xref: /linux/arch/mips/math-emu/ieee754.h (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*
2  * MIPS floating point support
3  * Copyright (C) 1994-2000 Algorithmics Ltd.
4  *
5  *  This program is free software; you can distribute it and/or modify it
6  *  under the terms of the GNU General Public License (Version 2) as
7  *  published by the Free Software Foundation.
8  *
9  *  This program is distributed in the hope it will be useful, but WITHOUT
10  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  *  for more details.
13  *
14  *  You should have received a copy of the GNU General Public License along
15  *  with this program; if not, write to the Free Software Foundation, Inc.,
16  *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
17  *
18  *  Nov 7, 2000
19  *  Modification to allow integration with Linux kernel
20  *
21  *  Kevin D. Kissell, kevink@mips.com and Carsten Langgard, carstenl@mips.com
22  *  Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved.
23  */
24 #ifndef __ARCH_MIPS_MATH_EMU_IEEE754_H
25 #define __ARCH_MIPS_MATH_EMU_IEEE754_H
26 
27 #include <linux/compiler.h>
28 #include <asm/byteorder.h>
29 #include <linux/kernel.h>
30 #include <linux/types.h>
31 #include <linux/sched.h>
32 #include <asm/bitfield.h>
33 
34 union ieee754dp {
35 	struct {
36 		__BITFIELD_FIELD(unsigned int sign:1,
37 		__BITFIELD_FIELD(unsigned int bexp:11,
38 		__BITFIELD_FIELD(u64 mant:52,
39 		;)))
40 	};
41 	u64 bits;
42 };
43 
44 union ieee754sp {
45 	struct {
46 		__BITFIELD_FIELD(unsigned sign:1,
47 		__BITFIELD_FIELD(unsigned bexp:8,
48 		__BITFIELD_FIELD(unsigned mant:23,
49 		;)))
50 	};
51 	u32 bits;
52 };
53 
54 /*
55  * single precision (often aka float)
56 */
57 int ieee754sp_class(union ieee754sp x);
58 
59 union ieee754sp ieee754sp_abs(union ieee754sp x);
60 union ieee754sp ieee754sp_neg(union ieee754sp x);
61 
62 union ieee754sp ieee754sp_add(union ieee754sp x, union ieee754sp y);
63 union ieee754sp ieee754sp_sub(union ieee754sp x, union ieee754sp y);
64 union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y);
65 union ieee754sp ieee754sp_div(union ieee754sp x, union ieee754sp y);
66 
67 union ieee754sp ieee754sp_fint(int x);
68 union ieee754sp ieee754sp_flong(s64 x);
69 union ieee754sp ieee754sp_fdp(union ieee754dp x);
70 
71 int ieee754sp_tint(union ieee754sp x);
72 s64 ieee754sp_tlong(union ieee754sp x);
73 
74 int ieee754sp_cmp(union ieee754sp x, union ieee754sp y, int cop, int sig);
75 
76 union ieee754sp ieee754sp_sqrt(union ieee754sp x);
77 
78 /*
79  * double precision (often aka double)
80 */
81 int ieee754dp_class(union ieee754dp x);
82 
83 union ieee754dp ieee754dp_add(union ieee754dp x, union ieee754dp y);
84 union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y);
85 union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y);
86 union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y);
87 
88 union ieee754dp ieee754dp_abs(union ieee754dp x);
89 union ieee754dp ieee754dp_neg(union ieee754dp x);
90 
91 union ieee754dp ieee754dp_fint(int x);
92 union ieee754dp ieee754dp_flong(s64 x);
93 union ieee754dp ieee754dp_fsp(union ieee754sp x);
94 
95 int ieee754dp_tint(union ieee754dp x);
96 s64 ieee754dp_tlong(union ieee754dp x);
97 
98 int ieee754dp_cmp(union ieee754dp x, union ieee754dp y, int cop, int sig);
99 
100 union ieee754dp ieee754dp_sqrt(union ieee754dp x);
101 
102 
103 
104 /* 5 types of floating point number
105 */
106 enum {
107 	IEEE754_CLASS_NORM	= 0x00,
108 	IEEE754_CLASS_ZERO	= 0x01,
109 	IEEE754_CLASS_DNORM	= 0x02,
110 	IEEE754_CLASS_INF	= 0x03,
111 	IEEE754_CLASS_SNAN	= 0x04,
112 	IEEE754_CLASS_QNAN	= 0x05,
113 };
114 
115 /* exception numbers */
116 #define IEEE754_INEXACT			0x01
117 #define IEEE754_UNDERFLOW		0x02
118 #define IEEE754_OVERFLOW		0x04
119 #define IEEE754_ZERO_DIVIDE		0x08
120 #define IEEE754_INVALID_OPERATION	0x10
121 
122 /* cmp operators
123 */
124 #define IEEE754_CLT	0x01
125 #define IEEE754_CEQ	0x02
126 #define IEEE754_CGT	0x04
127 #define IEEE754_CUN	0x08
128 
129 /*
130  * The control status register
131  */
132 struct _ieee754_csr {
133 	__BITFIELD_FIELD(unsigned fcc:7,	/* condition[7:1] */
134 	__BITFIELD_FIELD(unsigned nod:1,	/* set 1 for no denormals */
135 	__BITFIELD_FIELD(unsigned c:1,		/* condition[0] */
136 	__BITFIELD_FIELD(unsigned pad0:3,
137 	__BITFIELD_FIELD(unsigned abs2008:1,	/* IEEE 754-2008 ABS/NEG.fmt */
138 	__BITFIELD_FIELD(unsigned nan2008:1,	/* IEEE 754-2008 NaN mode */
139 	__BITFIELD_FIELD(unsigned cx:6,		/* exceptions this operation */
140 	__BITFIELD_FIELD(unsigned mx:5,		/* exception enable  mask */
141 	__BITFIELD_FIELD(unsigned sx:5,		/* exceptions total */
142 	__BITFIELD_FIELD(unsigned rm:2,		/* current rounding mode */
143 	;))))))))))
144 };
145 #define ieee754_csr (*(struct _ieee754_csr *)(&current->thread.fpu.fcr31))
146 
147 static inline unsigned ieee754_getrm(void)
148 {
149 	return (ieee754_csr.rm);
150 }
151 static inline unsigned ieee754_setrm(unsigned rm)
152 {
153 	return (ieee754_csr.rm = rm);
154 }
155 
156 /*
157  * get current exceptions
158  */
159 static inline unsigned ieee754_getcx(void)
160 {
161 	return (ieee754_csr.cx);
162 }
163 
164 /* test for current exception condition
165  */
166 static inline int ieee754_cxtest(unsigned n)
167 {
168 	return (ieee754_csr.cx & n);
169 }
170 
171 /*
172  * get sticky exceptions
173  */
174 static inline unsigned ieee754_getsx(void)
175 {
176 	return (ieee754_csr.sx);
177 }
178 
179 /* clear sticky conditions
180 */
181 static inline unsigned ieee754_clrsx(void)
182 {
183 	return (ieee754_csr.sx = 0);
184 }
185 
186 /* test for sticky exception condition
187  */
188 static inline int ieee754_sxtest(unsigned n)
189 {
190 	return (ieee754_csr.sx & n);
191 }
192 
193 /* debugging */
194 union ieee754sp ieee754sp_dump(char *s, union ieee754sp x);
195 union ieee754dp ieee754dp_dump(char *s, union ieee754dp x);
196 
197 #define IEEE754_SPCVAL_PZERO		0	/* +0.0 */
198 #define IEEE754_SPCVAL_NZERO		1	/* -0.0 */
199 #define IEEE754_SPCVAL_PONE		2	/* +1.0 */
200 #define IEEE754_SPCVAL_NONE		3	/* -1.0 */
201 #define IEEE754_SPCVAL_PTEN		4	/* +10.0 */
202 #define IEEE754_SPCVAL_NTEN		5	/* -10.0 */
203 #define IEEE754_SPCVAL_PINFINITY	6	/* +inf */
204 #define IEEE754_SPCVAL_NINFINITY	7	/* -inf */
205 #define IEEE754_SPCVAL_INDEF		8	/* quiet NaN */
206 #define IEEE754_SPCVAL_PMAX		9	/* +max norm */
207 #define IEEE754_SPCVAL_NMAX		10	/* -max norm */
208 #define IEEE754_SPCVAL_PMIN		11	/* +min norm */
209 #define IEEE754_SPCVAL_NMIN		12	/* -min norm */
210 #define IEEE754_SPCVAL_PMIND		13	/* +min denorm */
211 #define IEEE754_SPCVAL_NMIND		14	/* -min denorm */
212 #define IEEE754_SPCVAL_P1E31		15	/* + 1.0e31 */
213 #define IEEE754_SPCVAL_P1E63		16	/* + 1.0e63 */
214 
215 extern const union ieee754dp __ieee754dp_spcvals[];
216 extern const union ieee754sp __ieee754sp_spcvals[];
217 #define ieee754dp_spcvals ((const union ieee754dp *)__ieee754dp_spcvals)
218 #define ieee754sp_spcvals ((const union ieee754sp *)__ieee754sp_spcvals)
219 
220 /*
221  * Return infinity with given sign
222  */
223 #define ieee754dp_inf(sn)     (ieee754dp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
224 #define ieee754dp_zero(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
225 #define ieee754dp_one(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
226 #define ieee754dp_ten(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
227 #define ieee754dp_indef()	(ieee754dp_spcvals[IEEE754_SPCVAL_INDEF])
228 #define ieee754dp_max(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
229 #define ieee754dp_min(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
230 #define ieee754dp_mind(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
231 #define ieee754dp_1e31()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E31])
232 #define ieee754dp_1e63()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E63])
233 
234 #define ieee754sp_inf(sn)     (ieee754sp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
235 #define ieee754sp_zero(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
236 #define ieee754sp_one(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
237 #define ieee754sp_ten(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
238 #define ieee754sp_indef()	(ieee754sp_spcvals[IEEE754_SPCVAL_INDEF])
239 #define ieee754sp_max(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
240 #define ieee754sp_min(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
241 #define ieee754sp_mind(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
242 #define ieee754sp_1e31()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E31])
243 #define ieee754sp_1e63()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E63])
244 
245 /*
246  * Indefinite integer value
247  */
248 static inline int ieee754si_indef(void)
249 {
250 	return INT_MAX;
251 }
252 
253 static inline s64 ieee754di_indef(void)
254 {
255 	return S64_MAX;
256 }
257 
258 /* result types for xctx.rt */
259 #define IEEE754_RT_SP	0
260 #define IEEE754_RT_DP	1
261 #define IEEE754_RT_XP	2
262 #define IEEE754_RT_SI	3
263 #define IEEE754_RT_DI	4
264 
265 /* compat */
266 #define ieee754dp_fix(x)	ieee754dp_tint(x)
267 #define ieee754sp_fix(x)	ieee754sp_tint(x)
268 
269 #endif /* __ARCH_MIPS_MATH_EMU_IEEE754_H */
270