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Diffstat (limited to 'contrib/compiler-rt/lib/builtins/floatsitf.c')
-rw-r--r-- | contrib/compiler-rt/lib/builtins/floatsitf.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/builtins/floatsitf.c b/contrib/compiler-rt/lib/builtins/floatsitf.c new file mode 100644 index 000000000000..85346933f81e --- /dev/null +++ b/contrib/compiler-rt/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 |