| 1 | //===-- lib/floatunditf.c - uint -> quad-precision conversion -----*- C -*-===// |
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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 du_int to quad-precision conversion for the |
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| 10 | // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even |
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| 11 | // mode. |
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| 12 | // |
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| 13 | //===----------------------------------------------------------------------===// |
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| 14 | |
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| 15 | #define QUAD_PRECISION |
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| 16 | #include "fp_lib.h" |
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| 17 | |
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| 18 | #if defined(CRT_HAS_TF_MODE) |
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| 19 | COMPILER_RT_ABI fp_t __floatunditf(du_int a) { |
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| 20 | |
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| 21 | const int aWidth = sizeof a * CHAR_BIT; |
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| 22 | |
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| 23 | // Handle zero as a special case to protect clz |
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| 24 | if (a == 0) |
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| 25 | return fromRep(x: 0); |
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| 26 | |
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| 27 | // Exponent of (fp_t)a is the width of abs(a). |
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| 28 | const int exponent = (aWidth - 1) - __builtin_clzll(a); |
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| 29 | rep_t result; |
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| 30 | |
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| 31 | // Shift a into the significand field and clear the implicit bit. |
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| 32 | const int shift = significandBits - exponent; |
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| 33 | result = (rep_t)a << shift ^ implicitBit; |
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| 34 | |
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| 35 | // Insert the exponent |
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| 36 | result += (rep_t)(exponent + exponentBias) << significandBits; |
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| 37 | return fromRep(x: result); |
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| 38 | } |
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| 39 | |
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| 40 | #endif |
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| 41 | |
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