1 files changed, 53 insertions, 0 deletions
diff --git a/src/common_audio/signal_processing_library/main/source/spl_sqrt_floor.c b/src/common_audio/signal_processing_library/main/source/spl_sqrt_floor.c
new file mode 100644
index 0000000000..aa36459ec4
--- /dev/null
+++ b/src/common_audio/signal_processing_library/main/source/spl_sqrt_floor.c
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/*
+ * This file contains the function WebRtcSpl_SqrtFloor().
+ * The description header can be found in signal_processing_library.h
+ *
+ */
+
+#include "signal_processing_library.h"
+
+#define WEBRTC_SPL_SQRT_ITER(N)                 \
+  try1 = root + (1 << (N));                     \
+  if (value >= try1 << (N))                     \
+  {                                             \
+    value -= try1 << (N);                       \
+    root |= 2 << (N);                           \
+  }
+
+// (out) Square root of input parameter
+WebRtc_Word32 WebRtcSpl_SqrtFloor(WebRtc_Word32 value)
+{
+    // new routine for performance, 4 cycles/bit in ARM
+    // output precision is 16 bits
+
+    WebRtc_Word32 root = 0, try1;
+
+    WEBRTC_SPL_SQRT_ITER (15);
+    WEBRTC_SPL_SQRT_ITER (14);
+    WEBRTC_SPL_SQRT_ITER (13);
+    WEBRTC_SPL_SQRT_ITER (12);
+    WEBRTC_SPL_SQRT_ITER (11);
+    WEBRTC_SPL_SQRT_ITER (10);
+    WEBRTC_SPL_SQRT_ITER ( 9);
+    WEBRTC_SPL_SQRT_ITER ( 8);
+    WEBRTC_SPL_SQRT_ITER ( 7);
+    WEBRTC_SPL_SQRT_ITER ( 6);
+    WEBRTC_SPL_SQRT_ITER ( 5);
+    WEBRTC_SPL_SQRT_ITER ( 4);
+    WEBRTC_SPL_SQRT_ITER ( 3);
+    WEBRTC_SPL_SQRT_ITER ( 2);
+    WEBRTC_SPL_SQRT_ITER ( 1);
+    WEBRTC_SPL_SQRT_ITER ( 0);
+
+    return root >> 1;
+}