xref: /openbmc/linux/arch/mips/math-emu/ieee754.h (revision f3539c12)
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 union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
79 				union ieee754sp y);
80 union ieee754sp ieee754sp_msubf(union ieee754sp z, union ieee754sp x,
81 				union ieee754sp y);
82 int ieee754sp_2008class(union ieee754sp x);
83 union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y);
84 union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y);
85 union ieee754sp ieee754sp_fmax(union ieee754sp x, union ieee754sp y);
86 union ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y);
87 
88 /*
89  * double precision (often aka double)
90 */
91 int ieee754dp_class(union ieee754dp x);
92 
93 union ieee754dp ieee754dp_add(union ieee754dp x, union ieee754dp y);
94 union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y);
95 union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y);
96 union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y);
97 
98 union ieee754dp ieee754dp_abs(union ieee754dp x);
99 union ieee754dp ieee754dp_neg(union ieee754dp x);
100 
101 union ieee754dp ieee754dp_fint(int x);
102 union ieee754dp ieee754dp_flong(s64 x);
103 union ieee754dp ieee754dp_fsp(union ieee754sp x);
104 
105 int ieee754dp_tint(union ieee754dp x);
106 s64 ieee754dp_tlong(union ieee754dp x);
107 
108 int ieee754dp_cmp(union ieee754dp x, union ieee754dp y, int cop, int sig);
109 
110 union ieee754dp ieee754dp_sqrt(union ieee754dp x);
111 
112 union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x,
113 				union ieee754dp y);
114 union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x,
115 				union ieee754dp y);
116 int ieee754dp_2008class(union ieee754dp x);
117 union ieee754dp ieee754dp_fmin(union ieee754dp x, union ieee754dp y);
118 union ieee754dp ieee754dp_fmina(union ieee754dp x, union ieee754dp y);
119 union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y);
120 union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y);
121 
122 
123 /* 5 types of floating point number
124 */
125 enum {
126 	IEEE754_CLASS_NORM	= 0x00,
127 	IEEE754_CLASS_ZERO	= 0x01,
128 	IEEE754_CLASS_DNORM	= 0x02,
129 	IEEE754_CLASS_INF	= 0x03,
130 	IEEE754_CLASS_SNAN	= 0x04,
131 	IEEE754_CLASS_QNAN	= 0x05,
132 };
133 
134 /* exception numbers */
135 #define IEEE754_INEXACT			0x01
136 #define IEEE754_UNDERFLOW		0x02
137 #define IEEE754_OVERFLOW		0x04
138 #define IEEE754_ZERO_DIVIDE		0x08
139 #define IEEE754_INVALID_OPERATION	0x10
140 
141 /* cmp operators
142 */
143 #define IEEE754_CLT	0x01
144 #define IEEE754_CEQ	0x02
145 #define IEEE754_CGT	0x04
146 #define IEEE754_CUN	0x08
147 
148 /*
149  * The control status register
150  */
151 struct _ieee754_csr {
152 	__BITFIELD_FIELD(unsigned fcc:7,	/* condition[7:1] */
153 	__BITFIELD_FIELD(unsigned nod:1,	/* set 1 for no denormals */
154 	__BITFIELD_FIELD(unsigned c:1,		/* condition[0] */
155 	__BITFIELD_FIELD(unsigned pad0:3,
156 	__BITFIELD_FIELD(unsigned abs2008:1,	/* IEEE 754-2008 ABS/NEG.fmt */
157 	__BITFIELD_FIELD(unsigned nan2008:1,	/* IEEE 754-2008 NaN mode */
158 	__BITFIELD_FIELD(unsigned cx:6,		/* exceptions this operation */
159 	__BITFIELD_FIELD(unsigned mx:5,		/* exception enable  mask */
160 	__BITFIELD_FIELD(unsigned sx:5,		/* exceptions total */
161 	__BITFIELD_FIELD(unsigned rm:2,		/* current rounding mode */
162 	;))))))))))
163 };
164 #define ieee754_csr (*(struct _ieee754_csr *)(&current->thread.fpu.fcr31))
165 
166 static inline unsigned ieee754_getrm(void)
167 {
168 	return (ieee754_csr.rm);
169 }
170 static inline unsigned ieee754_setrm(unsigned rm)
171 {
172 	return (ieee754_csr.rm = rm);
173 }
174 
175 /*
176  * get current exceptions
177  */
178 static inline unsigned ieee754_getcx(void)
179 {
180 	return (ieee754_csr.cx);
181 }
182 
183 /* test for current exception condition
184  */
185 static inline int ieee754_cxtest(unsigned n)
186 {
187 	return (ieee754_csr.cx & n);
188 }
189 
190 /*
191  * get sticky exceptions
192  */
193 static inline unsigned ieee754_getsx(void)
194 {
195 	return (ieee754_csr.sx);
196 }
197 
198 /* clear sticky conditions
199 */
200 static inline unsigned ieee754_clrsx(void)
201 {
202 	return (ieee754_csr.sx = 0);
203 }
204 
205 /* test for sticky exception condition
206  */
207 static inline int ieee754_sxtest(unsigned n)
208 {
209 	return (ieee754_csr.sx & n);
210 }
211 
212 /* debugging */
213 union ieee754sp ieee754sp_dump(char *s, union ieee754sp x);
214 union ieee754dp ieee754dp_dump(char *s, union ieee754dp x);
215 
216 #define IEEE754_SPCVAL_PZERO		0	/* +0.0 */
217 #define IEEE754_SPCVAL_NZERO		1	/* -0.0 */
218 #define IEEE754_SPCVAL_PONE		2	/* +1.0 */
219 #define IEEE754_SPCVAL_NONE		3	/* -1.0 */
220 #define IEEE754_SPCVAL_PTEN		4	/* +10.0 */
221 #define IEEE754_SPCVAL_NTEN		5	/* -10.0 */
222 #define IEEE754_SPCVAL_PINFINITY	6	/* +inf */
223 #define IEEE754_SPCVAL_NINFINITY	7	/* -inf */
224 #define IEEE754_SPCVAL_INDEF_LEG	8	/* legacy quiet NaN */
225 #define IEEE754_SPCVAL_INDEF_2008	9	/* IEEE 754-2008 quiet NaN */
226 #define IEEE754_SPCVAL_PMAX		10	/* +max norm */
227 #define IEEE754_SPCVAL_NMAX		11	/* -max norm */
228 #define IEEE754_SPCVAL_PMIN		12	/* +min norm */
229 #define IEEE754_SPCVAL_NMIN		13	/* -min norm */
230 #define IEEE754_SPCVAL_PMIND		14	/* +min denorm */
231 #define IEEE754_SPCVAL_NMIND		15	/* -min denorm */
232 #define IEEE754_SPCVAL_P1E31		16	/* + 1.0e31 */
233 #define IEEE754_SPCVAL_P1E63		17	/* + 1.0e63 */
234 
235 extern const union ieee754dp __ieee754dp_spcvals[];
236 extern const union ieee754sp __ieee754sp_spcvals[];
237 #define ieee754dp_spcvals ((const union ieee754dp *)__ieee754dp_spcvals)
238 #define ieee754sp_spcvals ((const union ieee754sp *)__ieee754sp_spcvals)
239 
240 /*
241  * Return infinity with given sign
242  */
243 #define ieee754dp_inf(sn)     (ieee754dp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
244 #define ieee754dp_zero(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
245 #define ieee754dp_one(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
246 #define ieee754dp_ten(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
247 #define ieee754dp_indef()	(ieee754dp_spcvals[IEEE754_SPCVAL_INDEF_LEG + \
248 						   ieee754_csr.nan2008])
249 #define ieee754dp_max(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
250 #define ieee754dp_min(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
251 #define ieee754dp_mind(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
252 #define ieee754dp_1e31()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E31])
253 #define ieee754dp_1e63()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E63])
254 
255 #define ieee754sp_inf(sn)     (ieee754sp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
256 #define ieee754sp_zero(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
257 #define ieee754sp_one(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
258 #define ieee754sp_ten(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
259 #define ieee754sp_indef()	(ieee754sp_spcvals[IEEE754_SPCVAL_INDEF_LEG + \
260 						   ieee754_csr.nan2008])
261 #define ieee754sp_max(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
262 #define ieee754sp_min(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
263 #define ieee754sp_mind(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
264 #define ieee754sp_1e31()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E31])
265 #define ieee754sp_1e63()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E63])
266 
267 /*
268  * Indefinite integer value
269  */
270 static inline int ieee754si_indef(void)
271 {
272 	return ieee754_csr.nan2008 ? 0 : INT_MAX;
273 }
274 
275 static inline s64 ieee754di_indef(void)
276 {
277 	return ieee754_csr.nan2008 ? 0 : S64_MAX;
278 }
279 
280 /*
281  * Overflow integer value
282  */
283 static inline int ieee754si_overflow(int xs)
284 {
285 	return ieee754_csr.nan2008 && xs ? INT_MIN : INT_MAX;
286 }
287 
288 static inline s64 ieee754di_overflow(int xs)
289 {
290 	return ieee754_csr.nan2008 && xs ? S64_MIN : S64_MAX;
291 }
292 
293 /* result types for xctx.rt */
294 #define IEEE754_RT_SP	0
295 #define IEEE754_RT_DP	1
296 #define IEEE754_RT_XP	2
297 #define IEEE754_RT_SI	3
298 #define IEEE754_RT_DI	4
299 
300 /* compat */
301 #define ieee754dp_fix(x)	ieee754dp_tint(x)
302 #define ieee754sp_fix(x)	ieee754sp_tint(x)
303 
304 #endif /* __ARCH_MIPS_MATH_EMU_IEEE754_H */
305