template specializations for limited std::atomic<u128> support

6fc6a8e4 · Nickolai Zeldovich · 871863c7 · 6fc6a8e4
--- a/kernel/cpprt.cc
+++ b/kernel/cpprt.cc
@@ -23,3 +23,30 @@ __cxa_pure_virtual(void)
 {
  panic("__cxa_pure_virtual");
 }
+namespace std {
+template<>
+u128
+atomic<u128>::load(memory_order __m) const
+{
+  __sync_synchronize();
+  u128 v = _M_i;
+  __sync_synchronize();
+  return v;
+}
+template<>
+bool
+atomic<u128>::compare_exchange_weak(u128 &__i1, u128 i2, memory_order __m)
+{
+  // XXX no __sync_val_compare_and_swap for u128
+  u128 o = __i1;
+  bool ok = __sync_bool_compare_and_swap(&_M_i, o, i2);
+  if (!ok)
+    __i1 = _M_i;
+  return ok;
+}
+};