s_approxRecipSqrt32_1.c File Reference

#include <stdint.h>
#include "platform.h"

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Functions
uint32_t	softfloat_approxRecipSqrt32_1 (unsigned int oddExpA, uint32_t a)

Variables
const uint16_t	softfloat_approxRecipSqrt_1k0s []
const uint16_t	softfloat_approxRecipSqrt_1k1s []

Function Documentation

softfloat_approxRecipSqrt32_1()

uint32_t softfloat_approxRecipSqrt32_1	(	unsigned int	oddExpA,
		uint32_t	a )

Definition at line 45 of file s_approxRecipSqrt32_1.c.

{
    int index;
    uint16_t eps, r0;
    uint_fast32_t ESqrR0;
    uint32_t sigma0;
    uint_fast32_t r;
    uint32_t sqrSigma0;
 
    index = (a>>27 & 0xE) + oddExpA;
    eps = (uint16_t) (a>>12);
    r0 = softfloat_approxRecipSqrt_1k0s[index]
             - ((softfloat_approxRecipSqrt_1k1s[index] * (uint_fast32_t) eps)
                    >>20);
    ESqrR0 = (uint_fast32_t) r0 * r0;
    if ( ! oddExpA ) ESqrR0 <<= 1;
    sigma0 = ~(uint_fast32_t) (((uint32_t) ESqrR0 * (uint_fast64_t) a)>>23);
    r = ((uint_fast32_t) r0<<16) + ((r0 * (uint_fast64_t) sigma0)>>25);
    sqrSigma0 = ((uint_fast64_t) sigma0 * sigma0)>>32;
    r += ((uint32_t) ((r>>1) + (r>>3) - ((uint_fast32_t) r0<<14))
              * (uint_fast64_t) sqrSigma0)
             >>48;
    if ( ! (r & 0x80000000) ) r = 0x80000000;
    return r;
 
}

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Variable Documentation

softfloat_approxRecipSqrt_1k0s

const uint16_t softfloat_approxRecipSqrt_1k0s[]

extern

Definition at line 41 of file s_approxRecipSqrt_1Ks.c.

                                                    {
    0xB4C9, 0xFFAB, 0xAA7D, 0xF11C, 0xA1C5, 0xE4C7, 0x9A43, 0xDA29,
    0x93B5, 0xD0E5, 0x8DED, 0xC8B7, 0x88C6, 0xC16D, 0x8424, 0xBAE1
};

softfloat_approxRecipSqrt_1k1s

const uint16_t softfloat_approxRecipSqrt_1k1s[]

extern

Definition at line 45 of file s_approxRecipSqrt_1Ks.c.

                                                    {
    0xA5A5, 0xEA42, 0x8C21, 0xC62D, 0x788F, 0xAA7F, 0x6928, 0x94B6,
    0x5CC7, 0x8335, 0x52A6, 0x74E2, 0x4A3E, 0x68FE, 0x432B, 0x5EFD
};