From 33ab387a79a67585bae356196e1ed9b58e123b3f Mon Sep 17 00:00:00 2001
From: Alexey Guseynov <kibergus@gmail.com>
Date: Sun, 12 Aug 2012 23:07:41 +0400
Subject: [PATCH] Correct implementation of gcc specific internal functions

---
 hardware/arduino/cores/arduino/abi.cpp | 61 ++++++++++++++++++++++++++
 hardware/arduino/cores/arduino/abi.h   | 19 ++++++++
 hardware/arduino/cores/arduino/new.cpp |  7 ---
 hardware/arduino/cores/arduino/new.h   |  8 ----
 4 files changed, 80 insertions(+), 15 deletions(-)
 create mode 100644 hardware/arduino/cores/arduino/abi.cpp
 create mode 100644 hardware/arduino/cores/arduino/abi.h

diff --git a/hardware/arduino/cores/arduino/abi.cpp b/hardware/arduino/cores/arduino/abi.cpp
new file mode 100644
index 00000000000..f9f8b1fc454
--- /dev/null
+++ b/hardware/arduino/cores/arduino/abi.cpp
@@ -0,0 +1,61 @@
+#include <abi.h>
+#include <stdint.h>
+// TODO Uncomment this once you have libstdc++
+//#include <exception>
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+namespace {
+// guard is an integer type big enough to hold flag and a mutex. 
+// By default gcc uses long long int and avr ABI does not change it
+// So we have 32 or 64 bits available. Actually, we need 16.
+
+inline char& flag_part(__guard *g) {
+    return *(reinterpret_cast<char*>(g));
+}
+
+inline uint8_t& sreg_part(__guard *g) {
+    return *(reinterpret_cast<uint8_t*>(g) + sizeof(char));
+}
+}
+
+int __cxa_guard_acquire(__guard *g) {
+    uint8_t oldSREG = SREG;
+    cli();
+    // Initialization of static variable has to be done with blocked interrupts
+    // because if this function is called from interrupt and sees that somebody
+    // else is already doing initialization it MUST wait until initializations
+    // is complete. That's impossible.
+    // If you don't want this overhead compile with -fno-threadsafe-statics
+    if (flag_part(g)) {
+        SREG = oldSREG;
+        return false;
+    } else {
+        sreg_part(g) = oldSREG;
+        return true;
+    }
+}
+
+void __cxa_guard_release (__guard *g) {
+    flag_part(g) = 1;
+    SREG = sreg_part(g);
+}
+
+void __cxa_guard_abort (__guard *g) {
+    SREG = sreg_part(g);
+}
+
+void __cxa_pure_virtual(void) {
+    // We might want to write some diagnostics to uart in this case
+    // TODO Uncomment this once you have libstdc++
+    //std::terminate();
+    abort();
+}
+
+void __cxa_deleted_virtual(void) {
+    // We might want to write some diagnostics to uart in this case
+    // TODO Uncomment this once you have libstdc++
+    //std::terminate();
+    abort();
+}
diff --git a/hardware/arduino/cores/arduino/abi.h b/hardware/arduino/cores/arduino/abi.h
new file mode 100644
index 00000000000..370087e8c20
--- /dev/null
+++ b/hardware/arduino/cores/arduino/abi.h
@@ -0,0 +1,19 @@
+/* Header to define cxx abi parts missing from avrlibc */
+
+#ifndef ABI_H_INCLUDED
+#define ABI_H_INCLUDED
+
+#include <stdlib.h>
+
+__extension__ typedef int __guard __attribute__((mode (__DI__)));
+
+extern "C" {
+int __cxa_guard_acquire(__guard *);
+void __cxa_guard_release (__guard *);
+void __cxa_guard_abort (__guard *); 
+
+void __cxa_pure_virtual(void) __attribute__ ((__noreturn__));
+void __cxa_deleted_virtual(void) __attribute__ ((__noreturn__));
+}
+
+#endif
diff --git a/hardware/arduino/cores/arduino/new.cpp b/hardware/arduino/cores/arduino/new.cpp
index 0f6d4220ef7..35d66a58c11 100644
--- a/hardware/arduino/cores/arduino/new.cpp
+++ b/hardware/arduino/cores/arduino/new.cpp
@@ -9,10 +9,3 @@ void operator delete(void * ptr)
 {
   free(ptr);
 } 
-
-int __cxa_guard_acquire(__guard *g) {return !*(char *)(g);};
-void __cxa_guard_release (__guard *g) {*(char *)g = 1;};
-void __cxa_guard_abort (__guard *) {}; 
-
-void __cxa_pure_virtual(void) {};
-
diff --git a/hardware/arduino/cores/arduino/new.h b/hardware/arduino/cores/arduino/new.h
index cd940ce8b26..bd2a1b0ce38 100644
--- a/hardware/arduino/cores/arduino/new.h
+++ b/hardware/arduino/cores/arduino/new.h
@@ -10,13 +10,5 @@
 void * operator new(size_t size);
 void operator delete(void * ptr); 
 
-__extension__ typedef int __guard __attribute__((mode (__DI__)));
-
-extern "C" int __cxa_guard_acquire(__guard *);
-extern "C" void __cxa_guard_release (__guard *);
-extern "C" void __cxa_guard_abort (__guard *); 
-
-extern "C" void __cxa_pure_virtual(void);
-
 #endif