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51 lines
1.6 KiB
C
51 lines
1.6 KiB
C
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/* 32-bit fixed point signed integer to 128-bit floating point.
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Copyright (C) 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <quad_float.h>
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/* long double _q_itoq(int a);
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Convert 'a' to long double.
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*/
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void
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__q_itoq(unsigned int result[4], int a)
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{
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unsigned rx;
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int cs, css;
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/* Note that if a==-2^31, then ua will be 2^31. */
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unsigned int ua = abs(a);
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/* Normalize. */
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cs = cntlzw(ua);
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ua <<= cs+1;
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/* Calculate the exponent, in 4 easy instructions. */
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css = 31-cs;
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rx = 16383+css << 16 & ~css;
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/* Copy the sign bit from 'a'. */
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asm ("rlwimi %0,%1,0,0,0": "=r"(rx) : "r"(a), "0"(rx));
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/* Put it all together. */
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result[2] = result[3] = 0;
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asm ("rlwimi %0,%1,16,16,31": "=r"(result[0]) : "r"(ua), "0"(rx));
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result[1] = ua << 16;
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}
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