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Diffstat (limited to 'contrib/llvm-project/compiler-rt/lib/builtins/floatditf.c')
-rw-r--r-- | contrib/llvm-project/compiler-rt/lib/builtins/floatditf.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/floatditf.c b/contrib/llvm-project/compiler-rt/lib/builtins/floatditf.c new file mode 100644 index 000000000000..c6e326a1923a --- /dev/null +++ b/contrib/llvm-project/compiler-rt/lib/builtins/floatditf.c @@ -0,0 +1,49 @@ +//===-- lib/floatditf.c - integer -> quad-precision conversion ----*- C -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements di_int 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_TF_MODE) +COMPILER_RT_ABI fp_t __floatditf(di_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; + du_int aAbs = (du_int)a; + if (a < 0) { + sign = signBit; + aAbs = ~(du_int)a + 1U; + } + + // Exponent of (fp_t)a is the width of abs(a). + const int exponent = (aWidth - 1) - __builtin_clzll(aAbs); + rep_t result; + + // Shift a into the significand field, rounding if it is a right-shift + 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 |