diff --git a/sync.go b/sync.go
index d559d34..470d0b0 100644
--- a/sync.go
+++ b/sync.go
@@ -2,6 +2,7 @@ package q5
 
 import (
 	"sync"
+	"sync/atomic"
 )
 
 type ConcurrentMap[T1 string | int | int32 | int64, T2 any] struct {
@@ -69,3 +70,10 @@ func (this *ConcurrentMap[T1, T2]) Swap(key T1, value T2) (*T2, bool) {
 		return nil, loaded
 	}
 }
+
+func AtomicStoreInt64WhenGreater(srcVal *int64, trgVal *int64) {
+	tmpVal := atomic.LoadInt64(srcVal)
+	if tmpVal > *trgVal {
+		atomic.StoreInt64(trgVal, tmpVal)
+	}
+}