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author | Andrew Waterman <andrew@sifive.com> | 2018-07-11 01:16:28 -0700 |
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committer | Andrew Waterman <andrew@sifive.com> | 2018-07-11 01:16:28 -0700 |
commit | 5cd8d2b93fad2011fdf8f49a263d77697af35b32 (patch) | |
tree | f6fb9cb6d3bef2aa5c9903511b92e5a6e99e9519 /softfloat/s_approxRecipSqrt32_1.c | |
parent | 8e69141749065ff957383d2112768f95a33429b6 (diff) | |
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Upgrade to SoftFloat 3e
Diffstat (limited to 'softfloat/s_approxRecipSqrt32_1.c')
-rw-r--r-- | softfloat/s_approxRecipSqrt32_1.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/softfloat/s_approxRecipSqrt32_1.c b/softfloat/s_approxRecipSqrt32_1.c new file mode 100644 index 0000000..28eca64 --- /dev/null +++ b/softfloat/s_approxRecipSqrt32_1.c @@ -0,0 +1,73 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3e, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2015, 2016 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 + +extern const uint16_t softfloat_approxRecipSqrt_1k0s[]; +extern const uint16_t softfloat_approxRecipSqrt_1k1s[]; + +uint32_t softfloat_approxRecipSqrt32_1( unsigned int oddExpA, uint32_t a ) +{ + 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; + +} + +#endif + |