91bd698eaf
80bit Intel/PPC long double is excluded due to lacking support for the abstraction. Consistently provide saturation logic. Extend to long double on 128bit IEEE extended platforms. Initial patch with test cases from GuanHong Liu. Reviewed by Steve Canon. Differential Revision: http://reviews.llvm.org/D2804 llvm-svn: 231965
52 lines
1.5 KiB
C
52 lines
1.5 KiB
C
/* ===-- fixxfti.c - Implement __fixxfti -----------------------------------===
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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 __fixxfti 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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#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 bytes
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* ti_int is a 128 bit integral type
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* value in long double is representable in ti_int
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*/
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/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
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* 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
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*/
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COMPILER_RT_ABI ti_int
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__fixxfti(long double a)
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{
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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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long_double_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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