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Added Oplayer BSP, Fixed bug on GPIO library(gpiosetval change all the port...
Added Oplayer BSP, Fixed bug on GPIO library(gpiosetval change all the port instead of the desired bit).
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arm_sqrt_q15.c
178 lines | 5.3 KiB | text/x-c | CLexer
/ lib / src / stm32f4 / CPU / CMSIS / DSP_Lib / Source / FastMathFunctions / arm_sqrt_q15.c
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/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date: 15. July 2011
* $Revision: V1.0.10
*
* Project: CMSIS DSP Library
* Title: arm_sqrt_q15.c
*
* Description: Q15 square root function.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.0.10 2011/7/15
* Big Endian support added and Merged M0 and M3/M4 Source code.
*
* 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"
#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)
{
q31_t prevOut;
q15_t oneByOut;
uint32_t sign_bits;
#ifndef ARM_MATH_CM0
/* Run the below code for Cortex-M4 and Cortex-M3 */
q31_t out;
if(in > 0)
{
/* run for ten iterations */
/* Take initial guess as half of the input and first iteration */
out = ((q31_t) in >> 1u) + 0x3FFF;
/* Calculation of reciprocal of out */
/* oneByOut contains reciprocal of out which is in 2.14 format
and oneByOut should be upscaled by signBits */
sign_bits = arm_recip_q15((q15_t) out, &oneByOut, armRecipTableQ15);
/* 0.5 * (out) */
out = out >> 1u;
/* prevOut = 0.5 * out + (in * (oneByOut << signBits))) */
prevOut = out + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
/* Third iteration */
sign_bits = arm_recip_q15((q15_t) prevOut, &oneByOut, armRecipTableQ15);
prevOut = prevOut >> 1u;
out = prevOut + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
sign_bits = arm_recip_q15((q15_t) out, &oneByOut, armRecipTableQ15);
out = out >> 1u;
prevOut = out + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
/* Fifth iteration */
sign_bits = arm_recip_q15((q15_t) prevOut, &oneByOut, armRecipTableQ15);
prevOut = prevOut >> 1u;
out = prevOut + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
sign_bits = arm_recip_q15((q15_t) out, &oneByOut, armRecipTableQ15);
out = out >> 1u;
prevOut = out + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
/* Seventh iteration */
sign_bits = arm_recip_q15((q15_t) prevOut, &oneByOut, armRecipTableQ15);
prevOut = prevOut >> 1u;
out = prevOut + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
sign_bits = arm_recip_q15((q15_t) out, &oneByOut, armRecipTableQ15);
out = out >> 1u;
prevOut = out + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
sign_bits = arm_recip_q15((q15_t) prevOut, &oneByOut, armRecipTableQ15);
prevOut = prevOut >> 1u;
out = prevOut + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
/* tenth iteration */
sign_bits = arm_recip_q15((q15_t) out, &oneByOut, armRecipTableQ15);
out = out >> 1u;
*pOut = out + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
return (ARM_MATH_SUCCESS);
}
#else
/* Run the below code for Cortex-M0 */
q31_t out, loopVar; /* Temporary variable for output, loop variable */
if(in > 0)
{
/* run for ten iterations */
/* Take initial guess as half of the input and first iteration */
out = ((q31_t) in >> 1u) + 0x3FFF;
/* Calculation of reciprocal of out */
/* oneByOut contains reciprocal of out which is in 2.14 format
and oneByOut should be upscaled by sign bits */
sign_bits = arm_recip_q15((q15_t) out, &oneByOut, armRecipTableQ15);
/* 0.5 * (out) */
out = out >> 1u;
/* prevOut = 0.5 * out + (in * oneByOut) << signbits))) */
prevOut = out + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
/* loop for third iteration to tenth iteration */
for (loopVar = 1; loopVar <= 8; loopVar++)
{
sign_bits = arm_recip_q15((q15_t) prevOut, &oneByOut, armRecipTableQ15);
/* 0.5 * (prevOut) */
prevOut = prevOut >> 1u;
/* prevOut = 0.5 * prevOut+ (in * oneByOut) << signbits))) */
out =
prevOut + (((q15_t) (((q31_t) in * oneByOut) >> 16)) << sign_bits);
/* prevOut = out */
prevOut = out;
}
/* output is moved to pOut pointer */
*pOut = prevOut;
return (ARM_MATH_SUCCESS);
}
#endif /* #ifndef ARM_MATH_CM0 */
else
{
*pOut = 0;
return (ARM_MATH_ARGUMENT_ERROR);
}
}
/**
* @} end of SQRT group
*/