1 //===-- lib/floatsidf.c - integer -> double-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 double-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 DOUBLE_PRECISION 17 #include "fp_lib.h" 18 19 #include "int_lib.h" 20 21 COMPILER_RT_ABI fp_t __floatsidf(int a)22__floatsidf(int a) { 23 24 const int aWidth = sizeof a * CHAR_BIT; 25 26 // Handle zero as a special case to protect clz 27 if (a == 0) 28 return fromRep(0); 29 30 // All other cases begin by extracting the sign and absolute value of a 31 rep_t sign = 0; 32 if (a < 0) { 33 sign = signBit; 34 a = -a; 35 } 36 37 // Exponent of (fp_t)a is the width of abs(a). 38 const int exponent = (aWidth - 1) - __builtin_clz(a); 39 rep_t result; 40 41 // Shift a into the significand field and clear the implicit bit. Extra 42 // cast to unsigned int is necessary to get the correct behavior for 43 // the input INT_MIN. 44 const int shift = significandBits - exponent; 45 result = (rep_t)(unsigned int)a << shift ^ implicitBit; 46 47 // Insert the exponent 48 result += (rep_t)(exponent + exponentBias) << significandBits; 49 // Insert the sign bit and return 50 return fromRep(result | sign); 51 } 52 53 #if defined(__ARM_EABI__) 54 #if defined(COMPILER_RT_ARMHF_TARGET) __aeabi_i2d(int a)55AEABI_RTABI fp_t __aeabi_i2d(int a) { 56 return __floatsidf(a); 57 } 58 #else 59 AEABI_RTABI fp_t __aeabi_i2d(int a) COMPILER_RT_ALIAS(__floatsidf); 60 #endif 61 #endif 62