Diff: DSP/source/BasicMathFunctions/arm_sub_f32.c

Revision:

0:eedb7d567a5d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DSP/source/BasicMathFunctions/arm_sub_f32.c	Thu Apr 12 01:31:58 2018 +0000
@@ -0,0 +1,139 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_sub_f32.c
+ * Description:  Floating-point vector subtraction.
+ *
+ * $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 groupMath
+ */
+
+/**
+ * @defgroup BasicSub Vector Subtraction
+ *
+ * Element-by-element subtraction of two vectors.
+ *
+ * <pre>
+ *     pDst[n] = pSrcA[n] - pSrcB[n],   0 <= n < blockSize.
+ * </pre>
+ *
+ * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
+ */
+
+/**
+ * @addtogroup BasicSub
+ * @{
+ */
+
+
+/**
+ * @brief Floating-point vector subtraction.
+ * @param[in]       *pSrcA points to the first input vector
+ * @param[in]       *pSrcB points to the second input vector
+ * @param[out]      *pDst points to the output vector
+ * @param[in]       blockSize number of samples in each vector
+ * @return none.
+ */
+
+void arm_sub_f32(
+  float32_t * pSrcA,
+  float32_t * pSrcB,
+  float32_t * pDst,
+  uint32_t blockSize)
+{
+  uint32_t blkCnt;                               /* loop counter */
+
+#if defined (ARM_MATH_DSP)
+
+/* Run the below code for Cortex-M4 and Cortex-M3 */
+  float32_t inA1, inA2, inA3, inA4;              /* temporary variables */
+  float32_t inB1, inB2, inB3, inB4;              /* temporary variables */
+
+  /*loop Unrolling */
+  blkCnt = blockSize >> 2U;
+
+  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
+   ** a second loop below computes the remaining 1 to 3 samples. */
+  while (blkCnt > 0U)
+  {
+    /* C = A - B */
+    /* Subtract and then store the results in the destination buffer. */
+    /* Read 4 input samples from sourceA and sourceB */
+    inA1 = *pSrcA;
+    inB1 = *pSrcB;
+    inA2 = *(pSrcA + 1);
+    inB2 = *(pSrcB + 1);
+    inA3 = *(pSrcA + 2);
+    inB3 = *(pSrcB + 2);
+    inA4 = *(pSrcA + 3);
+    inB4 = *(pSrcB + 3);
+
+    /* dst = srcA - srcB */
+    /* subtract and store the result */
+    *pDst = inA1 - inB1;
+    *(pDst + 1) = inA2 - inB2;
+    *(pDst + 2) = inA3 - inB3;
+    *(pDst + 3) = inA4 - inB4;
+
+
+    /* Update pointers to process next sampels */
+    pSrcA += 4U;
+    pSrcB += 4U;
+    pDst += 4U;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
+   ** No loop unrolling is used. */
+  blkCnt = blockSize % 0x4U;
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* Initialize blkCnt with number of samples */
+  blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+  while (blkCnt > 0U)
+  {
+    /* C = A - B */
+    /* Subtract and then store the results in the destination buffer. */
+    *pDst++ = (*pSrcA++) - (*pSrcB++);
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+}
+
+/**
+ * @} end of BasicSub group
+ */
+