1*0a6a1f1dSLionel Sambuc //===-- lib/floatunsidf.c - uint -> double-precision conversion ---*- C -*-===// 2*0a6a1f1dSLionel Sambuc // 3*0a6a1f1dSLionel Sambuc // The LLVM Compiler Infrastructure 4*0a6a1f1dSLionel Sambuc // 5*0a6a1f1dSLionel Sambuc // This file is dual licensed under the MIT and the University of Illinois Open 6*0a6a1f1dSLionel Sambuc // Source Licenses. See LICENSE.TXT for details. 7*0a6a1f1dSLionel Sambuc // 8*0a6a1f1dSLionel Sambuc //===----------------------------------------------------------------------===// 9*0a6a1f1dSLionel Sambuc // 10*0a6a1f1dSLionel Sambuc // This file implements unsigned integer to double-precision conversion for the 11*0a6a1f1dSLionel Sambuc // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 12*0a6a1f1dSLionel Sambuc // mode. 13*0a6a1f1dSLionel Sambuc // 14*0a6a1f1dSLionel Sambuc //===----------------------------------------------------------------------===// 15*0a6a1f1dSLionel Sambuc 16*0a6a1f1dSLionel Sambuc #define DOUBLE_PRECISION 17*0a6a1f1dSLionel Sambuc #include "fp_lib.h" 18*0a6a1f1dSLionel Sambuc 19*0a6a1f1dSLionel Sambuc #include "int_lib.h" 20*0a6a1f1dSLionel Sambuc ARM_EABI_FNALIAS(ui2d,floatunsidf)21*0a6a1f1dSLionel SambucARM_EABI_FNALIAS(ui2d, floatunsidf) 22*0a6a1f1dSLionel Sambuc 23*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI fp_t 24*0a6a1f1dSLionel Sambuc __floatunsidf(unsigned int a) { 25*0a6a1f1dSLionel Sambuc 26*0a6a1f1dSLionel Sambuc const int aWidth = sizeof a * CHAR_BIT; 27*0a6a1f1dSLionel Sambuc 28*0a6a1f1dSLionel Sambuc // Handle zero as a special case to protect clz 29*0a6a1f1dSLionel Sambuc if (a == 0) return fromRep(0); 30*0a6a1f1dSLionel Sambuc 31*0a6a1f1dSLionel Sambuc // Exponent of (fp_t)a is the width of abs(a). 32*0a6a1f1dSLionel Sambuc const int exponent = (aWidth - 1) - __builtin_clz(a); 33*0a6a1f1dSLionel Sambuc rep_t result; 34*0a6a1f1dSLionel Sambuc 35*0a6a1f1dSLionel Sambuc // Shift a into the significand field and clear the implicit bit. 36*0a6a1f1dSLionel Sambuc const int shift = significandBits - exponent; 37*0a6a1f1dSLionel Sambuc result = (rep_t)a << shift ^ implicitBit; 38*0a6a1f1dSLionel Sambuc 39*0a6a1f1dSLionel Sambuc // Insert the exponent 40*0a6a1f1dSLionel Sambuc result += (rep_t)(exponent + exponentBias) << significandBits; 41*0a6a1f1dSLionel Sambuc return fromRep(result); 42*0a6a1f1dSLionel Sambuc } 43