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1da177e4 LT |
1 | /* IEEE754 floating point arithmetic |
2 | * single precision | |
3 | */ | |
4 | /* | |
5 | * MIPS floating point support | |
6 | * Copyright (C) 1994-2000 Algorithmics Ltd. | |
7 | * http://www.algor.co.uk | |
8 | * | |
9 | * ######################################################################## | |
10 | * | |
11 | * This program is free software; you can distribute it and/or modify it | |
12 | * under the terms of the GNU General Public License (Version 2) as | |
13 | * published by the Free Software Foundation. | |
14 | * | |
15 | * This program is distributed in the hope it will be useful, but WITHOUT | |
16 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
17 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
18 | * for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License along | |
21 | * with this program; if not, write to the Free Software Foundation, Inc., | |
22 | * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. | |
23 | * | |
24 | * ######################################################################## | |
25 | */ | |
26 | ||
27 | ||
28 | #include "ieee754sp.h" | |
29 | ||
30 | ieee754sp ieee754sp_fdp(ieee754dp x) | |
31 | { | |
32 | COMPXDP; | |
33 | ieee754sp nan; | |
34 | ||
35 | EXPLODEXDP; | |
36 | ||
37 | CLEARCX; | |
38 | ||
39 | FLUSHXDP; | |
40 | ||
41 | switch (xc) { | |
42 | case IEEE754_CLASS_SNAN: | |
43 | SETCX(IEEE754_INVALID_OPERATION); | |
44 | return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp"); | |
45 | case IEEE754_CLASS_QNAN: | |
46 | nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32) | |
47 | (xm >> (DP_MBITS - SP_MBITS))); | |
48 | if (!ieee754sp_isnan(nan)) | |
49 | nan = ieee754sp_indef(); | |
50 | return ieee754sp_nanxcpt(nan, "fdp", x); | |
51 | case IEEE754_CLASS_INF: | |
52 | return ieee754sp_inf(xs); | |
53 | case IEEE754_CLASS_ZERO: | |
54 | return ieee754sp_zero(xs); | |
55 | case IEEE754_CLASS_DNORM: | |
56 | /* can't possibly be sp representable */ | |
57 | SETCX(IEEE754_UNDERFLOW); | |
58 | SETCX(IEEE754_INEXACT); | |
59 | if ((ieee754_csr.rm == IEEE754_RU && !xs) || | |
60 | (ieee754_csr.rm == IEEE754_RD && xs)) | |
61 | return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x); | |
62 | return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x); | |
63 | case IEEE754_CLASS_NORM: | |
64 | break; | |
65 | } | |
66 | ||
67 | { | |
68 | u32 rm; | |
69 | ||
70 | /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift | |
71 | */ | |
72 | rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) | | |
73 | ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0); | |
74 | ||
75 | SPNORMRET1(xs, xe, rm, "fdp", x); | |
76 | } | |
77 | } |