1 //===-- lib/floatunsisf.c - uint -> single-precision conversion ---*- C -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements unsigned integer to single-precision conversion for the 11 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 12 // mode. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #define SINGLE_PRECISION 17 #include "fp_lib.h" 18 19 #include "int_lib.h" 20 ARM_EABI_FNALIAS(ui2f,floatunsisf)21ARM_EABI_FNALIAS(ui2f, floatunsisf) 22 23 COMPILER_RT_ABI fp_t 24 __floatunsisf(unsigned int a) { 25 26 const int aWidth = sizeof a * CHAR_BIT; 27 28 // Handle zero as a special case to protect clz 29 if (a == 0) return fromRep(0); 30 31 // Exponent of (fp_t)a is the width of abs(a). 32 const int exponent = (aWidth - 1) - __builtin_clz(a); 33 rep_t result; 34 35 // Shift a into the significand field, rounding if it is a right-shift 36 if (exponent <= significandBits) { 37 const int shift = significandBits - exponent; 38 result = (rep_t)a << shift ^ implicitBit; 39 } else { 40 const int shift = exponent - significandBits; 41 result = (rep_t)a >> shift ^ implicitBit; 42 rep_t round = (rep_t)a << (typeWidth - shift); 43 if (round > signBit) result++; 44 if (round == signBit) result += result & 1; 45 } 46 47 // Insert the exponent 48 result += (rep_t)(exponent + exponentBias) << significandBits; 49 return fromRep(result); 50 } 51