1 //===-- lib/fixdfsi.c - Double-precision -> integer conversion ----*- C -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements double-precision to integer conversion for the
11 // compiler-rt library. No range checking is performed; the behavior of this
12 // conversion is undefined for out of range values in the C standard.
14 //===----------------------------------------------------------------------===//
16 #define DOUBLE_PRECISION
21 ARM_EABI_FNALIAS(d2iz
, fixdfsi
)
26 // Break a into sign, exponent, significand
27 const rep_t aRep
= toRep(a
);
28 const rep_t aAbs
= aRep
& absMask
;
29 const int sign
= aRep
& signBit
? -1 : 1;
30 const int exponent
= (aAbs
>> significandBits
) - exponentBias
;
31 const rep_t significand
= (aAbs
& significandMask
) | implicitBit
;
33 // If 0 < exponent < significandBits, right shift to get the result.
34 if ((unsigned int)exponent
< significandBits
) {
35 return sign
* (significand
>> (significandBits
- exponent
));
38 // If exponent is negative, the result is zero.
39 else if (exponent
< 0) {
43 // If significandBits < exponent, left shift to get the result. This shift
44 // may end up being larger than the type width, which incurs undefined
45 // behavior, but the conversion itself is undefined in that case, so
46 // whatever the compiler decides to do is fine.
48 return sign
* (significand
<< (exponent
- significandBits
));