xref: /openbmc/linux/arch/mips/math-emu/ieee754sp.h (revision 727dede0)
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 SP_EBIAS	127
30 #define SP_EMIN		(-126)
31 #define SP_EMAX		127
32 #define SP_FBITS	23
33 #define SP_MBITS	23
34 
35 #define SP_MBIT(x)	((u32)1 << (x))
36 #define SP_HIDDEN_BIT	SP_MBIT(SP_FBITS)
37 #define SP_SIGN_BIT	SP_MBIT(31)
38 
39 #define SPSIGN(sp)	(sp.sign)
40 #define SPBEXP(sp)	(sp.bexp)
41 #define SPMANT(sp)	(sp.mant)
42 
43 static inline int ieee754sp_finite(union ieee754sp x)
44 {
45 	return SPBEXP(x) != SP_EMAX + 1 + SP_EBIAS;
46 }
47 
48 /* 64 bit right shift with rounding */
49 #define XSPSRS64(v, rs)						\
50 	(((rs) >= 64) ? ((v) != 0) : ((v) >> (rs)) | ((v) << (64-(rs)) != 0))
51 
52 /* 3bit extended single precision sticky right shift */
53 #define XSPSRS(v, rs)						\
54 	((rs > (SP_FBITS+3))?1:((v) >> (rs)) | ((v) << (32-(rs)) != 0))
55 
56 #define XSPSRS1(m) \
57 	((m >> 1) | (m & 1))
58 
59 #define SPXSRSX1() \
60 	(xe++, (xm = XSPSRS1(xm)))
61 
62 #define SPXSRSY1() \
63 	(ye++, (ym = XSPSRS1(ym)))
64 
65 /* convert denormal to normalized with extended exponent */
66 #define SPDNORMx(m,e) \
67 	while ((m >> SP_FBITS) == 0) { m <<= 1; e--; }
68 #define SPDNORMX	SPDNORMx(xm, xe)
69 #define SPDNORMY	SPDNORMx(ym, ye)
70 #define SPDNORMZ	SPDNORMx(zm, ze)
71 
72 static inline union ieee754sp buildsp(int s, int bx, unsigned m)
73 {
74 	union ieee754sp r;
75 
76 	assert((s) == 0 || (s) == 1);
77 	assert((bx) >= SP_EMIN - 1 + SP_EBIAS
78 	       && (bx) <= SP_EMAX + 1 + SP_EBIAS);
79 	assert(((m) >> SP_FBITS) == 0);
80 
81 	r.sign = s;
82 	r.bexp = bx;
83 	r.mant = m;
84 
85 	return r;
86 }
87 
88 extern union ieee754sp __cold ieee754sp_nanxcpt(union ieee754sp);
89 extern union ieee754sp ieee754sp_format(int, int, unsigned);
90