| 1 | //===-- floatdixf.c - Implement __floatdixf -------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file implements __floatdixf for the compiler_rt library. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |
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| 13 | #if !_ARCH_PPC |
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| 14 | |
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| 15 | #include "int_lib.h" |
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| 16 | |
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| 17 | // Returns: convert a to a long double, rounding toward even. |
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| 18 | |
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| 19 | // Assumption: long double is a IEEE 80 bit floating point type padded to 128 |
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| 20 | // bits di_int is a 64 bit integral type |
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| 21 | |
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| 22 | // gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee |
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| 23 | // eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm |
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| 24 | // mmmm mmmm mmmm |
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| 25 | |
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| 26 | COMPILER_RT_ABI xf_float __floatdixf(di_int a) { |
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| 27 | if (a == 0) |
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| 28 | return 0.0; |
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| 29 | const unsigned N = sizeof(di_int) * CHAR_BIT; |
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| 30 | const di_int s = a >> (N - 1); |
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| 31 | a = (a ^ s) - s; |
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| 32 | int clz = __builtin_clzll(a); |
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| 33 | int e = (N - 1) - clz; // exponent |
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| 34 | xf_bits fb; |
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| 35 | fb.u.high.s.low = ((su_int)s & 0x00008000) | // sign |
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| 36 | (e + 16383); // exponent |
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| 37 | fb.u.low.all = a << clz; // mantissa |
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| 38 | return fb.f; |
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| 39 | } |
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| 40 | |
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| 41 | #endif // !_ARCH_PPC |
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| 42 | |
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