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Diffstat (limited to 'lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecip32_1.c')
-rw-r--r-- | lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecip32_1.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecip32_1.c b/lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecip32_1.c new file mode 100644 index 0000000..14ddd95 --- /dev/null +++ b/lib/libutils/isoc/arch/arm/softfloat/source/s_approxRecip32_1.c @@ -0,0 +1,71 @@ + +/*============================================================================ + +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_approxRecip32_1 + +uint32_t softfloat_approxRecip32_1( uint32_t a ) +{ + int index; + uint16_t eps; + static const uint16_t k0s[] = { + 0xFFC4, 0xF0BE, 0xE363, 0xD76F, 0xCCAD, 0xC2F0, 0xBA16, 0xB201, + 0xAA97, 0xA3C6, 0x9D7A, 0x97A6, 0x923C, 0x8D32, 0x887E, 0x8417 + }; + static const uint16_t k1s[] = { + 0xF0F1, 0xD62C, 0xBFA1, 0xAC77, 0x9C0A, 0x8DDB, 0x8185, 0x76BA, + 0x6D3B, 0x64D4, 0x5D5C, 0x56B1, 0x50B6, 0x4B55, 0x4679, 0x4211 + }; + uint16_t r0; + uint32_t delta0; + uint_fast32_t r; + uint32_t sqrDelta0; + + index = a>>27 & 0xF; + eps = (uint16_t) (a>>11); + r0 = k0s[index] - ((k1s[index] * (uint_fast32_t) eps)>>20); + delta0 = ~(uint_fast32_t) ((r0 * (uint_fast64_t) a)>>7); + r = ((uint_fast32_t) r0<<16) + ((r0 * (uint_fast64_t) delta0)>>24); + sqrDelta0 = ((uint_fast64_t) delta0 * delta0)>>32; + r += ((uint32_t) r * (uint_fast64_t) sqrDelta0)>>48; + return r; + +} + +#endif + |