| //===-- lib/floatsitf.c - integer -> quad-precision conversion ----*- C -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements integer to quad-precision conversion for the |
| // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even |
| // mode. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define QUAD_PRECISION |
| #include "fp_lib.h" |
| |
| #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) |
| COMPILER_RT_ABI fp_t __floatsitf(int a) { |
| |
| const int aWidth = sizeof a * CHAR_BIT; |
| |
| // Handle zero as a special case to protect clz |
| if (a == 0) |
| return fromRep(0); |
| |
| // All other cases begin by extracting the sign and absolute value of a |
| rep_t sign = 0; |
| unsigned aAbs = (unsigned)a; |
| if (a < 0) { |
| sign = signBit; |
| aAbs = ~(unsigned)a + 1U; |
| } |
| |
| // Exponent of (fp_t)a is the width of abs(a). |
| const int exponent = (aWidth - 1) - __builtin_clz(aAbs); |
| rep_t result; |
| |
| // Shift a into the significand field and clear the implicit bit. |
| const int shift = significandBits - exponent; |
| result = (rep_t)aAbs << shift ^ implicitBit; |
| |
| // Insert the exponent |
| result += (rep_t)(exponent + exponentBias) << significandBits; |
| // Insert the sign bit and return |
| return fromRep(result | sign); |
| } |
| |
| #endif |
