diff options
Diffstat (limited to 'lib/fixdfti.c')
-rw-r--r-- | lib/fixdfti.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/lib/fixdfti.c b/lib/fixdfti.c new file mode 100644 index 000000000..94fc8d3d1 --- /dev/null +++ b/lib/fixdfti.c @@ -0,0 +1,43 @@ +//===-- fixdfti.c - Implement __fixdfti -----------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements __fixdfti for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#if __x86_64 + +#include "int_lib.h" + +// 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 + +ti_int +__fixdfti(double a) +{ + double_bits fb; + fb.f = a; + int e = ((fb.u.high & 0x7FF00000) >> 20) - 1023; + if (e < 0) + return 0; + ti_int s = (si_int)(fb.u.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 |