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Diffstat (limited to 'lib/builtins/fixdfti.c')
-rw-r--r-- | lib/builtins/fixdfti.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/builtins/fixdfti.c b/lib/builtins/fixdfti.c new file mode 100644 index 000000000000..2c27f4bae3b9 --- /dev/null +++ b/lib/builtins/fixdfti.c @@ -0,0 +1,45 @@ +/* ===-- fixdfti.c - Implement __fixdfti -----------------------------------=== + * + * 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 __fixdfti 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: double is a IEEE 64 bit floating point type + * su_int is a 32 bit integral type + * value in double is representable in ti_int (no range checking performed) + */ + +/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */ + +COMPILER_RT_ABI ti_int +__fixdfti(double a) +{ + double_bits fb; + fb.f = a; + int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023; + if (e < 0) + return 0; + ti_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31; + ti_int r = 0x0010000000000000uLL | (0x000FFFFFFFFFFFFFuLL & fb.u.all); + if (e > 52) + r <<= (e - 52); + else + r >>= (52 - e); + return (r ^ s) - s; +} + +#endif /* CRT_HAS_128BIT */ |