67 lines · c
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-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements integer to single-precision conversion for the10// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even11// mode.12//13//===----------------------------------------------------------------------===//14 15#define SINGLE_PRECISION16#include "fp_lib.h"17 18#include "int_lib.h"19 20COMPILER_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 clz25 if (a == 0)26 return fromRep(0);27 28 // All other cases begin by extracting the sign and absolute value of a29 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-shift41 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 exponent55 result += (rep_t)(exponent + exponentBias) << significandBits;56 // Insert the sign bit and return57 return fromRep(result | sign);58}59 60#if defined(__ARM_EABI__)61#if defined(COMPILER_RT_ARMHF_TARGET)62AEABI_RTABI fp_t __aeabi_i2f(int a) { return __floatsisf(a); }63#else64COMPILER_RT_ALIAS(__floatsisf, __aeabi_i2f)65#endif66#endif67