChecks;
+
+    inline void IgnoreConsistencyChecks(bool bIgnore) 
+    {
+        m_bIgnoreConsistencyChecks = bIgnore;
+    }
+    #else
+    inline void IgnoreConsistencyChecks(bool bIgnore) 
+    {       
+    }    
+    #endif
+
+    unsigned                m_uVirtualMap[FP_VIRTUALREGISTERS];
+    unsigned                m_uStack[FP_PHYSICREGISTERS];
+    unsigned                m_uStackSize;
+};    
+    
+#endif // FEATURE_STACK_FP_X87
+#endif