Initial commit: TXW82x FPV v2.7.0.7-42229 SDK + project sources

csky/csi_kernel/rhino/common/k_ffs.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2018 Alibaba Group Holding Limited
+ */
+
+/*
+DESCRIPTION
+This file provides method to find the least/most significant bit in 32 bit
+fields.
+*/
+
+#include "k_api.h"
+#include "k_ffs.h"
+#include "k_bitmap.h"
+
+/* find most significant bit set */
+
+int ffs32_msb(uint32_t bitmap)
+{
+    if (bitmap == 0)
+        {
+        return 0;
+        }
+
+    return 32 - krhino_find_first_bit(&bitmap);
+}
+
+
+/* find least significant bit set */
+
+int ffs32_lsb(uint32_t bitmap)
+{
+    uint32_t x;
+    int      lsbit;
+
+    if (bitmap == 0) 
+        {
+        return 0;
+        }
+
+    x = bitmap & -bitmap;
+    lsbit = krhino_find_first_bit((uint32_t *)(&x));
+
+    return 32 - lsbit;
+}
+