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 if (a < 0) { 31 sign = signBit; 32 a = -a; 33 } 34 35 // Exponent of (fp_t)a is the width of abs(a). 36 const int exponent = (aWidth - 1) - clzsi(a); 37 rep_t result; 38 39 // Shift a into the significand field, rounding if it is a right-shift 40 if (exponent <= significandBits) { 41 const int shift = significandBits - exponent; 42 result = (rep_t)a << shift ^ implicitBit; 43 } else { 44 const int shift = exponent - significandBits; 45 result = (rep_t)a >> shift ^ implicitBit; 46 rep_t round = (rep_t)a << (typeWidth - shift); 47 if (round > signBit) 48 result++; 49 if (round == signBit) 50 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) 61 AEABI_RTABI fp_t __aeabi_i2f(int a) { return __floatsisf(a); } 62 #else 63 COMPILER_RT_ALIAS(__floatsisf, __aeabi_i2f) 64 #endif 65 #endif 66