| 1 | //===-- floatundidf.c - Implement __floatundidf ---------------------------===// |
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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 __floatundidf 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 | // Returns: convert a to a double, rounding toward even. |
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| 14 | |
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| 15 | // Assumption: double is a IEEE 64 bit floating point type |
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| 16 | // du_int is a 64 bit integral type |
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| 17 | |
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| 18 | // seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm |
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| 19 | // mmmm |
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| 20 | |
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| 21 | #include "int_lib.h" |
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| 22 | |
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| 23 | #ifndef __SOFTFP__ |
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| 24 | // Support for systems that have hardware floating-point; we'll set the inexact |
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| 25 | // flag as a side-effect of this computation. |
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| 26 | |
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| 27 | COMPILER_RT_ABI double __floatundidf(du_int a) { |
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| 28 | static const double twop52 = 4503599627370496.0; // 0x1.0p52 |
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| 29 | static const double twop84 = 19342813113834066795298816.0; // 0x1.0p84 |
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| 30 | static const double twop84_plus_twop52 = |
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| 31 | 19342813118337666422669312.0; // 0x1.00000001p84 |
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| 32 | |
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| 33 | union { |
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| 34 | uint64_t x; |
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| 35 | double d; |
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| 36 | } high = {.d = twop84}; |
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| 37 | union { |
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| 38 | uint64_t x; |
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| 39 | double d; |
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| 40 | } low = {.d = twop52}; |
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| 41 | |
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| 42 | high.x |= a >> 32; |
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| 43 | low.x |= a & UINT64_C(0x00000000ffffffff); |
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| 44 | |
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| 45 | const double result = (high.d - twop84_plus_twop52) + low.d; |
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| 46 | return result; |
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| 47 | } |
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| 48 | |
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| 49 | #else |
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| 50 | // Support for systems that don't have hardware floating-point; there are no |
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| 51 | // flags to set, and we don't want to code-gen to an unknown soft-float |
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| 52 | // implementation. |
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| 53 | |
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| 54 | #define SRC_U64 |
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| 55 | #define DST_DOUBLE |
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| 56 | #include "int_to_fp_impl.inc" |
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| 57 | |
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| 58 | COMPILER_RT_ABI double __floatundidf(du_int a) { return __floatXiYf__(a); } |
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| 59 | #endif |
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| 60 | |
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| 61 | #if defined(__ARM_EABI__) |
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| 62 | #if defined(COMPILER_RT_ARMHF_TARGET) |
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| 63 | AEABI_RTABI double __aeabi_ul2d(du_int a) { return __floatundidf(a); } |
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| 64 | #else |
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| 65 | COMPILER_RT_ALIAS(__floatundidf, __aeabi_ul2d) |
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| 66 | #endif |
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| 67 | #endif |
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| 68 | |
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| 69 | #if defined(__MINGW32__) && defined(__arm__) |
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| 70 | COMPILER_RT_ALIAS(__floatundidf, __u64tod) |
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| 71 | #endif |
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| 72 | |
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