Diff: src/Cortex-M4-M3/MatrixFunctions/arm_mat_mult_fast_q31.c

Revision:

0:1014af42efd9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Cortex-M4-M3/MatrixFunctions/arm_mat_mult_fast_q31.c	Thu Mar 10 15:07:50 2011 +0000
@@ -0,0 +1,196 @@
+/* ----------------------------------------------------------------------  
+* Copyright (C) 2010 ARM Limited. All rights reserved.  
+*  
+* $Date:        29. November 2010  
+* $Revision: 	V1.0.3  
+*  
+* Project: 	    CMSIS DSP Library  
+* Title:	    arm_mat_mult_fast_q31.c  
+*  
+* Description:	 Q31 matrix multiplication (fast variant).  
+*  
+* Target Processor: Cortex-M4/Cortex-M3
+*  
+* Version 1.0.3 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)  
+ * @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 */ 
+ 
+ 
+#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 
+  { 
+    /* 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 */ 
+          sum = (q31_t) ((((q63_t) sum << 32) + 
+                          ((q63_t) * pIn1++ * (*pIn2))) >> 32); 
+          pIn2 += numColsB; 
+          sum = (q31_t) ((((q63_t) sum << 32) + 
+                          ((q63_t) * pIn1++ * (*pIn2))) >> 32); 
+          pIn2 += numColsB; 
+          sum = (q31_t) ((((q63_t) sum << 32) + 
+                          ((q63_t) * pIn1++ * (*pIn2))) >> 32); 
+          pIn2 += numColsB; 
+          sum = (q31_t) ((((q63_t) sum << 32) + 
+                          ((q63_t) * pIn1++ * (*pIn2))) >> 32); 
+          pIn2 += numColsB; 
+ 
+          /* 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  
+ */