improve arm_correlate_q7 for CM0 (#178) (fd088ac7) · Commits · Wenxi XU / Cmsis Dsp

Source/FilteringFunctions/arm_correlate_q7.c

+6 −8

Original line number	Diff line number	Diff line
		@@ -921,7 +921,7 @@ void arm_correlate_q7(
		const q7_t pIn2 = pSrcB + (srcBLen - 1U); / InputB pointer */
		q31_t sum; /* Accumulator */
		uint32_t i = 0U, j; /* Loop counters */
		uint32_t inv = 0U; /* Reverse order flag */
		int32_t inc = 1; /* Destination address modifier */
		uint32_t tot = 0U; /* Length */

		/* The algorithm implementation is based on the lengths of the inputs. */
		@@ -929,7 +929,7 @@ void arm_correlate_q7(
		/* So srcBLen is always considered as shorter or equal to srcALen */
		/* But CORR(x, y) is reverse of CORR(y, x) */
		/* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
		/* and a varaible, inv is set to 1 */
		/* and a varaible, inc is set to -1 */
		/* If lengths are not equal then zero pad has to be done to make the two
		* inputs of same length. But to improve the performance, we include zeroes
		* in the output instead of zero padding either of the the inputs*/
		@@ -968,8 +968,8 @@ void arm_correlate_q7(
		srcALen = srcBLen;
		srcBLen = j;

		/* Setting the reverse flag */
		inv = 1;
		/* Filling destination in reverse order */
		inc = -1;
		}

		/* Loop to calculate convolution for output length number of times */
		@@ -990,10 +990,8 @@ void arm_correlate_q7(
		}

		/* Store the output in the destination buffer */
		if (inv == 1)
		*pDst-- = (q7_t) __SSAT((sum >> 7U), 8U);
		else
		*pDst++ = (q7_t) __SSAT((sum >> 7U), 8U);
		*pDst = (q7_t) __SSAT((sum >> 7U), 8U);
		pDst += inc;
		}

		#endif /* #if !defined(ARM_MATH_CM0_FAMILY) */