Renesas
Fork of mbed-dsp. CMSIS-DSP library of supporting NEON
Dependents: mbed-os-example-cmsis_dsp_neon
Fork of
mbed-dsp
by 
mbed official
Information
Japanese version is available in lower part of this page.
このページの後半に日本語版が用意されています．
CMSIS-DSP of supporting NEON
What is this ?
A library for CMSIS-DSP of supporting NEON.
We supported the NEON to CMSIS-DSP Ver1.4.3(CMSIS V4.1) that ARM supplied, has achieved the processing speed improvement.
If you use the mbed-dsp library, you can use to replace this library.
CMSIS-DSP of supporting NEON is provied as a library.
Library Creation environment
CMSIS-DSP library of supporting NEON was created by the following environment.
- Compiler
ARMCC Version 5.03 - Compile option switch[C Compiler]
-DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -O3 -Otime --cpu=Cortex-A9 --littleend --arm --apcs=/interwork --no_unaligned_access --fpu=vfpv3_fp16 --fpmode=fast --apcs=/hardfp --vectorize --asm
- Compile option switch[Assembler]
--cpreproc --cpu=Cortex-A9 --littleend --arm --apcs=/interwork --no_unaligned_access --fpu=vfpv3_fp16 --fpmode=fast --apcs=/hardfp
Effects of NEON support
In the data which passes to each function, large size will be expected more effective than small size.
Also if the data is a multiple of 16, effect will be expected in every function in the CMSIS-DSP.
NEON対応CMSIS-DSP
概要
NEON対応したCMSIS-DSPのライブラリです。
ARM社提供のCMSIS-DSP Ver1.4.3(CMSIS V4.1)をターゲットにNEON対応を行ない、処理速度向上を実現しております。
mbed-dspライブラリを使用している場合は、本ライブラリに置き換えて使用することができます。
NEON対応したCMSIS-DSPはライブラリで提供します。
ライブラリ作成環境
NEON対応CMSIS-DSPライブラリは、以下の環境で作成しています。
- コンパイラ
ARMCC Version 5.03 - コンパイルオプションスイッチ[C Compiler]
-DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -O3 -Otime --cpu=Cortex-A9 --littleend --arm --apcs=/interwork --no_unaligned_access --fpu=vfpv3_fp16 --fpmode=fast --apcs=/hardfp --vectorize --asm
- コンパイルオプションスイッチ[Assembler]
--cpreproc --cpu=Cortex-A9 --littleend --arm --apcs=/interwork --no_unaligned_access --fpu=vfpv3_fp16 --fpmode=fast --apcs=/hardfp
NEON対応による効果について
CMSIS-DSP内の各関数へ渡すデータは、小さいサイズよりも大きいサイズの方が効果が見込めます。
また、16の倍数のデータであれば、CMSIS-DSP内のどの関数でも効果が見込めます。
Diff: cmsis_dsp/FastMathFunctions/arm_sqrt_q15.c
- Revision:
- 1:fdd22bb7aa52
- Child:
- 2:da51fb522205
diff -r 83d0537c7d84 -r fdd22bb7aa52 cmsis_dsp/FastMathFunctions/arm_sqrt_q15.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FastMathFunctions/arm_sqrt_q15.c Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,131 @@
+/* ----------------------------------------------------------------------
+* Copyright (C) 2011 ARM Limited. All rights reserved.
+*
+* $Date: 15. February 2012
+* $Revision: V1.1.0
+*
+* Project: CMSIS DSP Library
+* Title: arm_sqrt_q15.c
+*
+* Description: Q15 square root function.
+*
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*
+* Version 1.1.0 2012/02/15
+* Updated with more optimizations, bug fixes and minor API changes.
+*
+* Version 1.0.0 2011/03/08
+* Alpha release.
+*
+* Version 1.0.1 2011/09/30
+* Beta release.
+*
+* -------------------------------------------------------------------- */
+#include "arm_math.h"
+#include "arm_common_tables.h"
+
+
+/**
+ * @ingroup groupFastMath
+ */
+
+/**
+ * @addtogroup SQRT
+ * @{
+ */
+
+ /**
+ * @brief Q15 square root function.
+ * @param[in] in input value. The range of the input value is [0 +1) or 0x0000 to 0x7FFF.
+ * @param[out] *pOut square root of input value.
+ * @return The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if
+ * <code>in</code> is negative value and returns zero output for negative values.
+ */
+
+arm_status arm_sqrt_q15(
+ q15_t in,
+ q15_t * pOut)
+{
+ q15_t number, temp1, var1, signBits1, half;
+ q31_t bits_val1;
+ float32_t temp_float1;
+
+ number = in;
+
+ /* If the input is a positive number then compute the signBits. */
+ if(number > 0)
+ {
+ signBits1 = __CLZ(number) - 17;
+
+ /* Shift by the number of signBits1 */
+ if((signBits1 % 2) == 0)
+ {
+ number = number << signBits1;
+ }
+ else
+ {
+ number = number << (signBits1 - 1);
+ }
+
+ /* Calculate half value of the number */
+ half = number >> 1;
+ /* Store the number for later use */
+ temp1 = number;
+
+ /*Convert to float */
+ temp_float1 = number * 3.051757812500000e-005f;
+ /*Store as integer */
+ bits_val1 = *(int *) &temp_float1;
+ /* Subtract the shifted value from the magic number to give intial guess */
+ bits_val1 = 0x5f3759df - (bits_val1 >> 1); // gives initial guess
+ /* Store as float */
+ temp_float1 = *(float *) &bits_val1;
+ /* Convert to integer format */
+ var1 = (q31_t) (temp_float1 * 16384);
+
+ /* 1st iteration */
+ var1 = ((q15_t) ((q31_t) var1 * (0x3000 -
+ ((q15_t)
+ ((((q15_t)
+ (((q31_t) var1 * var1) >> 15)) *
+ (q31_t) half) >> 15))) >> 15)) << 2;
+ /* 2nd iteration */
+ var1 = ((q15_t) ((q31_t) var1 * (0x3000 -
+ ((q15_t)
+ ((((q15_t)
+ (((q31_t) var1 * var1) >> 15)) *
+ (q31_t) half) >> 15))) >> 15)) << 2;
+ /* 3rd iteration */
+ var1 = ((q15_t) ((q31_t) var1 * (0x3000 -
+ ((q15_t)
+ ((((q15_t)
+ (((q31_t) var1 * var1) >> 15)) *
+ (q31_t) half) >> 15))) >> 15)) << 2;
+
+ /* Multiply the inverse square root with the original value */
+ var1 = ((q15_t) (((q31_t) temp1 * var1) >> 15)) << 1;
+
+ /* Shift the output down accordingly */
+ if((signBits1 % 2) == 0)
+ {
+ var1 = var1 >> (signBits1 / 2);
+ }
+ else
+ {
+ var1 = var1 >> ((signBits1 - 1) / 2);
+ }
+ *pOut = var1;
+
+ return (ARM_MATH_SUCCESS);
+ }
+ /* If the number is a negative number then store zero as its square root value */
+ else
+ {
+ *pOut = 0;
+ return (ARM_MATH_ARGUMENT_ERROR);
+ }
+}
+
+/**
+ * @} end of SQRT group
+ */