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Diffstat (limited to 'compiler-rt/lib/builtins/fixxfti.c')
-rw-r--r-- | compiler-rt/lib/builtins/fixxfti.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/compiler-rt/lib/builtins/fixxfti.c b/compiler-rt/lib/builtins/fixxfti.c new file mode 100644 index 000000000000..90e03116e7ca --- /dev/null +++ b/compiler-rt/lib/builtins/fixxfti.c @@ -0,0 +1,46 @@ +//===-- fixxfti.c - Implement __fixxfti -----------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements __fixxfti for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#include "int_lib.h" + +#ifdef CRT_HAS_128BIT + +// Returns: convert a to a signed long long, rounding toward zero. + +// Assumption: long double is an intel 80 bit floating point type padded with 6 +// bytes ti_int is a 128 bit integral type value in long double is representable +// in ti_int + +// gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee +// eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm +// mmmm mmmm mmmm + +COMPILER_RT_ABI ti_int __fixxfti(long double a) { + const ti_int ti_max = (ti_int)((~(tu_int)0) / 2); + const ti_int ti_min = -ti_max - 1; + long_double_bits fb; + fb.f = a; + int e = (fb.u.high.s.low & 0x00007FFF) - 16383; + if (e < 0) + return 0; + ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15); + ti_int r = fb.u.low.all; + if ((unsigned)e >= sizeof(ti_int) * CHAR_BIT) + return a > 0 ? ti_max : ti_min; + if (e > 63) + r <<= (e - 63); + else + r >>= (63 - e); + return (r ^ s) - s; +} + +#endif // CRT_HAS_128BIT |