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Diffstat (limited to 'lib/fixunsxfti.c')
-rw-r--r-- | lib/fixunsxfti.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/fixunsxfti.c b/lib/fixunsxfti.c new file mode 100644 index 000000000..993594dfa --- /dev/null +++ b/lib/fixunsxfti.c @@ -0,0 +1,45 @@ +//===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements __fixunsxfti for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#if __x86_64 + +#include "int_lib.h" + +// Returns: convert a to a unsigned long long, rounding toward zero. +// Negative values all become zero. + +// Assumption: long double is an intel 80 bit floating point type padded with 6 bytes +// tu_int is a 64 bit integral type +// value in long double is representable in tu_int or is negative +// (no range checking performed) + +// 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 + +tu_int +__fixunsxfti(long double a) +{ + long_double_bits fb; + fb.f = a; + int e = (fb.u.high.low & 0x00007FFF) - 16383; + if (e < 0 || (fb.u.high.low & 0x00008000)) + return 0; + tu_int r = fb.u.low.all; + if (e > 63) + r <<= (e - 63); + else + r >>= (63 - e); + return r; +} + +#endif |