xref: /openbmc/linux/arch/mips/math-emu/ieee754.h (revision 4a3fad70)
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 union ieee754sp ieee754sp_rint(union ieee754sp x);
71 
72 int ieee754sp_tint(union ieee754sp x);
73 s64 ieee754sp_tlong(union ieee754sp x);
74 
75 int ieee754sp_cmp(union ieee754sp x, union ieee754sp y, int cop, int sig);
76 
77 union ieee754sp ieee754sp_sqrt(union ieee754sp x);
78 
79 union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
80 				union ieee754sp y);
81 union ieee754sp ieee754sp_msubf(union ieee754sp z, union ieee754sp x,
82 				union ieee754sp y);
83 int ieee754sp_2008class(union ieee754sp x);
84 union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y);
85 union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y);
86 union ieee754sp ieee754sp_fmax(union ieee754sp x, union ieee754sp y);
87 union ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y);
88 
89 /*
90  * double precision (often aka double)
91 */
92 int ieee754dp_class(union ieee754dp x);
93 
94 union ieee754dp ieee754dp_add(union ieee754dp x, union ieee754dp y);
95 union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y);
96 union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y);
97 union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y);
98 
99 union ieee754dp ieee754dp_abs(union ieee754dp x);
100 union ieee754dp ieee754dp_neg(union ieee754dp x);
101 
102 union ieee754dp ieee754dp_fint(int x);
103 union ieee754dp ieee754dp_flong(s64 x);
104 union ieee754dp ieee754dp_fsp(union ieee754sp x);
105 union ieee754dp ieee754dp_rint(union ieee754dp x);
106 
107 int ieee754dp_tint(union ieee754dp x);
108 s64 ieee754dp_tlong(union ieee754dp x);
109 
110 int ieee754dp_cmp(union ieee754dp x, union ieee754dp y, int cop, int sig);
111 
112 union ieee754dp ieee754dp_sqrt(union ieee754dp x);
113 
114 union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x,
115 				union ieee754dp y);
116 union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x,
117 				union ieee754dp y);
118 int ieee754dp_2008class(union ieee754dp x);
119 union ieee754dp ieee754dp_fmin(union ieee754dp x, union ieee754dp y);
120 union ieee754dp ieee754dp_fmina(union ieee754dp x, union ieee754dp y);
121 union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y);
122 union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y);
123 
124 
125 /* 5 types of floating point number
126 */
127 enum {
128 	IEEE754_CLASS_NORM	= 0x00,
129 	IEEE754_CLASS_ZERO	= 0x01,
130 	IEEE754_CLASS_DNORM	= 0x02,
131 	IEEE754_CLASS_INF	= 0x03,
132 	IEEE754_CLASS_SNAN	= 0x04,
133 	IEEE754_CLASS_QNAN	= 0x05,
134 };
135 
136 /* exception numbers */
137 #define IEEE754_INEXACT			0x01
138 #define IEEE754_UNDERFLOW		0x02
139 #define IEEE754_OVERFLOW		0x04
140 #define IEEE754_ZERO_DIVIDE		0x08
141 #define IEEE754_INVALID_OPERATION	0x10
142 
143 /* cmp operators
144 */
145 #define IEEE754_CLT	0x01
146 #define IEEE754_CEQ	0x02
147 #define IEEE754_CGT	0x04
148 #define IEEE754_CUN	0x08
149 
150 /*
151  * The control status register
152  */
153 struct _ieee754_csr {
154 	__BITFIELD_FIELD(unsigned fcc:7,	/* condition[7:1] */
155 	__BITFIELD_FIELD(unsigned nod:1,	/* set 1 for no denormals */
156 	__BITFIELD_FIELD(unsigned c:1,		/* condition[0] */
157 	__BITFIELD_FIELD(unsigned pad0:3,
158 	__BITFIELD_FIELD(unsigned abs2008:1,	/* IEEE 754-2008 ABS/NEG.fmt */
159 	__BITFIELD_FIELD(unsigned nan2008:1,	/* IEEE 754-2008 NaN mode */
160 	__BITFIELD_FIELD(unsigned cx:6,		/* exceptions this operation */
161 	__BITFIELD_FIELD(unsigned mx:5,		/* exception enable  mask */
162 	__BITFIELD_FIELD(unsigned sx:5,		/* exceptions total */
163 	__BITFIELD_FIELD(unsigned rm:2,		/* current rounding mode */
164 	;))))))))))
165 };
166 #define ieee754_csr (*(struct _ieee754_csr *)(&current->thread.fpu.fcr31))
167 
168 static inline unsigned int ieee754_getrm(void)
169 {
170 	return (ieee754_csr.rm);
171 }
172 
173 static inline unsigned int ieee754_setrm(unsigned int rm)
174 {
175 	return (ieee754_csr.rm = rm);
176 }
177 
178 /*
179  * get current exceptions
180  */
181 static inline unsigned int ieee754_getcx(void)
182 {
183 	return (ieee754_csr.cx);
184 }
185 
186 /* test for current exception condition
187  */
188 static inline int ieee754_cxtest(unsigned int n)
189 {
190 	return (ieee754_csr.cx & n);
191 }
192 
193 /*
194  * get sticky exceptions
195  */
196 static inline unsigned int ieee754_getsx(void)
197 {
198 	return (ieee754_csr.sx);
199 }
200 
201 /* clear sticky conditions
202 */
203 static inline unsigned int ieee754_clrsx(void)
204 {
205 	return (ieee754_csr.sx = 0);
206 }
207 
208 /* test for sticky exception condition
209  */
210 static inline int ieee754_sxtest(unsigned int n)
211 {
212 	return (ieee754_csr.sx & n);
213 }
214 
215 /* debugging */
216 union ieee754sp ieee754sp_dump(char *s, union ieee754sp x);
217 union ieee754dp ieee754dp_dump(char *s, union ieee754dp x);
218 
219 #define IEEE754_SPCVAL_PZERO		0	/* +0.0 */
220 #define IEEE754_SPCVAL_NZERO		1	/* -0.0 */
221 #define IEEE754_SPCVAL_PONE		2	/* +1.0 */
222 #define IEEE754_SPCVAL_NONE		3	/* -1.0 */
223 #define IEEE754_SPCVAL_PTEN		4	/* +10.0 */
224 #define IEEE754_SPCVAL_NTEN		5	/* -10.0 */
225 #define IEEE754_SPCVAL_PINFINITY	6	/* +inf */
226 #define IEEE754_SPCVAL_NINFINITY	7	/* -inf */
227 #define IEEE754_SPCVAL_INDEF_LEG	8	/* legacy quiet NaN */
228 #define IEEE754_SPCVAL_INDEF_2008	9	/* IEEE 754-2008 quiet NaN */
229 #define IEEE754_SPCVAL_PMAX		10	/* +max norm */
230 #define IEEE754_SPCVAL_NMAX		11	/* -max norm */
231 #define IEEE754_SPCVAL_PMIN		12	/* +min norm */
232 #define IEEE754_SPCVAL_NMIN		13	/* -min norm */
233 #define IEEE754_SPCVAL_PMIND		14	/* +min denorm */
234 #define IEEE754_SPCVAL_NMIND		15	/* -min denorm */
235 #define IEEE754_SPCVAL_P1E31		16	/* + 1.0e31 */
236 #define IEEE754_SPCVAL_P1E63		17	/* + 1.0e63 */
237 
238 extern const union ieee754dp __ieee754dp_spcvals[];
239 extern const union ieee754sp __ieee754sp_spcvals[];
240 #define ieee754dp_spcvals ((const union ieee754dp *)__ieee754dp_spcvals)
241 #define ieee754sp_spcvals ((const union ieee754sp *)__ieee754sp_spcvals)
242 
243 /*
244  * Return infinity with given sign
245  */
246 #define ieee754dp_inf(sn)     (ieee754dp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
247 #define ieee754dp_zero(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
248 #define ieee754dp_one(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
249 #define ieee754dp_ten(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
250 #define ieee754dp_indef()	(ieee754dp_spcvals[IEEE754_SPCVAL_INDEF_LEG + \
251 						   ieee754_csr.nan2008])
252 #define ieee754dp_max(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
253 #define ieee754dp_min(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
254 #define ieee754dp_mind(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
255 #define ieee754dp_1e31()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E31])
256 #define ieee754dp_1e63()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E63])
257 
258 #define ieee754sp_inf(sn)     (ieee754sp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
259 #define ieee754sp_zero(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
260 #define ieee754sp_one(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
261 #define ieee754sp_ten(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
262 #define ieee754sp_indef()	(ieee754sp_spcvals[IEEE754_SPCVAL_INDEF_LEG + \
263 						   ieee754_csr.nan2008])
264 #define ieee754sp_max(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
265 #define ieee754sp_min(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
266 #define ieee754sp_mind(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
267 #define ieee754sp_1e31()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E31])
268 #define ieee754sp_1e63()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E63])
269 
270 /*
271  * Indefinite integer value
272  */
273 static inline int ieee754si_indef(void)
274 {
275 	return ieee754_csr.nan2008 ? 0 : INT_MAX;
276 }
277 
278 static inline s64 ieee754di_indef(void)
279 {
280 	return ieee754_csr.nan2008 ? 0 : S64_MAX;
281 }
282 
283 /*
284  * Overflow integer value
285  */
286 static inline int ieee754si_overflow(int xs)
287 {
288 	return ieee754_csr.nan2008 && xs ? INT_MIN : INT_MAX;
289 }
290 
291 static inline s64 ieee754di_overflow(int xs)
292 {
293 	return ieee754_csr.nan2008 && xs ? S64_MIN : S64_MAX;
294 }
295 
296 /* result types for xctx.rt */
297 #define IEEE754_RT_SP	0
298 #define IEEE754_RT_DP	1
299 #define IEEE754_RT_XP	2
300 #define IEEE754_RT_SI	3
301 #define IEEE754_RT_DI	4
302 
303 /* compat */
304 #define ieee754dp_fix(x)	ieee754dp_tint(x)
305 #define ieee754sp_fix(x)	ieee754sp_tint(x)
306 
307 #endif /* __ARCH_MIPS_MATH_EMU_IEEE754_H */
308