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Diffstat (limited to 'lib/fixsfti.c')
-rw-r--r-- | lib/fixsfti.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/lib/fixsfti.c b/lib/fixsfti.c new file mode 100644 index 000000000..8e3958757 --- /dev/null +++ b/lib/fixsfti.c @@ -0,0 +1,43 @@ +//===-- fixsfti.c - Implement __fixsfti -----------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements __fixsfti for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#if __x86_64 + +#include "int_lib.h" + +// Returns: convert a to a signed long long, rounding toward zero. + +// Assumption: float is a IEEE 32 bit floating point type +// su_int is a 32 bit integral type +// value in float is representable in ti_int (no range checking performed) + +// seee eeee emmm mmmm mmmm mmmm mmmm mmmm + +ti_int +__fixsfti(float a) +{ + float_bits fb; + fb.f = a; + int e = ((fb.u & 0x7F800000) >> 23) - 127; + if (e < 0) + return 0; + ti_int s = (si_int)(fb.u & 0x80000000) >> 31; + ti_int r = (fb.u & 0x007FFFFF) | 0x00800000; + if (e > 23) + r <<= (e - 23); + else + r >>= (23 - e); + return (r ^ s) - s; +} + +#endif |