xref: /linux/arch/mips/math-emu/ieee754.h (revision b3fea962)
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 /* "normal" comparisons
130 */
131 static inline int ieee754sp_eq(union ieee754sp x, union ieee754sp y)
132 {
133 	return ieee754sp_cmp(x, y, IEEE754_CEQ, 0);
134 }
135 
136 static inline int ieee754sp_ne(union ieee754sp x, union ieee754sp y)
137 {
138 	return ieee754sp_cmp(x, y,
139 			     IEEE754_CLT | IEEE754_CGT | IEEE754_CUN, 0);
140 }
141 
142 static inline int ieee754sp_lt(union ieee754sp x, union ieee754sp y)
143 {
144 	return ieee754sp_cmp(x, y, IEEE754_CLT, 0);
145 }
146 
147 static inline int ieee754sp_le(union ieee754sp x, union ieee754sp y)
148 {
149 	return ieee754sp_cmp(x, y, IEEE754_CLT | IEEE754_CEQ, 0);
150 }
151 
152 static inline int ieee754sp_gt(union ieee754sp x, union ieee754sp y)
153 {
154 	return ieee754sp_cmp(x, y, IEEE754_CGT, 0);
155 }
156 
157 
158 static inline int ieee754sp_ge(union ieee754sp x, union ieee754sp y)
159 {
160 	return ieee754sp_cmp(x, y, IEEE754_CGT | IEEE754_CEQ, 0);
161 }
162 
163 static inline int ieee754dp_eq(union ieee754dp x, union ieee754dp y)
164 {
165 	return ieee754dp_cmp(x, y, IEEE754_CEQ, 0);
166 }
167 
168 static inline int ieee754dp_ne(union ieee754dp x, union ieee754dp y)
169 {
170 	return ieee754dp_cmp(x, y,
171 			     IEEE754_CLT | IEEE754_CGT | IEEE754_CUN, 0);
172 }
173 
174 static inline int ieee754dp_lt(union ieee754dp x, union ieee754dp y)
175 {
176 	return ieee754dp_cmp(x, y, IEEE754_CLT, 0);
177 }
178 
179 static inline int ieee754dp_le(union ieee754dp x, union ieee754dp y)
180 {
181 	return ieee754dp_cmp(x, y, IEEE754_CLT | IEEE754_CEQ, 0);
182 }
183 
184 static inline int ieee754dp_gt(union ieee754dp x, union ieee754dp y)
185 {
186 	return ieee754dp_cmp(x, y, IEEE754_CGT, 0);
187 }
188 
189 static inline int ieee754dp_ge(union ieee754dp x, union ieee754dp y)
190 {
191 	return ieee754dp_cmp(x, y, IEEE754_CGT | IEEE754_CEQ, 0);
192 }
193 
194 /*
195  * The control status register
196  */
197 struct _ieee754_csr {
198 	__BITFIELD_FIELD(unsigned pad0:7,
199 	__BITFIELD_FIELD(unsigned nod:1,	/* set 1 for no denormalised numbers */
200 	__BITFIELD_FIELD(unsigned c:1,		/* condition */
201 	__BITFIELD_FIELD(unsigned pad1:5,
202 	__BITFIELD_FIELD(unsigned cx:6,		/* exceptions this operation */
203 	__BITFIELD_FIELD(unsigned mx:5,		/* exception enable  mask */
204 	__BITFIELD_FIELD(unsigned sx:5,		/* exceptions total */
205 	__BITFIELD_FIELD(unsigned rm:2,		/* current rounding mode */
206 	;))))))))
207 };
208 #define ieee754_csr (*(struct _ieee754_csr *)(&current->thread.fpu.fcr31))
209 
210 static inline unsigned ieee754_getrm(void)
211 {
212 	return (ieee754_csr.rm);
213 }
214 static inline unsigned ieee754_setrm(unsigned rm)
215 {
216 	return (ieee754_csr.rm = rm);
217 }
218 
219 /*
220  * get current exceptions
221  */
222 static inline unsigned ieee754_getcx(void)
223 {
224 	return (ieee754_csr.cx);
225 }
226 
227 /* test for current exception condition
228  */
229 static inline int ieee754_cxtest(unsigned n)
230 {
231 	return (ieee754_csr.cx & n);
232 }
233 
234 /*
235  * get sticky exceptions
236  */
237 static inline unsigned ieee754_getsx(void)
238 {
239 	return (ieee754_csr.sx);
240 }
241 
242 /* clear sticky conditions
243 */
244 static inline unsigned ieee754_clrsx(void)
245 {
246 	return (ieee754_csr.sx = 0);
247 }
248 
249 /* test for sticky exception condition
250  */
251 static inline int ieee754_sxtest(unsigned n)
252 {
253 	return (ieee754_csr.sx & n);
254 }
255 
256 /* debugging */
257 union ieee754sp ieee754sp_dump(char *s, union ieee754sp x);
258 union ieee754dp ieee754dp_dump(char *s, union ieee754dp x);
259 
260 #define IEEE754_SPCVAL_PZERO	0
261 #define IEEE754_SPCVAL_NZERO	1
262 #define IEEE754_SPCVAL_PONE	2
263 #define IEEE754_SPCVAL_NONE	3
264 #define IEEE754_SPCVAL_PTEN	4
265 #define IEEE754_SPCVAL_NTEN	5
266 #define IEEE754_SPCVAL_PINFINITY	6
267 #define IEEE754_SPCVAL_NINFINITY	7
268 #define IEEE754_SPCVAL_INDEF	8
269 #define IEEE754_SPCVAL_PMAX	9	/* +max norm */
270 #define IEEE754_SPCVAL_NMAX	10	/* -max norm */
271 #define IEEE754_SPCVAL_PMIN	11	/* +min norm */
272 #define IEEE754_SPCVAL_NMIN	12	/* -min norm */
273 #define IEEE754_SPCVAL_PMIND	13	/* +min denorm */
274 #define IEEE754_SPCVAL_NMIND	14	/* -min denorm */
275 #define IEEE754_SPCVAL_P1E31	15	/* + 1.0e31 */
276 #define IEEE754_SPCVAL_P1E63	16	/* + 1.0e63 */
277 
278 extern const union ieee754dp __ieee754dp_spcvals[];
279 extern const union ieee754sp __ieee754sp_spcvals[];
280 #define ieee754dp_spcvals ((const union ieee754dp *)__ieee754dp_spcvals)
281 #define ieee754sp_spcvals ((const union ieee754sp *)__ieee754sp_spcvals)
282 
283 /*
284  * Return infinity with given sign
285  */
286 #define ieee754dp_inf(sn)     (ieee754dp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
287 #define ieee754dp_zero(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
288 #define ieee754dp_one(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
289 #define ieee754dp_ten(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
290 #define ieee754dp_indef()	(ieee754dp_spcvals[IEEE754_SPCVAL_INDEF])
291 #define ieee754dp_max(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
292 #define ieee754dp_min(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
293 #define ieee754dp_mind(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
294 #define ieee754dp_1e31()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E31])
295 #define ieee754dp_1e63()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E63])
296 
297 #define ieee754sp_inf(sn)     (ieee754sp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
298 #define ieee754sp_zero(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
299 #define ieee754sp_one(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
300 #define ieee754sp_ten(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
301 #define ieee754sp_indef()	(ieee754sp_spcvals[IEEE754_SPCVAL_INDEF])
302 #define ieee754sp_max(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
303 #define ieee754sp_min(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
304 #define ieee754sp_mind(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
305 #define ieee754sp_1e31()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E31])
306 #define ieee754sp_1e63()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E63])
307 
308 /*
309  * Indefinite integer value
310  */
311 static inline int ieee754si_indef(void)
312 {
313 	return INT_MAX;
314 }
315 
316 static inline s64 ieee754di_indef(void)
317 {
318 	return S64_MAX;
319 }
320 
321 /* result types for xctx.rt */
322 #define IEEE754_RT_SP	0
323 #define IEEE754_RT_DP	1
324 #define IEEE754_RT_XP	2
325 #define IEEE754_RT_SI	3
326 #define IEEE754_RT_DI	4
327 
328 /* compat */
329 #define ieee754dp_fix(x)	ieee754dp_tint(x)
330 #define ieee754sp_fix(x)	ieee754sp_tint(x)
331 
332 #endif /* __ARCH_MIPS_MATH_EMU_IEEE754_H */
333