xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/floatunsitf.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
10b57cec5SDimitry Andric //===-- lib/floatunsitf.c - uint -> quad-precision conversion -----*- C -*-===//
20b57cec5SDimitry Andric //
30b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
40b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
50b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
60b57cec5SDimitry Andric //
70b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
80b57cec5SDimitry Andric //
90b57cec5SDimitry Andric // This file implements unsigned integer to quad-precision conversion for the
100b57cec5SDimitry Andric // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
110b57cec5SDimitry Andric // mode.
120b57cec5SDimitry Andric //
130b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
140b57cec5SDimitry Andric 
150b57cec5SDimitry Andric #define QUAD_PRECISION
160b57cec5SDimitry Andric #include "fp_lib.h"
170b57cec5SDimitry Andric 
18*06c3fb27SDimitry Andric #if defined(CRT_HAS_TF_MODE)
__floatunsitf(su_int a)191fd87a68SDimitry Andric COMPILER_RT_ABI fp_t __floatunsitf(su_int a) {
200b57cec5SDimitry Andric 
210b57cec5SDimitry Andric   const int aWidth = sizeof a * CHAR_BIT;
220b57cec5SDimitry Andric 
230b57cec5SDimitry Andric   // Handle zero as a special case to protect clz
240b57cec5SDimitry Andric   if (a == 0)
250b57cec5SDimitry Andric     return fromRep(0);
260b57cec5SDimitry Andric 
270b57cec5SDimitry Andric   // Exponent of (fp_t)a is the width of abs(a).
281fd87a68SDimitry Andric   const int exponent = (aWidth - 1) - clzsi(a);
290b57cec5SDimitry Andric   rep_t result;
300b57cec5SDimitry Andric 
310b57cec5SDimitry Andric   // Shift a into the significand field and clear the implicit bit.
320b57cec5SDimitry Andric   const int shift = significandBits - exponent;
330b57cec5SDimitry Andric   result = (rep_t)a << shift ^ implicitBit;
340b57cec5SDimitry Andric 
350b57cec5SDimitry Andric   // Insert the exponent
360b57cec5SDimitry Andric   result += (rep_t)(exponent + exponentBias) << significandBits;
370b57cec5SDimitry Andric   return fromRep(result);
380b57cec5SDimitry Andric }
390b57cec5SDimitry Andric 
400b57cec5SDimitry Andric #endif
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