1 //===-- floatundidf.c - Implement __floatundidf ---------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements __floatundidf for the compiler_rt library. 10 // 11 //===----------------------------------------------------------------------===// 12 13 // Returns: convert a to a double, rounding toward even. 14 15 // Assumption: double is a IEEE 64 bit floating point type 16 // du_int is a 64 bit integral type 17 18 // seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm 19 // mmmm 20 21 #include "int_lib.h" 22 23 #ifndef __SOFTFP__ 24 // Support for systems that have hardware floating-point; we'll set the inexact 25 // flag as a side-effect of this computation. 26 27 COMPILER_RT_ABI double __floatundidf(du_int a) { 28 static const double twop52 = 4503599627370496.0; // 0x1.0p52 29 static const double twop84 = 19342813113834066795298816.0; // 0x1.0p84 30 static const double twop84_plus_twop52 = 31 19342813118337666422669312.0; // 0x1.00000001p84 32 33 union { 34 uint64_t x; 35 double d; 36 } high = {.d = twop84}; 37 union { 38 uint64_t x; 39 double d; 40 } low = {.d = twop52}; 41 42 high.x |= a >> 32; 43 low.x |= a & UINT64_C(0x00000000ffffffff); 44 45 const double result = (high.d - twop84_plus_twop52) + low.d; 46 return result; 47 } 48 49 #else 50 // Support for systems that don't have hardware floating-point; there are no 51 // flags to set, and we don't want to code-gen to an unknown soft-float 52 // implementation. 53 54 #define SRC_U64 55 #define DST_DOUBLE 56 #include "int_to_fp_impl.inc" 57 58 COMPILER_RT_ABI double __floatundidf(du_int a) { return __floatXiYf__(a); } 59 #endif 60 61 #if defined(__ARM_EABI__) 62 #if defined(COMPILER_RT_ARMHF_TARGET) 63 AEABI_RTABI double __aeabi_ul2d(du_int a) { return __floatundidf(a); } 64 #else 65 COMPILER_RT_ALIAS(__floatundidf, __aeabi_ul2d) 66 #endif 67 #endif 68 69 #if defined(__MINGW32__) && defined(__arm__) 70 COMPILER_RT_ALIAS(__floatundidf, __u64tod) 71 #endif 72