diff --git a/lib/std/atomic.c3 b/lib/std/atomic.c3
index 45963ef2f..b75625a8f 100644
--- a/lib/std/atomic.c3
+++ b/lib/std/atomic.c3
@@ -130,6 +130,61 @@ macro @atomic_exec(#func, data, value, ordering) @local
 
 module std::atomic;
 
+macro @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, $success, failure) {
+	switch(failure)
+	{
+		case AtomicOrdering.RELAXED.ordinal: return $$compare_exchange(ptr, expected, desired, false, false, $success, AtomicOrdering.RELAXED.ordinal, 0);
+		case AtomicOrdering.ACQUIRE.ordinal: return $$compare_exchange(ptr, expected, desired, false, false, $success, AtomicOrdering.ACQUIRE.ordinal, 0);
+		case AtomicOrdering.SEQ_CONSISTENT.ordinal: return $$compare_exchange(ptr, expected, desired, false, false, $success, AtomicOrdering.SEQ_CONSISTENT.ordinal, 0);
+		default: assert(false, "Unrecognized failure ordering");
+	}
+	return 0;
+}
+
+macro @__atomic_compare_exchange_ordering_success(ptr, expected, desired, success, failure)
+{
+	switch(success)
+	{
+		case AtomicOrdering.RELAXED.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.RELAXED.ordinal, failure);
+		case AtomicOrdering.ACQUIRE.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.ACQUIRE.ordinal, failure);
+		case AtomicOrdering.RELEASE.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.RELEASE.ordinal, failure);
+		case AtomicOrdering.ACQUIRE_RELEASE.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.ACQUIRE_RELEASE.ordinal, failure);
+		case AtomicOrdering.SEQ_CONSISTENT.ordinal: return @__atomic_compare_exchange_ordering_failure(ptr, expected, desired, AtomicOrdering.SEQ_CONSISTENT.ordinal, failure);
+		default: assert(false, "Unrecognized success ordering");
+	}
+	return 0;
+}
+
+fn CInt __atomic_compare_exchange(CInt size, any* ptr, any* expected, any* desired, CInt success, CInt failure) @extern("__atomic_compare_exchange") @export
+{
+	switch (size)
+	{
+		case 1:
+			char* pt = (char*)ptr;
+			char ex = *(char*)expected;
+			char de = *(char*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure)) return 1;
+		case 2:
+			short* pt = (short*)ptr;
+			short ex = *(short*)expected;
+			short de = *(short*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure)) return 1;
+		case 4:
+			int* pt = (int*)ptr;
+			int ex = *(int*)expected;
+			int de = *(int*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure)) return 1;
+		case 8:
+			long* pt = (long*)ptr;
+			long ex = *(long*)expected;
+			long de = *(long*)desired;
+			if (ex == @__atomic_compare_exchange_ordering_success(pt, ex, de, success, failure)) return 1;
+		default:
+			assert(false, "Unsuported size (%d) for atomic_compare_exchange", size);
+	}
+	return 0;
+}
+
 /**
  * @param [&in] ptr "the variable or dereferenced pointer to the data."
  * @param [in] y "the value to be added to ptr."