xref: /linux/arch/mips/math-emu/ieee754.h (revision 63307d015b91e626c97bb82e88054af3d0b74643)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * MIPS floating point support
4  * Copyright (C) 1994-2000 Algorithmics Ltd.
5  *
6  *  Nov 7, 2000
7  *  Modification to allow integration with Linux kernel
8  *
9  *  Kevin D. Kissell, kevink@mips.com and Carsten Langgard, carstenl@mips.com
10  *  Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved.
11  */
12 #ifndef __ARCH_MIPS_MATH_EMU_IEEE754_H
13 #define __ARCH_MIPS_MATH_EMU_IEEE754_H
14 
15 #include <linux/compiler.h>
16 #include <asm/byteorder.h>
17 #include <linux/kernel.h>
18 #include <linux/types.h>
19 #include <linux/sched.h>
20 #include <asm/bitfield.h>
21 
22 union ieee754dp {
23 	struct {
24 		__BITFIELD_FIELD(unsigned int sign:1,
25 		__BITFIELD_FIELD(unsigned int bexp:11,
26 		__BITFIELD_FIELD(u64 mant:52,
27 		;)))
28 	};
29 	u64 bits;
30 };
31 
32 union ieee754sp {
33 	struct {
34 		__BITFIELD_FIELD(unsigned sign:1,
35 		__BITFIELD_FIELD(unsigned bexp:8,
36 		__BITFIELD_FIELD(unsigned mant:23,
37 		;)))
38 	};
39 	u32 bits;
40 };
41 
42 /*
43  * single precision (often aka float)
44 */
45 int ieee754sp_class(union ieee754sp x);
46 
47 union ieee754sp ieee754sp_abs(union ieee754sp x);
48 union ieee754sp ieee754sp_neg(union ieee754sp x);
49 
50 union ieee754sp ieee754sp_add(union ieee754sp x, union ieee754sp y);
51 union ieee754sp ieee754sp_sub(union ieee754sp x, union ieee754sp y);
52 union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y);
53 union ieee754sp ieee754sp_div(union ieee754sp x, union ieee754sp y);
54 
55 union ieee754sp ieee754sp_fint(int x);
56 union ieee754sp ieee754sp_flong(s64 x);
57 union ieee754sp ieee754sp_fdp(union ieee754dp x);
58 union ieee754sp ieee754sp_rint(union ieee754sp x);
59 
60 int ieee754sp_tint(union ieee754sp x);
61 s64 ieee754sp_tlong(union ieee754sp x);
62 
63 int ieee754sp_cmp(union ieee754sp x, union ieee754sp y, int cop, int sig);
64 
65 union ieee754sp ieee754sp_sqrt(union ieee754sp x);
66 
67 union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
68 				union ieee754sp y);
69 union ieee754sp ieee754sp_msubf(union ieee754sp z, union ieee754sp x,
70 				union ieee754sp y);
71 int ieee754sp_2008class(union ieee754sp x);
72 union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y);
73 union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y);
74 union ieee754sp ieee754sp_fmax(union ieee754sp x, union ieee754sp y);
75 union ieee754sp ieee754sp_fmaxa(union ieee754sp x, union ieee754sp y);
76 
77 /*
78  * double precision (often aka double)
79 */
80 int ieee754dp_class(union ieee754dp x);
81 
82 union ieee754dp ieee754dp_add(union ieee754dp x, union ieee754dp y);
83 union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y);
84 union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y);
85 union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y);
86 
87 union ieee754dp ieee754dp_abs(union ieee754dp x);
88 union ieee754dp ieee754dp_neg(union ieee754dp x);
89 
90 union ieee754dp ieee754dp_fint(int x);
91 union ieee754dp ieee754dp_flong(s64 x);
92 union ieee754dp ieee754dp_fsp(union ieee754sp x);
93 union ieee754dp ieee754dp_rint(union ieee754dp 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 union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x,
103 				union ieee754dp y);
104 union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x,
105 				union ieee754dp y);
106 int ieee754dp_2008class(union ieee754dp x);
107 union ieee754dp ieee754dp_fmin(union ieee754dp x, union ieee754dp y);
108 union ieee754dp ieee754dp_fmina(union ieee754dp x, union ieee754dp y);
109 union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y);
110 union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y);
111 
112 
113 /* 5 types of floating point number
114 */
115 enum {
116 	IEEE754_CLASS_NORM	= 0x00,
117 	IEEE754_CLASS_ZERO	= 0x01,
118 	IEEE754_CLASS_DNORM	= 0x02,
119 	IEEE754_CLASS_INF	= 0x03,
120 	IEEE754_CLASS_SNAN	= 0x04,
121 	IEEE754_CLASS_QNAN	= 0x05,
122 };
123 
124 /* exception numbers */
125 #define IEEE754_INEXACT			0x01
126 #define IEEE754_UNDERFLOW		0x02
127 #define IEEE754_OVERFLOW		0x04
128 #define IEEE754_ZERO_DIVIDE		0x08
129 #define IEEE754_INVALID_OPERATION	0x10
130 
131 /* cmp operators
132 */
133 #define IEEE754_CLT	0x01
134 #define IEEE754_CEQ	0x02
135 #define IEEE754_CGT	0x04
136 #define IEEE754_CUN	0x08
137 
138 /*
139  * The control status register
140  */
141 struct _ieee754_csr {
142 	__BITFIELD_FIELD(unsigned fcc:7,	/* condition[7:1] */
143 	__BITFIELD_FIELD(unsigned nod:1,	/* set 1 for no denormals */
144 	__BITFIELD_FIELD(unsigned c:1,		/* condition[0] */
145 	__BITFIELD_FIELD(unsigned pad0:3,
146 	__BITFIELD_FIELD(unsigned abs2008:1,	/* IEEE 754-2008 ABS/NEG.fmt */
147 	__BITFIELD_FIELD(unsigned nan2008:1,	/* IEEE 754-2008 NaN mode */
148 	__BITFIELD_FIELD(unsigned cx:6,		/* exceptions this operation */
149 	__BITFIELD_FIELD(unsigned mx:5,		/* exception enable  mask */
150 	__BITFIELD_FIELD(unsigned sx:5,		/* exceptions total */
151 	__BITFIELD_FIELD(unsigned rm:2,		/* current rounding mode */
152 	;))))))))))
153 };
154 #define ieee754_csr (*(struct _ieee754_csr *)(&current->thread.fpu.fcr31))
155 
156 static inline unsigned int ieee754_getrm(void)
157 {
158 	return (ieee754_csr.rm);
159 }
160 
161 static inline unsigned int ieee754_setrm(unsigned int rm)
162 {
163 	return (ieee754_csr.rm = rm);
164 }
165 
166 /*
167  * get current exceptions
168  */
169 static inline unsigned int ieee754_getcx(void)
170 {
171 	return (ieee754_csr.cx);
172 }
173 
174 /* test for current exception condition
175  */
176 static inline int ieee754_cxtest(unsigned int n)
177 {
178 	return (ieee754_csr.cx & n);
179 }
180 
181 /*
182  * get sticky exceptions
183  */
184 static inline unsigned int ieee754_getsx(void)
185 {
186 	return (ieee754_csr.sx);
187 }
188 
189 /* clear sticky conditions
190 */
191 static inline unsigned int ieee754_clrsx(void)
192 {
193 	return (ieee754_csr.sx = 0);
194 }
195 
196 /* test for sticky exception condition
197  */
198 static inline int ieee754_sxtest(unsigned int n)
199 {
200 	return (ieee754_csr.sx & n);
201 }
202 
203 /* debugging */
204 union ieee754sp ieee754sp_dump(char *s, union ieee754sp x);
205 union ieee754dp ieee754dp_dump(char *s, union ieee754dp x);
206 
207 #define IEEE754_SPCVAL_PZERO		0	/* +0.0 */
208 #define IEEE754_SPCVAL_NZERO		1	/* -0.0 */
209 #define IEEE754_SPCVAL_PONE		2	/* +1.0 */
210 #define IEEE754_SPCVAL_NONE		3	/* -1.0 */
211 #define IEEE754_SPCVAL_PTEN		4	/* +10.0 */
212 #define IEEE754_SPCVAL_NTEN		5	/* -10.0 */
213 #define IEEE754_SPCVAL_PINFINITY	6	/* +inf */
214 #define IEEE754_SPCVAL_NINFINITY	7	/* -inf */
215 #define IEEE754_SPCVAL_INDEF_LEG	8	/* legacy quiet NaN */
216 #define IEEE754_SPCVAL_INDEF_2008	9	/* IEEE 754-2008 quiet NaN */
217 #define IEEE754_SPCVAL_PMAX		10	/* +max norm */
218 #define IEEE754_SPCVAL_NMAX		11	/* -max norm */
219 #define IEEE754_SPCVAL_PMIN		12	/* +min norm */
220 #define IEEE754_SPCVAL_NMIN		13	/* -min norm */
221 #define IEEE754_SPCVAL_PMIND		14	/* +min denorm */
222 #define IEEE754_SPCVAL_NMIND		15	/* -min denorm */
223 #define IEEE754_SPCVAL_P1E31		16	/* + 1.0e31 */
224 #define IEEE754_SPCVAL_P1E63		17	/* + 1.0e63 */
225 
226 extern const union ieee754dp __ieee754dp_spcvals[];
227 extern const union ieee754sp __ieee754sp_spcvals[];
228 #define ieee754dp_spcvals ((const union ieee754dp *)__ieee754dp_spcvals)
229 #define ieee754sp_spcvals ((const union ieee754sp *)__ieee754sp_spcvals)
230 
231 /*
232  * Return infinity with given sign
233  */
234 #define ieee754dp_inf(sn)     (ieee754dp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
235 #define ieee754dp_zero(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
236 #define ieee754dp_one(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
237 #define ieee754dp_ten(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
238 #define ieee754dp_indef()	(ieee754dp_spcvals[IEEE754_SPCVAL_INDEF_LEG + \
239 						   ieee754_csr.nan2008])
240 #define ieee754dp_max(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
241 #define ieee754dp_min(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
242 #define ieee754dp_mind(sn)	(ieee754dp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
243 #define ieee754dp_1e31()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E31])
244 #define ieee754dp_1e63()	(ieee754dp_spcvals[IEEE754_SPCVAL_P1E63])
245 
246 #define ieee754sp_inf(sn)     (ieee754sp_spcvals[IEEE754_SPCVAL_PINFINITY+(sn)])
247 #define ieee754sp_zero(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PZERO+(sn)])
248 #define ieee754sp_one(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PONE+(sn)])
249 #define ieee754sp_ten(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PTEN+(sn)])
250 #define ieee754sp_indef()	(ieee754sp_spcvals[IEEE754_SPCVAL_INDEF_LEG + \
251 						   ieee754_csr.nan2008])
252 #define ieee754sp_max(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMAX+(sn)])
253 #define ieee754sp_min(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIN+(sn)])
254 #define ieee754sp_mind(sn)	(ieee754sp_spcvals[IEEE754_SPCVAL_PMIND+(sn)])
255 #define ieee754sp_1e31()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E31])
256 #define ieee754sp_1e63()	(ieee754sp_spcvals[IEEE754_SPCVAL_P1E63])
257 
258 /*
259  * Indefinite integer value
260  */
261 static inline int ieee754si_indef(void)
262 {
263 	return ieee754_csr.nan2008 ? 0 : INT_MAX;
264 }
265 
266 static inline s64 ieee754di_indef(void)
267 {
268 	return ieee754_csr.nan2008 ? 0 : S64_MAX;
269 }
270 
271 /*
272  * Overflow integer value
273  */
274 static inline int ieee754si_overflow(int xs)
275 {
276 	return ieee754_csr.nan2008 && xs ? INT_MIN : INT_MAX;
277 }
278 
279 static inline s64 ieee754di_overflow(int xs)
280 {
281 	return ieee754_csr.nan2008 && xs ? S64_MIN : S64_MAX;
282 }
283 
284 /* result types for xctx.rt */
285 #define IEEE754_RT_SP	0
286 #define IEEE754_RT_DP	1
287 #define IEEE754_RT_XP	2
288 #define IEEE754_RT_SI	3
289 #define IEEE754_RT_DI	4
290 
291 /* compat */
292 #define ieee754dp_fix(x)	ieee754dp_tint(x)
293 #define ieee754sp_fix(x)	ieee754sp_tint(x)
294 
295 #endif /* __ARCH_MIPS_MATH_EMU_IEEE754_H */
296