xref: /freebsd-src/contrib/llvm-project/compiler-rt/lib/builtins/floatunsisf.c (revision 1fd87a682ad7442327078e1eeb63edc4258f9815)
10b57cec5SDimitry Andric //===-- lib/floatunsisf.c - uint -> single-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 single-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 SINGLE_PRECISION
160b57cec5SDimitry Andric #include "fp_lib.h"
170b57cec5SDimitry Andric 
180b57cec5SDimitry Andric #include "int_lib.h"
190b57cec5SDimitry Andric 
__floatunsisf(su_int a)20*1fd87a68SDimitry Andric COMPILER_RT_ABI fp_t __floatunsisf(su_int a) {
210b57cec5SDimitry Andric 
220b57cec5SDimitry Andric   const int aWidth = sizeof a * CHAR_BIT;
230b57cec5SDimitry Andric 
240b57cec5SDimitry Andric   // Handle zero as a special case to protect clz
250b57cec5SDimitry Andric   if (a == 0)
260b57cec5SDimitry Andric     return fromRep(0);
270b57cec5SDimitry Andric 
280b57cec5SDimitry Andric   // Exponent of (fp_t)a is the width of abs(a).
29*1fd87a68SDimitry Andric   const int exponent = (aWidth - 1) - clzsi(a);
300b57cec5SDimitry Andric   rep_t result;
310b57cec5SDimitry Andric 
320b57cec5SDimitry Andric   // Shift a into the significand field, rounding if it is a right-shift
330b57cec5SDimitry Andric   if (exponent <= significandBits) {
340b57cec5SDimitry Andric     const int shift = significandBits - exponent;
350b57cec5SDimitry Andric     result = (rep_t)a << shift ^ implicitBit;
360b57cec5SDimitry Andric   } else {
370b57cec5SDimitry Andric     const int shift = exponent - significandBits;
380b57cec5SDimitry Andric     result = (rep_t)a >> shift ^ implicitBit;
390b57cec5SDimitry Andric     rep_t round = (rep_t)a << (typeWidth - shift);
400b57cec5SDimitry Andric     if (round > signBit)
410b57cec5SDimitry Andric       result++;
420b57cec5SDimitry Andric     if (round == signBit)
430b57cec5SDimitry Andric       result += result & 1;
440b57cec5SDimitry Andric   }
450b57cec5SDimitry Andric 
460b57cec5SDimitry Andric   // Insert the exponent
470b57cec5SDimitry Andric   result += (rep_t)(exponent + exponentBias) << significandBits;
480b57cec5SDimitry Andric   return fromRep(result);
490b57cec5SDimitry Andric }
500b57cec5SDimitry Andric 
510b57cec5SDimitry Andric #if defined(__ARM_EABI__)
520b57cec5SDimitry Andric #if defined(COMPILER_RT_ARMHF_TARGET)
__aeabi_ui2f(unsigned int a)530b57cec5SDimitry Andric AEABI_RTABI fp_t __aeabi_ui2f(unsigned int a) { return __floatunsisf(a); }
540b57cec5SDimitry Andric #else
550b57cec5SDimitry Andric COMPILER_RT_ALIAS(__floatunsisf, __aeabi_ui2f)
560b57cec5SDimitry Andric #endif
570b57cec5SDimitry Andric #endif
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