1 //===-- lib/floatsisf.c - integer -> 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 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 21 ARM_EABI_FNALIAS(i2f, floatsisf) 22 23 fp_t __floatsisf(int a) { 24 25 const int aWidth = sizeof a * CHAR_BIT; 26 27 // Handle zero as a special case to protect clz 28 if (a == 0) 29 return fromRep(0); 30 31 // All other cases begin by extracting the sign and absolute value of a 32 rep_t sign = 0; 33 if (a < 0) { 34 sign = signBit; 35 a = -a; 36 } 37 38 // Exponent of (fp_t)a is the width of abs(a). 39 const int exponent = (aWidth - 1) - __builtin_clz(a); 40 rep_t result; 41 42 // Shift a into the significand field, rounding if it is a right-shift 43 if (exponent <= significandBits) { 44 const int shift = significandBits - exponent; 45 result = (rep_t)a << shift ^ implicitBit; 46 } else { 47 const int shift = exponent - significandBits; 48 result = (rep_t)a >> shift ^ implicitBit; 49 rep_t round = (rep_t)a << (typeWidth - shift); 50 if (round > signBit) result++; 51 if (round == signBit) result += result & 1; 52 } 53 54 // Insert the exponent 55 result += (rep_t)(exponent + exponentBias) << significandBits; 56 // Insert the sign bit and return 57 return fromRep(result | sign); 58 } 59
