tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/MatrixFunctions/arm_mat_mult_fast_q15.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:            arm_mat_mult_fast_q15.c
   9 *
  10 * Description:   Q15 matrix multiplication (fast variant)
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * -------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupMatrix
  45  */
  46
  47 /**
  48  * @addtogroup MatrixMult
  49  * @{
  50  */
  51
  52
  53 /**
  54  * @brief Q15 matrix multiplication (fast variant) for Cortex-M3 and Cortex-M4
  55  * @param[in]       *pSrcA points to the first input matrix structure
  56  * @param[in]       *pSrcB points to the second input matrix structure
  57  * @param[out]      *pDst points to output matrix structure
  58  * @param[in]           *pState points to the array for storing intermediate results
  59  * @return              The function returns either
  60  * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
  61  *
  62  * @details
  63  * <b>Scaling and Overflow Behavior:</b>
  64  *
  65  * \par
  66  * The difference between the function arm_mat_mult_q15() and this fast variant is that
  67  * the fast variant use a 32-bit rather than a 64-bit accumulator.
  68  * The result of each 1.15 x 1.15 multiplication is truncated to
  69  * 2.30 format. These intermediate results are accumulated in a 32-bit register in 2.30
  70  * format. Finally, the accumulator is saturated and converted to a 1.15 result.
  71  *
  72  * \par
  73  * The fast version has the same overflow behavior as the standard version but provides
  74  * less precision since it discards the low 16 bits of each multiplication result.
  75  * In order to avoid overflows completely the input signals must be scaled down.
  76  * Scale down one of the input matrices by log2(numColsA) bits to
  77  * avoid overflows, as a total of numColsA additions are computed internally for each
  78  * output element.
  79  *
  80  * \par
  81  * See <code>arm_mat_mult_q15()</code> for a slower implementation of this function
  82  * which uses 64-bit accumulation to provide higher precision.
  83  */
  84
  85 arm_status arm_mat_mult_fast_q15(
  86   const arm_matrix_instance_q15 * pSrcA,
  87   const arm_matrix_instance_q15 * pSrcB,
  88   arm_matrix_instance_q15 * pDst,
  89   q15_t * pState)
  90 {
  91   q31_t sum;                                     /* accumulator */
  92   q15_t *pSrcBT = pState;                        /* input data matrix pointer for transpose */
  93   q15_t *pInA = pSrcA->pData;                    /* input data matrix pointer A of Q15 type */
  94   q15_t *pInB = pSrcB->pData;                    /* input data matrix pointer B of Q15 type */
  95   q15_t *px;                                     /* Temporary output data matrix pointer */
  96   uint16_t numRowsA = pSrcA->numRows;            /* number of rows of input matrix A    */
  97   uint16_t numColsB = pSrcB->numCols;            /* number of columns of input matrix B */
  98   uint16_t numColsA = pSrcA->numCols;            /* number of columns of input matrix A */
  99   uint16_t numRowsB = pSrcB->numRows;            /* number of rows of input matrix A    */
 100   uint16_t col, i = 0u, row = numRowsB, colCnt;  /* loop counters */
 101   arm_status status;                             /* status of matrix multiplication */
 102
 103 #ifndef UNALIGNED_SUPPORT_DISABLE
 104
 105   q31_t in;                                      /* Temporary variable to hold the input value */
 106   q31_t inA1, inA2, inB1, inB2;
 107
 108 #else
 109
 110   q15_t in;                                      /* Temporary variable to hold the input value */
 111   q15_t inA1, inA2, inB1, inB2;
 112
 113 #endif  /*      #ifndef UNALIGNED_SUPPORT_DISABLE       */
 114
 115 #ifdef ARM_MATH_MATRIX_CHECK
 116   /* Check for matrix mismatch condition */
 117   if((pSrcA->numCols != pSrcB->numRows) ||
 118      (pSrcA->numRows != pDst->numRows) || (pSrcB->numCols != pDst->numCols))
 119   {
 120     /* Set status as ARM_MATH_SIZE_MISMATCH */
 121     status = ARM_MATH_SIZE_MISMATCH;
 122   }
 123   else
 124 #endif
 125   {
 126     /* Matrix transpose */
 127     do
 128     {
 129       /* Apply loop unrolling and exchange the columns with row elements */
 130       col = numColsB >> 2;
 131
 132       /* The pointer px is set to starting address of the column being processed */
 133       px = pSrcBT + i;
 134
 135       /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
 136        ** a second loop below computes the remaining 1 to 3 samples. */
 137       while(col > 0u)
 138       {
 139 #ifndef UNALIGNED_SUPPORT_DISABLE
 140         /* Read two elements from the row */
 141         in = *__SIMD32(pInB)++;
 142
 143         /* Unpack and store one element in the destination */
 144 #ifndef ARM_MATH_BIG_ENDIAN
 145
 146         *px = (q15_t) in;
 147
 148 #else
 149
 150         *px = (q15_t) ((in & (q31_t) 0xffff0000) >> 16);
 151
 152 #endif /*    #ifndef ARM_MATH_BIG_ENDIAN    */
 153
 154         /* Update the pointer px to point to the next row of the transposed matrix */
 155         px += numRowsB;
 156
 157         /* Unpack and store the second element in the destination */
 158 #ifndef ARM_MATH_BIG_ENDIAN
 159
 160         *px = (q15_t) ((in & (q31_t) 0xffff0000) >> 16);
 161
 162 #else
 163
 164         *px = (q15_t) in;
 165
 166 #endif /*    #ifndef ARM_MATH_BIG_ENDIAN    */
 167
 168         /* Update the pointer px to point to the next row of the transposed matrix */
 169         px += numRowsB;
 170
 171         /* Read two elements from the row */
 172         in = *__SIMD32(pInB)++;
 173
 174         /* Unpack and store one element in the destination */
 175 #ifndef ARM_MATH_BIG_ENDIAN
 176
 177         *px = (q15_t) in;
 178
 179 #else
 180
 181         *px = (q15_t) ((in & (q31_t) 0xffff0000) >> 16);
 182
 183 #endif /*    #ifndef ARM_MATH_BIG_ENDIAN    */
 184
 185         /* Update the pointer px to point to the next row of the transposed matrix */
 186         px += numRowsB;
 187
 188         /* Unpack and store the second element in the destination */
 189
 190 #ifndef ARM_MATH_BIG_ENDIAN
 191
 192         *px = (q15_t) ((in & (q31_t) 0xffff0000) >> 16);
 193
 194 #else
 195
 196         *px = (q15_t) in;
 197
 198 #endif /*    #ifndef ARM_MATH_BIG_ENDIAN    */
 199
 200 #else
 201
 202         /* Read one element from the row */
 203         in = *pInB++;
 204
 205         /* Store one element in the destination */
 206         *px = in;
 207
 208         /* Update the pointer px to point to the next row of the transposed matrix */
 209         px += numRowsB;
 210
 211         /* Read one element from the row */
 212         in = *pInB++;
 213
 214         /* Store one element in the destination */
 215         *px = in;
 216
 217         /* Update the pointer px to point to the next row of the transposed matrix */
 218         px += numRowsB;
 219
 220         /* Read one element from the row */
 221         in = *pInB++;
 222
 223         /* Store one element in the destination */
 224         *px = in;
 225
 226         /* Update the pointer px to point to the next row of the transposed matrix */
 227         px += numRowsB;
 228
 229         /* Read one element from the row */
 230         in = *pInB++;
 231
 232         /* Store one element in the destination */
 233         *px = in;
 234
 235 #endif  /*      #ifndef UNALIGNED_SUPPORT_DISABLE       */
 236
 237                 /* Update the pointer px to point to the next row of the transposed matrix */
 238         px += numRowsB;
 239
 240         /* Decrement the column loop counter */
 241         col--;
 242       }
 243
 244       /* If the columns of pSrcB is not a multiple of 4, compute any remaining output samples here.
 245        ** No loop unrolling is used. */
 246       col = numColsB % 0x4u;
 247
 248       while(col > 0u)
 249       {
 250         /* Read and store the input element in the destination */
 251         *px = *pInB++;
 252
 253         /* Update the pointer px to point to the next row of the transposed matrix */
 254         px += numRowsB;
 255
 256         /* Decrement the column loop counter */
 257         col--;
 258       }
 259
 260       i++;
 261
 262       /* Decrement the row loop counter */
 263       row--;
 264
 265     } while(row > 0u);
 266
 267     /* Reset the variables for the usage in the following multiplication process */
 268     row = numRowsA;
 269     i = 0u;
 270     px = pDst->pData;
 271
 272     /* The following loop performs the dot-product of each row in pSrcA with each column in pSrcB */
 273     /* row loop */
 274     do
 275     {
 276       /* For every row wise process, the column loop counter is to be initiated */
 277       col = numColsB;
 278
 279       /* For every row wise process, the pIn2 pointer is set
 280        ** to the starting address of the transposed pSrcB data */
 281       pInB = pSrcBT;
 282
 283       /* column loop */
 284       do
 285       {
 286         /* Set the variable sum, that acts as accumulator, to zero */
 287         sum = 0;
 288
 289         /* Apply loop unrolling and compute 2 MACs simultaneously. */
 290         colCnt = numColsA >> 2;
 291
 292         /* Initiate the pointer pIn1 to point to the starting address of the column being processed */
 293         pInA = pSrcA->pData + i;
 294
 295         /* matrix multiplication */
 296         while(colCnt > 0u)
 297         {
 298           /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */
 299 #ifndef UNALIGNED_SUPPORT_DISABLE
 300
 301           inA1 = *__SIMD32(pInA)++;
 302           inB1 = *__SIMD32(pInB)++;
 303           inA2 = *__SIMD32(pInA)++;
 304           inB2 = *__SIMD32(pInB)++;
 305
 306           sum = __SMLAD(inA1, inB1, sum);
 307           sum = __SMLAD(inA2, inB2, sum);
 308
 309 #else
 310
 311           inA1 = *pInA++;
 312           inB1 = *pInB++;
 313           inA2 = *pInA++;
 314           sum += inA1 * inB1;
 315           inB2 = *pInB++;
 316
 317           inA1 = *pInA++;
 318           inB1 = *pInB++;
 319           sum += inA2 * inB2;
 320           inA2 = *pInA++;
 321           inB2 = *pInB++;
 322
 323           sum += inA1 * inB1;
 324           sum += inA2 * inB2;
 325
 326 #endif  /*      #ifndef UNALIGNED_SUPPORT_DISABLE       */
 327
 328           /* Decrement the loop counter */
 329           colCnt--;
 330         }
 331
 332         /* process odd column samples */
 333         colCnt = numColsA % 0x4u;
 334
 335         while(colCnt > 0u)
 336         {
 337           /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */
 338           sum += (q31_t) (*pInA++) * (*pInB++);
 339
 340           colCnt--;
 341         }
 342
 343         /* Saturate and store the result in the destination buffer */
 344         *px = (q15_t) (sum >> 15);
 345         px++;
 346
 347         /* Decrement the column loop counter */
 348         col--;
 349
 350       } while(col > 0u);
 351
 352       i = i + numColsA;
 353
 354       /* Decrement the row loop counter */
 355       row--;
 356
 357     } while(row > 0u);
 358
 359     /* set status as ARM_MATH_SUCCESS */
 360     status = ARM_MATH_SUCCESS;
 361   }
 362
 363   /* Return to application */
 364   return (status);
 365 }
 366
 367 /**
 368  * @} end of MatrixMult group
 369  */