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Diffstat (limited to 'lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecipSqrt32_1.c')
-rw-r--r-- | lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecipSqrt32_1.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecipSqrt32_1.c b/lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecipSqrt32_1.c new file mode 100644 index 0000000..a318673 --- /dev/null +++ b/lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecipSqrt32_1.c @@ -0,0 +1,77 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3a, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of +California. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions, and the following disclaimer. + + 2. 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. + + 3. Neither the name of the University 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 REGENTS 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 REGENTS 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 <stdint.h> +#include "platform.h" + +#ifndef softfloat_approxRecipSqrt32_1 + +uint32_t softfloat_approxRecipSqrt32_1( unsigned int oddExpA, uint32_t a ) +{ + int index; + uint16_t eps; + static const uint16_t k0s[] = { + 0xB4C9, 0xFFAB, 0xAA7D, 0xF11C, 0xA1C5, 0xE4C7, 0x9A43, 0xDA29, + 0x93B5, 0xD0E5, 0x8DED, 0xC8B7, 0x88C6, 0xC16D, 0x8424, 0xBAE1 + }; + static const uint16_t k1s[] = { + 0xA5A5, 0xEA42, 0x8C21, 0xC62D, 0x788F, 0xAA7F, 0x6928, 0x94B6, + 0x5CC7, 0x8335, 0x52A6, 0x74E2, 0x4A3E, 0x68FE, 0x432B, 0x5EFD + }; + uint16_t r0; + uint_fast32_t ESqrR0; + uint32_t delta0; + uint_fast32_t r; + uint32_t sqrDelta0; + + index = (a>>27 & 0xE) + oddExpA; + eps = (uint16_t) (a>>12); + r0 = k0s[index] - ((k1s[index] * (uint_fast32_t) eps)>>20); + ESqrR0 = (uint_fast32_t) r0 * r0; + if ( ! oddExpA ) ESqrR0 <<= 1; + delta0 = ~(uint_fast32_t) (((uint32_t) ESqrR0 * (uint_fast64_t) a)>>23); + r = ((uint_fast32_t) r0<<16) + ((r0 * (uint_fast64_t) delta0)>>25); + sqrDelta0 = ((uint_fast64_t) delta0 * delta0)>>32; + r += ((uint32_t) ((r>>1) + (r>>3) - ((uint_fast32_t) r0<<14)) + * (uint_fast64_t) sqrDelta0) + >>48; + if ( ! (r & 0x80000000) ) r = 0x80000000; + return r; + +} + +#endif + |