1 //===-- lib/floatunsidf.c - uint -> double-precision conversion ---*- C -*-===// 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 unsigned integer to double-precision conversion for the 10 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 11 // mode. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #define DOUBLE_PRECISION 16 #include "fp_lib.h" 17 18 #include "int_lib.h" 19 20 COMPILER_RT_ABI fp_t __floatunsidf(su_int a) { 21 22 const int aWidth = sizeof a * CHAR_BIT; 23 24 // Handle zero as a special case to protect clz 25 if (a == 0) 26 return fromRep(0); 27 28 // Exponent of (fp_t)a is the width of abs(a). 29 const int exponent = (aWidth - 1) - clzsi(a); 30 rep_t result; 31 32 // Shift a into the significand field and clear the implicit bit. 33 const int shift = significandBits - exponent; 34 result = (rep_t)a << shift ^ implicitBit; 35 36 // Insert the exponent 37 result += (rep_t)(exponent + exponentBias) << significandBits; 38 return fromRep(result); 39 } 40 41 #if defined(__ARM_EABI__) 42 #if defined(COMPILER_RT_ARMHF_TARGET) 43 AEABI_RTABI fp_t __aeabi_ui2d(su_int a) { return __floatunsidf(a); } 44 #else 45 COMPILER_RT_ALIAS(__floatunsidf, __aeabi_ui2d) 46 #endif 47 #endif 48