1
2/*============================================================================
3
4This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
5Package, Release 3e, by John R. Hauser.
6
7Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017 The Regents of the
8University of California.  All rights reserved.
9
10Redistribution and use in source and binary forms, with or without
11modification, are permitted provided that the following conditions are met:
12
13 1. Redistributions of source code must retain the above copyright notice,
14    this list of conditions, and the following disclaimer.
15
16 2. Redistributions in binary form must reproduce the above copyright notice,
17    this list of conditions, and the following disclaimer in the documentation
18    and/or other materials provided with the distribution.
19
20 3. Neither the name of the University nor the names of its contributors may
21    be used to endorse or promote products derived from this software without
22    specific prior written permission.
23
24THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
25EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
27DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
28DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34
35=============================================================================*/
36
37#include <stdbool.h>
38#include <stdint.h>
39#include "platform.h"
40#include "internals.h"
41#include "specialize.h"
42#include "softfloat.h"
43
44int_fast64_t f64_to_i64( float64_t a, uint_fast8_t roundingMode, bool exact )
45{
46    union ui64_f64 uA;
47    uint_fast64_t uiA;
48    bool sign;
49    int_fast16_t exp;
50    uint_fast64_t sig;
51    int_fast16_t shiftDist;
52#ifdef SOFTFLOAT_FAST_INT64
53    struct uint64_extra sigExtra;
54#else
55    uint32_t extSig[3];
56#endif
57
58    /*------------------------------------------------------------------------
59    *------------------------------------------------------------------------*/
60    uA.f = a;
61    uiA = uA.ui;
62    sign = signF64UI( uiA );
63    exp  = expF64UI( uiA );
64    sig  = fracF64UI( uiA );
65    /*------------------------------------------------------------------------
66    *------------------------------------------------------------------------*/
67    if ( exp ) sig |= UINT64_C( 0x0010000000000000 );
68    shiftDist = 0x433 - exp;
69#ifdef SOFTFLOAT_FAST_INT64
70    if ( shiftDist <= 0 ) {
71        if ( shiftDist < -11 ) goto invalid;
72        sigExtra.v = sig<<-shiftDist;
73        sigExtra.extra = 0;
74    } else {
75        sigExtra = softfloat_shiftRightJam64Extra( sig, 0, shiftDist );
76    }
77    return
78        softfloat_roundToI64(
79            sign, sigExtra.v, sigExtra.extra, roundingMode, exact );
80#else
81    extSig[indexWord( 3, 0 )] = 0;
82    if ( shiftDist <= 0 ) {
83        if ( shiftDist < -11 ) goto invalid;
84        sig <<= -shiftDist;
85        extSig[indexWord( 3, 2 )] = sig>>32;
86        extSig[indexWord( 3, 1 )] = sig;
87    } else {
88        extSig[indexWord( 3, 2 )] = sig>>32;
89        extSig[indexWord( 3, 1 )] = sig;
90        softfloat_shiftRightJam96M( extSig, shiftDist, extSig );
91    }
92    return softfloat_roundMToI64( sign, extSig, roundingMode, exact );
93#endif
94    /*------------------------------------------------------------------------
95    *------------------------------------------------------------------------*/
96 invalid:
97    softfloat_raiseFlags( softfloat_flag_invalid );
98    return
99        (exp == 0x7FF) && fracF64UI( uiA ) ? i64_fromNaN
100            : sign ? i64_fromNegOverflow : i64_fromPosOverflow;
101
102}
103
104