46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
//===-- lib/floatunsisf.c - uint -> single-precision conversion ---*- C -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements unsigned integer to single-precision conversion for the
|
|
// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
|
|
// mode.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#define SINGLE_PRECISION
|
|
#include "fp_lib.h"
|
|
|
|
fp_t __floatunsisf(unsigned int a) {
|
|
|
|
const int aWidth = sizeof a * CHAR_BIT;
|
|
|
|
// Handle zero as a special case to protect clz
|
|
if (a == 0) return fromRep(0);
|
|
|
|
// Exponent of (fp_t)a is the width of abs(a).
|
|
const int exponent = (aWidth - 1) - __builtin_clz(a);
|
|
rep_t result;
|
|
|
|
// Shift a into the significand field, rounding if it is a right-shift
|
|
if (exponent <= significandBits) {
|
|
const int shift = significandBits - exponent;
|
|
result = (rep_t)a << shift ^ implicitBit;
|
|
} else {
|
|
const int shift = exponent - significandBits;
|
|
result = (rep_t)a >> shift ^ implicitBit;
|
|
rep_t round = (rep_t)a << (typeWidth - shift);
|
|
if (round > signBit) result++;
|
|
if (round == signBit) result += result & 1;
|
|
}
|
|
|
|
// Insert the exponent
|
|
result += (rep_t)(exponent + exponentBias) << significandBits;
|
|
return fromRep(result);
|
|
}
|