72 lines · c
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-exception6//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 type16// du_int is a 64 bit integral type17 18// seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm19// mmmm20 21#include "int_lib.h"22 23#ifndef __SOFTFP__24// Support for systems that have hardware floating-point; we'll set the inexact25// flag as a side-effect of this computation.26 27COMPILER_RT_ABI double __floatundidf(du_int a) {28 static const double twop52 = 4503599627370496.0; // 0x1.0p5229 static const double twop84 = 19342813113834066795298816.0; // 0x1.0p8430 static const double twop84_plus_twop52 =31 19342813118337666422669312.0; // 0x1.00000001p8432 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#else50// Support for systems that don't have hardware floating-point; there are no51// flags to set, and we don't want to code-gen to an unknown soft-float52// implementation.53 54#define SRC_U6455#define DST_DOUBLE56#include "int_to_fp_impl.inc"57 58COMPILER_RT_ABI double __floatundidf(du_int a) { return __floatXiYf__(a); }59#endif60 61#if defined(__ARM_EABI__)62#if defined(COMPILER_RT_ARMHF_TARGET)63AEABI_RTABI double __aeabi_ul2d(du_int a) { return __floatundidf(a); }64#else65COMPILER_RT_ALIAS(__floatundidf, __aeabi_ul2d)66#endif67#endif68 69#if defined(__MINGW32__) && defined(__arm__)70COMPILER_RT_ALIAS(__floatundidf, __u64tod)71#endif72