summaryrefslogtreecommitdiffstats
path: root/media/libopus/silk/sum_sqr_shift.c
diff options
context:
space:
mode:
Diffstat (limited to 'media/libopus/silk/sum_sqr_shift.c')
-rw-r--r--media/libopus/silk/sum_sqr_shift.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/media/libopus/silk/sum_sqr_shift.c b/media/libopus/silk/sum_sqr_shift.c
new file mode 100644
index 000000000..129df191d
--- /dev/null
+++ b/media/libopus/silk/sum_sqr_shift.c
@@ -0,0 +1,86 @@
+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+- Neither the name of Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+***********************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "SigProc_FIX.h"
+
+/* Compute number of bits to right shift the sum of squares of a vector */
+/* of int16s to make it fit in an int32 */
+void silk_sum_sqr_shift(
+ opus_int32 *energy, /* O Energy of x, after shifting to the right */
+ opus_int *shift, /* O Number of bits right shift applied to energy */
+ const opus_int16 *x, /* I Input vector */
+ opus_int len /* I Length of input vector */
+)
+{
+ opus_int i, shft;
+ opus_int32 nrg_tmp, nrg;
+
+ nrg = 0;
+ shft = 0;
+ len--;
+ for( i = 0; i < len; i += 2 ) {
+ nrg = silk_SMLABB_ovflw( nrg, x[ i ], x[ i ] );
+ nrg = silk_SMLABB_ovflw( nrg, x[ i + 1 ], x[ i + 1 ] );
+ if( nrg < 0 ) {
+ /* Scale down */
+ nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 );
+ shft = 2;
+ i+=2;
+ break;
+ }
+ }
+ for( ; i < len; i += 2 ) {
+ nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
+ nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
+ nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, (opus_uint32)nrg_tmp, shft );
+ if( nrg < 0 ) {
+ /* Scale down */
+ nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 );
+ shft += 2;
+ }
+ }
+ if( i == len ) {
+ /* One sample left to process */
+ nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
+ nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
+ }
+
+ /* Make sure to have at least one extra leading zero (two leading zeros in total) */
+ if( nrg & 0xC0000000 ) {
+ nrg = silk_RSHIFT_uint( (opus_uint32)nrg, 2 );
+ shft += 2;
+ }
+
+ /* Output arguments */
+ *shift = shft;
+ *energy = nrg;
+}
+