46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
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/* ===-- fixdfti.c - Implement __fixdfti -----------------------------------===
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*
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* The LLVM Compiler Infrastructure
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*
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* This file is dual licensed under the MIT and the University of Illinois Open
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* Source Licenses. See LICENSE.TXT for details.
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*
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* ===----------------------------------------------------------------------===
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*
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* This file implements __fixdfti for the compiler_rt library.
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*
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* ===----------------------------------------------------------------------===
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*/
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#include "int_lib.h"
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#if __x86_64
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/* Returns: convert a to a signed long long, rounding toward zero. */
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/* Assumption: double is a IEEE 64 bit floating point type
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* su_int is a 32 bit integral type
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* value in double is representable in ti_int (no range checking performed)
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*/
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/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
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ti_int
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__fixdfti(double a)
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{
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double_bits fb;
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fb.f = a;
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int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
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if (e < 0)
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return 0;
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ti_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31;
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ti_int r = 0x0010000000000000uLL | (0x000FFFFFFFFFFFFFuLL & fb.u.all);
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if (e > 52)
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r <<= (e - 52);
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else
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r >>= (52 - e);
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return (r ^ s) - s;
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}
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#endif
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