xref: /linux/arch/mips/math-emu/ieee754dp.h (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*
2  * IEEE754 floating point
3  * double precision internal header file
4  */
5 /*
6  * MIPS floating point support
7  * Copyright (C) 1994-2000 Algorithmics Ltd.
8  *
9  *  This program is free software; you can distribute it and/or modify it
10  *  under the terms of the GNU General Public License (Version 2) as
11  *  published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope it will be useful, but WITHOUT
14  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16  *  for more details.
17  *
18  *  You should have received a copy of the GNU General Public License along
19  *  with this program; if not, write to the Free Software Foundation, Inc.,
20  *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
21  */
22 
23 #include <linux/compiler.h>
24 
25 #include "ieee754int.h"
26 
27 #define assert(expr) ((void)0)
28 
29 #define DP_EBIAS	1023
30 #define DP_EMIN		(-1022)
31 #define DP_EMAX		1023
32 #define DP_FBITS	52
33 #define DP_MBITS	52
34 
35 #define DP_MBIT(x)	((u64)1 << (x))
36 #define DP_HIDDEN_BIT	DP_MBIT(DP_FBITS)
37 #define DP_SIGN_BIT	DP_MBIT(63)
38 
39 #define DPSIGN(dp)	(dp.sign)
40 #define DPBEXP(dp)	(dp.bexp)
41 #define DPMANT(dp)	(dp.mant)
42 
43 static inline int ieee754dp_finite(union ieee754dp x)
44 {
45 	return DPBEXP(x) != DP_EMAX + 1 + DP_EBIAS;
46 }
47 
48 /* 3bit extended double precision sticky right shift */
49 #define XDPSRS(v,rs)	\
50 	((rs > (DP_FBITS+3))?1:((v) >> (rs)) | ((v) << (64-(rs)) != 0))
51 
52 #define XDPSRSX1() \
53 	(xe++, (xm = (xm >> 1) | (xm & 1)))
54 
55 #define XDPSRS1(v)	\
56 	(((v) >> 1) | ((v) & 1))
57 
58 /* convert denormal to normalized with extended exponent */
59 #define DPDNORMx(m,e) \
60 	while ((m >> DP_FBITS) == 0) { m <<= 1; e--; }
61 #define DPDNORMX	DPDNORMx(xm, xe)
62 #define DPDNORMY	DPDNORMx(ym, ye)
63 
64 static inline union ieee754dp builddp(int s, int bx, u64 m)
65 {
66 	union ieee754dp r;
67 
68 	assert((s) == 0 || (s) == 1);
69 	assert((bx) >= DP_EMIN - 1 + DP_EBIAS
70 	       && (bx) <= DP_EMAX + 1 + DP_EBIAS);
71 	assert(((m) >> DP_FBITS) == 0);
72 
73 	r.sign = s;
74 	r.bexp = bx;
75 	r.mant = m;
76 
77 	return r;
78 }
79 
80 extern union ieee754dp __cold ieee754dp_nanxcpt(union ieee754dp);
81 extern union ieee754dp ieee754dp_format(int, int, u64);
82