Diff: cmsis_dsp/MatrixFunctions/arm_mat_mult_fast_q31.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/MatrixFunctions/arm_mat_mult_fast_q31.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,218 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_mat_mult_fast_q31.c    
+*    
+* Description:     Q31 matrix multiplication (fast variant).    
+*    
+* Target Processor: Cortex-M4/Cortex-M3
+*  
+* Version 1.1.0 2012/02/15 
+*    Updated with more optimizations, bug fixes and minor API changes.  
+*   
+* Version 1.0.10 2011/7/15  
+*    Big Endian support added and Merged M0 and M3/M4 Source code.   
+*    
+* Version 1.0.3 2010/11/29   
+*    Re-organized the CMSIS folders and updated documentation.    
+*     
+* Version 1.0.2 2010/11/11    
+*    Documentation updated.     
+*    
+* Version 1.0.1 2010/10/05     
+*    Production release and review comments incorporated.    
+*    
+* Version 1.0.0 2010/09/20     
+*    Production release and review comments incorporated.    
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupMatrix    
+ */
+
+/**    
+ * @addtogroup MatrixMult    
+ * @{    
+ */
+
+/**    
+ * @brief Q31 matrix multiplication (fast variant) for Cortex-M3 and Cortex-M4    
+ * @param[in]       *pSrcA points to the first input matrix structure    
+ * @param[in]       *pSrcB points to the second input matrix structure    
+ * @param[out]      *pDst points to output matrix structure    
+ * @return             The function returns either    
+ * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.    
+ *    
+ * @details    
+ * <b>Scaling and Overflow Behavior:</b>    
+ *    
+ * \par    
+ * The difference between the function arm_mat_mult_q31() and this fast variant is that    
+ * the fast variant use a 32-bit rather than a 64-bit accumulator.    
+ * The result of each 1.31 x 1.31 multiplication is truncated to    
+ * 2.30 format. These intermediate results are accumulated in a 32-bit register in 2.30    
+ * format. Finally, the accumulator is saturated and converted to a 1.31 result.    
+ *    
+ * \par    
+ * The fast version has the same overflow behavior as the standard version but provides    
+ * less precision since it discards the low 32 bits of each multiplication result.    
+ * In order to avoid overflows completely the input signals must be scaled down.    
+ * Scale down one of the input matrices by log2(numColsA) bits to    
+ * avoid overflows, as a total of numColsA additions are computed internally for each    
+ * output element.    
+ *    
+ * \par    
+ * See <code>arm_mat_mult_q31()</code> for a slower implementation of this function    
+ * which uses 64-bit accumulation to provide higher precision.    
+ */
+
+arm_status arm_mat_mult_fast_q31(
+  const arm_matrix_instance_q31 * pSrcA,
+  const arm_matrix_instance_q31 * pSrcB,
+  arm_matrix_instance_q31 * pDst)
+{
+  q31_t *pIn1 = pSrcA->pData;                    /* input data matrix pointer A */
+  q31_t *pIn2 = pSrcB->pData;                    /* input data matrix pointer B */
+  q31_t *pInA = pSrcA->pData;                    /* input data matrix pointer A */
+//  q31_t *pSrcB = pSrcB->pData;                    /* input data matrix pointer B */    
+  q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
+  q31_t *px;                                     /* Temporary output data matrix pointer */
+  q31_t sum;                                     /* Accumulator */
+  uint16_t numRowsA = pSrcA->numRows;            /* number of rows of input matrix A    */
+  uint16_t numColsB = pSrcB->numCols;            /* number of columns of input matrix B */
+  uint16_t numColsA = pSrcA->numCols;            /* number of columns of input matrix A */
+  uint16_t col, i = 0u, j, row = numRowsA, colCnt;      /* loop counters */
+  arm_status status;                             /* status of matrix multiplication */
+  q31_t inA1, inA2, inA3, inA4, inB1, inB2, inB3, inB4;
+
+#ifdef ARM_MATH_MATRIX_CHECK
+
+
+  /* Check for matrix mismatch condition */
+  if((pSrcA->numCols != pSrcB->numRows) ||
+     (pSrcA->numRows != pDst->numRows) || (pSrcB->numCols != pDst->numCols))
+  {
+    /* Set status as ARM_MATH_SIZE_MISMATCH */
+    status = ARM_MATH_SIZE_MISMATCH;
+  }
+  else
+#endif /*      #ifdef ARM_MATH_MATRIX_CHECK    */
+
+  {
+    /* The following loop performs the dot-product of each row in pSrcA with each column in pSrcB */
+    /* row loop */
+    do
+    {
+      /* Output pointer is set to starting address of the row being processed */
+      px = pOut + i;
+
+      /* For every row wise process, the column loop counter is to be initiated */
+      col = numColsB;
+
+      /* For every row wise process, the pIn2 pointer is set    
+       ** to the starting address of the pSrcB data */
+      pIn2 = pSrcB->pData;
+
+      j = 0u;
+
+      /* column loop */
+      do
+      {
+        /* Set the variable sum, that acts as accumulator, to zero */
+        sum = 0;
+
+        /* Initiate the pointer pIn1 to point to the starting address of pInA */
+        pIn1 = pInA;
+
+        /* Apply loop unrolling and compute 4 MACs simultaneously. */
+        colCnt = numColsA >> 2;
+
+
+        /* matrix multiplication */
+        while(colCnt > 0u)
+        {
+          /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */
+          /* Perform the multiply-accumulates */
+          inB1 = *pIn2;
+          pIn2 += numColsB;
+
+          inA1 = pIn1[0];
+          inA2 = pIn1[1];
+
+          inB2 = *pIn2;
+          pIn2 += numColsB;
+
+          inB3 = *pIn2;
+          pIn2 += numColsB;
+
+          sum = (q31_t) ((((q63_t) sum << 32) + ((q63_t) inA1 * inB1)) >> 32);
+          sum = (q31_t) ((((q63_t) sum << 32) + ((q63_t) inA2 * inB2)) >> 32);
+
+          inA3 = pIn1[2];
+          inA4 = pIn1[3];
+
+          inB4 = *pIn2;
+          pIn2 += numColsB;
+
+          sum = (q31_t) ((((q63_t) sum << 32) + ((q63_t) inA3 * inB3)) >> 32);
+          sum = (q31_t) ((((q63_t) sum << 32) + ((q63_t) inA4 * inB4)) >> 32);
+
+          pIn1 += 4u;
+
+          /* Decrement the loop counter */
+          colCnt--;
+        }
+
+        /* If the columns of pSrcA is not a multiple of 4, compute any remaining output samples here.    
+         ** No loop unrolling is used. */
+        colCnt = numColsA % 0x4u;
+
+        while(colCnt > 0u)
+        {
+          /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */
+          /* Perform the multiply-accumulates */
+          sum = (q31_t) ((((q63_t) sum << 32) +
+                          ((q63_t) * pIn1++ * (*pIn2))) >> 32);
+          pIn2 += numColsB;
+
+          /* Decrement the loop counter */
+          colCnt--;
+        }
+
+        /* Convert the result from 2.30 to 1.31 format and store in destination buffer */
+        *px++ = sum << 1;
+
+        /* Update the pointer pIn2 to point to the  starting address of the next column */
+        j++;
+        pIn2 = pSrcB->pData + j;
+
+        /* Decrement the column loop counter */
+        col--;
+
+      } while(col > 0u);
+
+      /* Update the pointer pInA to point to the  starting address of the next row */
+      i = i + numColsB;
+      pInA = pInA + numColsA;
+
+      /* Decrement the row loop counter */
+      row--;
+
+    } while(row > 0u);
+
+    /* set status as ARM_MATH_SUCCESS */
+    status = ARM_MATH_SUCCESS;
+  }
+  /* Return to application */
+  return (status);
+}
+
+/**    
+ * @} end of MatrixMult group    
+ */