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 COMPILER_RT_ABI fp_t __floatsisf(int a)22__floatsisf(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, rounding if it is a right-shift 42 if (exponent <= significandBits) { 43 const int shift = significandBits - exponent; 44 result = (rep_t)a << shift ^ implicitBit; 45 } else { 46 const int shift = exponent - significandBits; 47 result = (rep_t)a >> shift ^ implicitBit; 48 rep_t round = (rep_t)a << (typeWidth - shift); 49 if (round > signBit) result++; 50 if (round == signBit) result += result & 1; 51 } 52 53 // Insert the exponent 54 result += (rep_t)(exponent + exponentBias) << significandBits; 55 // Insert the sign bit and return 56 return fromRep(result | sign); 57 } 58 59 #if defined(__ARM_EABI__) 60 #if defined(COMPILER_RT_ARMHF_TARGET) __aeabi_i2f(int a)61AEABI_RTABI fp_t __aeabi_i2f(int a) { 62 return __floatsisf(a); 63 } 64 #else 65 AEABI_RTABI fp_t __aeabi_i2f(int a) COMPILER_RT_ALIAS(__floatsisf); 66 #endif 67 #endif 68