diff options
author | Joerg Sonnenberger <joerg@bec.de> | 2014-09-16 20:34:41 +0000 |
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committer | Joerg Sonnenberger <joerg@bec.de> | 2014-09-16 20:34:41 +0000 |
commit | 086f46a9b87b17d36de8cc7e7f4b5a7469161cca (patch) | |
tree | 056ad3a0cb3ff7b3670b81ef8270426e9a9e33c8 /lib/builtins/floatsitf.c | |
parent | 48d5c81378502ac2f26565f76caec9601e702e6a (diff) |
Implement floatsitf, floatunstfsi, which perform
(signed/unsigned)integer to quad-precision conversion.
Submitted by GuanHong Liu.
Differential Revision: http://reviews.llvm.org/D2805
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@217901 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/builtins/floatsitf.c')
-rw-r--r-- | lib/builtins/floatsitf.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/lib/builtins/floatsitf.c b/lib/builtins/floatsitf.c new file mode 100644 index 000000000..85346933f --- /dev/null +++ b/lib/builtins/floatsitf.c @@ -0,0 +1,52 @@ +//===-- 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 += 0x80000000; + } + + // 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 and clear the implicit bit. Extra + // cast to unsigned int is necessary to get the correct behavior for + // the input INT_MIN. + 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 |