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author | Stephen Canon <scanon@apple.com> | 2010-07-03 00:56:03 +0000 |
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committer | Stephen Canon <scanon@apple.com> | 2010-07-03 00:56:03 +0000 |
commit | b6d4e2e3a87eb3c9a6dec0ad21d4c1dec545c137 (patch) | |
tree | c85023f7022622149168a816845e2be4f46d696d /lib/floatunsisf.c | |
parent | 455c2633311fe29b036a53eb466f6d65af97de4f (diff) | |
download | compiler-rt-b6d4e2e3a87eb3c9a6dec0ad21d4c1dec545c137.tar.gz compiler-rt-b6d4e2e3a87eb3c9a6dec0ad21d4c1dec545c137.tar.bz2 compiler-rt-b6d4e2e3a87eb3c9a6dec0ad21d4c1dec545c137.tar.xz |
Renamed unsigned->float routines to match GCC convention
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@107554 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/floatunsisf.c')
-rw-r--r-- | lib/floatunsisf.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/floatunsisf.c b/lib/floatunsisf.c new file mode 100644 index 00000000..31c06443 --- /dev/null +++ b/lib/floatunsisf.c @@ -0,0 +1,45 @@ +//===-- 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); +} |