Diff: DSP/source/StatisticsFunctions/arm_max_q15.c

Revision:

0:eedb7d567a5d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DSP/source/StatisticsFunctions/arm_max_q15.c	Thu Apr 12 01:31:58 2018 +0000
@@ -0,0 +1,163 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_max_q15.c
+ * Description:  Maximum value of a Q15 vector
+ *
+ * $Date:        27. January 2017
+ * $Revision:    V.1.5.1
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+
+/**
+ * @ingroup groupStats
+ */
+
+/**
+ * @addtogroup Max
+ * @{
+ */
+
+
+/**
+ * @brief Maximum value of a Q15 vector.
+ * @param[in]       *pSrc points to the input vector
+ * @param[in]       blockSize length of the input vector
+ * @param[out]      *pResult maximum value returned here
+ * @param[out]      *pIndex index of maximum value returned here
+ * @return none.
+ */
+
+void arm_max_q15(
+  q15_t * pSrc,
+  uint32_t blockSize,
+  q15_t * pResult,
+  uint32_t * pIndex)
+{
+#if defined (ARM_MATH_DSP)
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  q15_t maxVal1, maxVal2, out;                   /* Temporary variables to store the output value. */
+  uint32_t blkCnt, outIndex, count;              /* loop counter */
+
+  /* Initialise the count value. */
+  count = 0U;
+  /* Initialise the index value to zero. */
+  outIndex = 0U;
+  /* Load first input value that act as reference value for comparision */
+  out = *pSrc++;
+
+  /* Loop unrolling */
+  blkCnt = (blockSize - 1U) >> 2U;
+
+  while (blkCnt > 0U)
+  {
+    /* Initialize maxVal to the next consecutive values one by one */
+    maxVal1 = *pSrc++;
+    maxVal2 = *pSrc++;
+
+    /* compare for the maximum value */
+    if (out < maxVal1)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal1;
+      outIndex = count + 1U;
+    }
+
+    /* compare for the maximum value */
+    if (out < maxVal2)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal2;
+      outIndex = count + 2U;
+    }
+
+    /* Initialize maxVal to the next consecutive values one by one */
+    maxVal1 = *pSrc++;
+    maxVal2 = *pSrc++;
+
+    /* compare for the maximum value */
+    if (out < maxVal1)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal1;
+      outIndex = count + 3U;
+    }
+
+    /* compare for the maximum value */
+    if (out < maxVal2)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal2;
+      outIndex = count + 4U;
+    }
+
+    count += 4U;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* if (blockSize - 1U) is not multiple of 4 */
+  blkCnt = (blockSize - 1U) % 4U;
+
+#else
+  /* Run the below code for Cortex-M0 */
+
+  q15_t maxVal1, out;                            /* Temporary variables to store the output value. */
+  uint32_t blkCnt, outIndex;                     /* loop counter */
+
+  /* Initialise the index value to zero. */
+  outIndex = 0U;
+  /* Load first input value that act as reference value for comparision */
+  out = *pSrc++;
+
+  blkCnt = (blockSize - 1U);
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+  while (blkCnt > 0U)
+  {
+    /* Initialize maxVal to the next consecutive values one by one */
+    maxVal1 = *pSrc++;
+
+    /* compare for the maximum value */
+    if (out < maxVal1)
+    {
+      /* Update the maximum value and it's index */
+      out = maxVal1;
+      outIndex = blockSize - blkCnt;
+    }
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Store the maximum value and it's index into destination pointers */
+  *pResult = out;
+  *pIndex = outIndex;
+}
+
+/**
+ * @} end of Max group
+ */
+