1 //===-- lib/floatsisf.c - integer -> single-precision conversion --*- C -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements integer to single-precision conversion for the 10 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 11 // mode. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #define SINGLE_PRECISION 16 #include "fp_lib.h" 17 18 #include "int_lib.h" 19 20 COMPILER_RT_ABI fp_t __floatsisf(si_int a) { 21 22 const int aWidth = sizeof a * CHAR_BIT; 23 24 // Handle zero as a special case to protect clz 25 if (a == 0) 26 return fromRep(0); 27 28 // All other cases begin by extracting the sign and absolute value of a 29 rep_t sign = 0; 30 su_int aAbs = (su_int)a; 31 if (a < 0) { 32 sign = signBit; 33 aAbs = -aAbs; 34 } 35 36 // Exponent of (fp_t)a is the width of abs(a). 37 const int exponent = (aWidth - 1) - clzsi(aAbs); 38 rep_t result; 39 40 // Shift a into the significand field, rounding if it is a right-shift 41 if (exponent <= significandBits) { 42 const int shift = significandBits - exponent; 43 result = (rep_t)aAbs << shift ^ implicitBit; 44 } else { 45 const int shift = exponent - significandBits; 46 result = (rep_t)aAbs >> shift ^ implicitBit; 47 rep_t round = (rep_t)aAbs << (typeWidth - shift); 48 if (round > signBit) 49 result++; 50 if (round == signBit) 51 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 60 #if defined(__ARM_EABI__) 61 #if defined(COMPILER_RT_ARMHF_TARGET) 62 AEABI_RTABI fp_t __aeabi_i2f(int a) { return __floatsisf(a); } 63 #else 64 COMPILER_RT_ALIAS(__floatsisf, __aeabi_i2f) 65 #endif 66 #endif 67