47 lines
1.4 KiB
C
47 lines
1.4 KiB
C
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/* ===-- floatdixf.c - Implement __floatdixf -------------------------------===
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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 __floatdixf for the compiler_rt library.
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*
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* ===----------------------------------------------------------------------===
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*/
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#if !_ARCH_PPC
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#include "int_lib.h"
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/* Returns: convert a to a long double, rounding toward even. */
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/* Assumption: long double is a IEEE 80 bit floating point type padded to 128 bits
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* di_int is a 64 bit integral type
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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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long double
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__floatdixf(di_int a)
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{
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if (a == 0)
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return 0.0;
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const unsigned N = sizeof(di_int) * CHAR_BIT;
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const di_int s = a >> (N-1);
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a = (a ^ s) - s;
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int clz = __builtin_clzll(a);
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int e = (N - 1) - clz ; /* exponent */
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long_double_bits fb;
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fb.u.high.s.low = ((su_int)s & 0x00008000) | /* sign */
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(e + 16383); /* exponent */
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fb.u.low.all = a << clz; /* mantissa */
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return fb.f;
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}
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#endif /* !_ARCH_PPC */
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