65 lines
2.2 KiB
C
65 lines
2.2 KiB
C
/* 128-bit floating point to 32-bit fixed point unsigned integer.
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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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/* unsigned int _q_qtou(const long double *a);
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Convert 'a' to unsigned int by truncation.
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Special cases:
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-0: return 0
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NaN: raise VXCVI, return 0
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SNaN: raise VXSNAN, VXCVI, and return 0
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Negative numbers (other than -0, but including -Inf): raise VXCVI, return 0
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>= 2^32: raise VXCVI, return 0xffffffff
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*/
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unsigned int
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__q_qtou(const unsigned long long a[2])
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{
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int ax;
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unsigned result;
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unsigned long long a0;
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/* Deal with non-special cases. */
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a0 = a[0];
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ax = (a0 >> 48) - 16383;
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if (ax <= 31)
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/* If we had a '>>' operator that behaved properly with respect to
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large shifts, we wouldn't need the '& -(ax >> 31)' term, which
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clears 'result' if ax is negative. */
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return (unsigned)(a0 >> 17 | 0x80000000) >> 31-ax & -(ax >> 31);
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/* 'result' is 1 if a is negative, 0 otherwise. */
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result = a0 >> 63;
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/* Check for -0, otherwise raise VXCVI. */
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if (a0 != 0x8000000000000000ULL || a[1] != 0)
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{
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/* Check for SNaN, if so raise VXSNAN. */
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if ((a0 >> 32 & 0x7fff8000) == 0x7fff0000
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&& (a[1] | a0 & 0x00007fffffffffffULL) != 0)
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set_fpscr_bit(FPSCR_VXSNAN);
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/* Treat all NaNs as large negative numbers. */
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result |= cntlzw(~(a0 >> 32) & 0x7fff0000) >> 5;
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set_fpscr_bit(FPSCR_VXCVI);
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}
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return result-1;
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}
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