Diff: CThunk.h

Revision:

0:7de85300ea3a

Child:

1:53a00c956d82

diff -r 000000000000 -r 7de85300ea3a CThunk.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CThunk.h	Wed Aug 13 07:43:23 2014 +0000
@@ -0,0 +1,148 @@
+/* General C++ Object Thunking class
+ *
+ * - allows direct callbacks to non-static C++ class functions
+ * - keeps track for the corresponding class instance
+ * - supports an optional context parameter for the called function
+ * - ideally suited for class object receiving interrupts (NVIC_SetVector)
+ *
+ * Copyright (c) 2014 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+ 
+#ifndef __CTHUNK_H__
+#define __CTHUNK_H__
+
+/* IRQ/Exception compatible thunk entry function */
+typedef void (*CThunkEntry)(void);
+
+/* template for thunk trampoline */
+#ifdef __thumb__
+#define CTHUNK_OPCODES_SIZE 8
+#else
+#error "TODO: add support for non-thumb trampoline, too"
+#endif
+
+extern const uint8_t g_cthunk_opcodes[CTHUNK_OPCODES_SIZE];
+
+template<class T>
+class CThunk
+{
+    public:
+        typedef void (T::*CCallbackSimple)(void);
+        typedef void (T::*CCallback)(void* context);
+
+        inline CThunk(void)
+        {
+            /* copy ARM thumb compatible pcode preamble */
+            memcpy(
+                &m_thunk.code,
+                &g_cthunk_opcodes,
+                CTHUNK_OPCODES_SIZE
+            );
+            /* set remainder to zero */
+            memset(
+                &m_thunk.code + CTHUNK_OPCODES_SIZE,
+                0, sizeof(m_thunk.code) - CTHUNK_OPCODES_SIZE
+            );
+        }
+
+        inline CThunk(T &instance)
+        {
+            init(instance, NULL, NULL);
+        }
+
+        inline CThunk(T &instance, CCallback callback)
+        {
+            init(instance, callback, NULL);
+        }
+
+        inline CThunk(T &instance, CCallbackSimple callback)
+        {
+            init(instance, (CCallback)callback, NULL);
+        }
+
+        inline CThunk(T &instance, CCallback callback, void* context)
+        {
+            init(instance, callback, context);
+        }
+
+        inline CThunk& operator=(T &instance)
+        {
+            m_thunk.instance = &instance;
+            return *this;
+        }
+
+        inline CThunk& operator=(CCallback callback)
+        {
+            m_thunk.callback = callback;
+            return *this;
+        }
+
+        inline CThunk& operator=(CCallbackSimple callback)
+        {
+            m_thunk.callback = (CCallback)callback;
+            return *this;
+        }
+
+        inline CThunk& operator=(void* context)
+        {
+            m_thunk.context = context;
+            return *this;
+        }
+
+        inline CThunk& operator=(uint32_t context)
+        {
+            m_thunk.context = (void*)context;
+            return *this;
+        }
+
+        /* get thunk entry point for connecting rhunk to an IRQ table */
+        inline operator CThunkEntry(void)
+        {
+            return (CThunkEntry)&m_thunk.code;
+        }
+
+        /* get thunk entry point for connecting rhunk to an IRQ table */
+        inline operator uint32_t(void)
+        {
+            return (uint32_t)&m_thunk.code;
+        }
+
+        /* simple test function */
+        inline void call(void)
+        {
+            ((CThunkEntry)&m_thunk.code)();
+        }
+
+    private:
+        typedef struct
+        {
+            uint8_t code[CTHUNK_OPCODES_SIZE];
+            T* instance;
+            void* context;
+            CCallback callback;
+        } __attribute__((packed)) CThunkTrampoline;
+
+        CThunkTrampoline m_thunk;
+
+        inline void init(T &instance, CCallback callback, void* context)
+        {
+            memcpy(&m_thunk.code, &g_cthunk_opcodes, CTHUNK_OPCODES_SIZE);
+            m_thunk.instance = &instance;
+            m_thunk.context = context;
+            m_thunk.callback = callback;
+        }
+};
+
+#endif/*__CTHUNK_H__*/
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