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 The Regents of the University of
8California.  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 f128_to_i64_r_minMag( float128_t a, bool exact )
45{
46    union ui128_f128 uA;
47    uint_fast64_t uiA64, uiA0;
48    bool sign;
49    int_fast32_t exp;
50    uint_fast64_t sig64, sig0;
51    int_fast32_t shiftDist;
52    int_fast8_t negShiftDist;
53    int_fast64_t absZ;
54
55    /*------------------------------------------------------------------------
56    *------------------------------------------------------------------------*/
57    uA.f = a;
58    uiA64 = uA.ui.v64;
59    uiA0  = uA.ui.v0;
60    sign  = signF128UI64( uiA64 );
61    exp   = expF128UI64( uiA64 );
62    sig64 = fracF128UI64( uiA64 );
63    sig0  = uiA0;
64    /*------------------------------------------------------------------------
65    *------------------------------------------------------------------------*/
66    shiftDist = 0x402F - exp;
67    if ( shiftDist < 0 ) {
68        /*--------------------------------------------------------------------
69        *--------------------------------------------------------------------*/
70        if ( shiftDist < -14 ) {
71            if (
72                   (uiA64 == UINT64_C( 0xC03E000000000000 ))
73                && (sig0 < UINT64_C( 0x0002000000000000 ))
74            ) {
75                if ( exact && sig0 ) {
76                    softfloat_raiseFlags( softfloat_flag_inexact );
77                }
78                return -INT64_C( 0x7FFFFFFFFFFFFFFF ) - 1;
79            }
80            softfloat_raiseFlags( softfloat_flag_invalid );
81            return
82                (exp == 0x7FFF) && (sig64 | sig0) ? i64_fromNaN
83                    : sign ? i64_fromNegOverflow : i64_fromPosOverflow;
84        }
85        /*--------------------------------------------------------------------
86        *--------------------------------------------------------------------*/
87        sig64 |= UINT64_C( 0x0001000000000000 );
88        negShiftDist = -shiftDist;
89        absZ = sig64<<negShiftDist | sig0>>(shiftDist & 63);
90        if ( exact && (uint64_t) (sig0<<negShiftDist) ) {
91            softfloat_raiseFlags( softfloat_flag_inexact );
92        }
93    } else {
94        /*--------------------------------------------------------------------
95        *--------------------------------------------------------------------*/
96        if ( 49 <= shiftDist ) {
97            if ( exact && (exp | sig64 | sig0) ) {
98                softfloat_raiseFlags( softfloat_flag_inexact );
99            }
100            return 0;
101        }
102        /*--------------------------------------------------------------------
103        *--------------------------------------------------------------------*/
104        sig64 |= UINT64_C( 0x0001000000000000 );
105        absZ = sig64>>shiftDist;
106        if ( exact && (sig0 || (absZ<<shiftDist != sig64)) ) {
107            softfloat_raiseFlags( softfloat_flag_inexact );
108        }
109    }
110    return sign ? -absZ : absZ;
111
112}
113
114