mirror of
https://github.com/ilyakooo0/urbit.git
synced 2024-12-24 23:44:56 +03:00
69 lines
2.7 KiB
C
69 lines
2.7 KiB
C
|
|
/*============================================================================
|
|
|
|
This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
|
|
Package, Release 3, by John R. Hauser.
|
|
|
|
Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
|
|
California (Regents). All Rights Reserved. Redistribution and use in source
|
|
and binary forms, with or without modification, are permitted provided that
|
|
the following conditions are met:
|
|
|
|
Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions, and the following two paragraphs of disclaimer.
|
|
Redistributions in binary form must reproduce the above copyright notice,
|
|
this list of conditions, and the following two paragraphs of disclaimer in the
|
|
documentation and/or other materials provided with the distribution. Neither
|
|
the name of the Regents nor the names of its contributors may be used to
|
|
endorse or promote products derived from this software without specific prior
|
|
written permission.
|
|
|
|
IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
|
|
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
|
|
OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
|
|
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
|
|
HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
|
|
MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
|
|
|
|
=============================================================================*/
|
|
|
|
#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
|
|
|