forked from OSchip/llvm-project
44 lines
1.3 KiB
C
44 lines
1.3 KiB
C
//===-- 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 distributed under the University of Illinois Open Source
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// License. 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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#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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// 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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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.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
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