llvm-project

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//===-- fixxfti.c - Implement __fixxfti -----------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements __fixxfti for the compiler_rt library.
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//
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//===----------------------------------------------------------------------===//
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#include "int_lib.h"
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#ifdef CRT_HAS_128BIT
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// Returns: convert a to a signed long long, rounding toward zero.
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// Assumption: long double is an intel 80 bit floating point type padded with 6
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// bytes ti_int is a 128 bit integral type value in long double is representable
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// in ti_int
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// gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee
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// eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm
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// mmmm mmmm mmmm
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COMPILER_RT_ABI ti_int __fixxfti(xf_float a) {
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  const ti_int ti_max = (ti_int)((~(tu_int)0) / 2);
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  const ti_int ti_min = -ti_max - 1;
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  xf_bits fb;
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  fb.f = a;
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  int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
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  if (e < 0)
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    return 0;
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  ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
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  ti_int r = fb.u.low.all;
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  if ((unsigned)e >= sizeof(ti_int) * CHAR_BIT)
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    return a > 0 ? ti_max : ti_min;
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  if (e > 63)
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    r <<= (e - 63);
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  else
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    r >>= (63 - e);
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  return (r ^ s) - s;
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}
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#endif // CRT_HAS_128BIT
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