Diff: SupportFunctions/arm_float_to_q31.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SupportFunctions/arm_float_to_q31.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,211 @@
+/* ----------------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014 
+* $Revision: 	V1.4.3  
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:		arm_float_to_q31.c    
+*    
+* Description:	Converts the elements of the floating-point vector to Q31 vector.    
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Redistribution and use in source and binary forms, with or without 
+* modification, are permitted provided that the following conditions
+* are met:
+*   - Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*   - Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in
+*     the documentation and/or other materials provided with the 
+*     distribution.
+*   - Neither the name of ARM LIMITED nor the names of its contributors
+*     may be used to endorse or promote products derived from this
+*     software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.  
+* ---------------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupSupport    
+ */
+
+/**    
+ * @defgroup float_to_x  Convert 32-bit floating point value    
+ */
+
+/**    
+ * @addtogroup float_to_x    
+ * @{    
+ */
+
+/**    
+ * @brief Converts the elements of the floating-point vector to Q31 vector.    
+ * @param[in]       *pSrc points to the floating-point input vector    
+ * @param[out]      *pDst points to the Q31 output vector   
+ * @param[in]       blockSize length of the input vector    
+ * @return none.    
+ *    
+ *\par Description:    
+ * \par   
+ * The equation used for the conversion process is:    
+ *   
+ * <pre>    
+ * 	pDst[n] = (q31_t)(pSrc[n] * 2147483648);   0 <= n < blockSize.    
+ * </pre>    
+ * <b>Scaling and Overflow Behavior:</b>    
+ * \par    
+ * The function uses saturating arithmetic.    
+ * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.    
+ *   
+ * \note In order to apply rounding, the library should be rebuilt with the ROUNDING macro     
+ * defined in the preprocessor section of project options.     
+ */
+
+
+void arm_float_to_q31(
+  float32_t * pSrc,
+  q31_t * pDst,
+  uint32_t blockSize)
+{
+  float32_t *pIn = pSrc;                         /* Src pointer */
+  uint32_t blkCnt;                               /* loop counter */
+
+#ifdef ARM_MATH_ROUNDING
+
+  float32_t in;
+
+#endif /*      #ifdef ARM_MATH_ROUNDING        */
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  /*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)
+  {
+
+#ifdef ARM_MATH_ROUNDING
+
+    /* C = A * 32768 */
+    /* convert from float to Q31 and then store the results in the destination buffer */
+    in = *pIn++;
+    in = (in * 2147483648.0f);
+    in += in > 0 ? 0.5 : -0.5;
+    *pDst++ = clip_q63_to_q31((q63_t) (in));
+
+    in = *pIn++;
+    in = (in * 2147483648.0f);
+    in += in > 0 ? 0.5 : -0.5;
+    *pDst++ = clip_q63_to_q31((q63_t) (in));
+
+    in = *pIn++;
+    in = (in * 2147483648.0f);
+    in += in > 0 ? 0.5 : -0.5;
+    *pDst++ = clip_q63_to_q31((q63_t) (in));
+
+    in = *pIn++;
+    in = (in * 2147483648.0f);
+    in += in > 0 ? 0.5 : -0.5;
+    *pDst++ = clip_q63_to_q31((q63_t) (in));
+
+#else
+
+    /* C = A * 2147483648 */
+    /* convert from float to Q31 and then store the results in the destination buffer */
+    *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
+    *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
+    *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
+    *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
+
+#endif /*      #ifdef ARM_MATH_ROUNDING        */
+
+    /* 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;
+
+  while(blkCnt > 0u)
+  {
+
+#ifdef ARM_MATH_ROUNDING
+
+    /* C = A * 2147483648 */
+    /* convert from float to Q31 and then store the results in the destination buffer */
+    in = *pIn++;
+    in = (in * 2147483648.0f);
+    in += in > 0 ? 0.5 : -0.5;
+    *pDst++ = clip_q63_to_q31((q63_t) (in));
+
+#else
+
+    /* C = A * 2147483648 */
+    /* convert from float to Q31 and then store the results in the destination buffer */
+    *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
+
+#endif /*      #ifdef ARM_MATH_ROUNDING        */
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* Loop over blockSize number of values */
+  blkCnt = blockSize;
+
+  while(blkCnt > 0u)
+  {
+
+#ifdef ARM_MATH_ROUNDING
+
+    /* C = A * 2147483648 */
+    /* convert from float to Q31 and then store the results in the destination buffer */
+    in = *pIn++;
+    in = (in * 2147483648.0f);
+    in += in > 0 ? 0.5f : -0.5f;
+    *pDst++ = clip_q63_to_q31((q63_t) (in));
+
+#else
+
+    /* C = A * 2147483648 */
+    /* convert from float to Q31 and then store the results in the destination buffer */
+    *pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
+
+#endif /*      #ifdef ARM_MATH_ROUNDING        */
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+#endif /* #ifndef ARM_MATH_CM0_FAMILY */
+
+}
+
+/**    
+ * @} end of float_to_x group    
+ */