xref: /linux/arch/arm/vfp/vfp.h (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /*
2  *  linux/arch/arm/vfp/vfp.h
3  *
4  *  Copyright (C) 2004 ARM Limited.
5  *  Written by Deep Blue Solutions Limited.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 static inline u32 vfp_shiftright32jamming(u32 val, unsigned int shift)
13 {
14 	if (shift) {
15 		if (shift < 32)
16 			val = val >> shift | ((val << (32 - shift)) != 0);
17 		else
18 			val = val != 0;
19 	}
20 	return val;
21 }
22 
23 static inline u64 vfp_shiftright64jamming(u64 val, unsigned int shift)
24 {
25 	if (shift) {
26 		if (shift < 64)
27 			val = val >> shift | ((val << (64 - shift)) != 0);
28 		else
29 			val = val != 0;
30 	}
31 	return val;
32 }
33 
34 static inline u32 vfp_hi64to32jamming(u64 val)
35 {
36 	u32 v;
37 
38 	asm(
39 	"cmp	%Q1, #1		@ vfp_hi64to32jamming\n\t"
40 	"movcc	%0, %R1\n\t"
41 	"orrcs	%0, %R1, #1"
42 	: "=r" (v) : "r" (val) : "cc");
43 
44 	return v;
45 }
46 
47 static inline void add128(u64 *resh, u64 *resl, u64 nh, u64 nl, u64 mh, u64 ml)
48 {
49 	asm(	"adds	%Q0, %Q2, %Q4\n\t"
50 		"adcs	%R0, %R2, %R4\n\t"
51 		"adcs	%Q1, %Q3, %Q5\n\t"
52 		"adc	%R1, %R3, %R5"
53 	    : "=r" (nl), "=r" (nh)
54 	    : "0" (nl), "1" (nh), "r" (ml), "r" (mh)
55 	    : "cc");
56 	*resh = nh;
57 	*resl = nl;
58 }
59 
60 static inline void sub128(u64 *resh, u64 *resl, u64 nh, u64 nl, u64 mh, u64 ml)
61 {
62 	asm(	"subs	%Q0, %Q2, %Q4\n\t"
63 		"sbcs	%R0, %R2, %R4\n\t"
64 		"sbcs	%Q1, %Q3, %Q5\n\t"
65 		"sbc	%R1, %R3, %R5\n\t"
66 	    : "=r" (nl), "=r" (nh)
67 	    : "0" (nl), "1" (nh), "r" (ml), "r" (mh)
68 	    : "cc");
69 	*resh = nh;
70 	*resl = nl;
71 }
72 
73 static inline void mul64to128(u64 *resh, u64 *resl, u64 n, u64 m)
74 {
75 	u32 nh, nl, mh, ml;
76 	u64 rh, rma, rmb, rl;
77 
78 	nl = n;
79 	ml = m;
80 	rl = (u64)nl * ml;
81 
82 	nh = n >> 32;
83 	rma = (u64)nh * ml;
84 
85 	mh = m >> 32;
86 	rmb = (u64)nl * mh;
87 	rma += rmb;
88 
89 	rh = (u64)nh * mh;
90 	rh += ((u64)(rma < rmb) << 32) + (rma >> 32);
91 
92 	rma <<= 32;
93 	rl += rma;
94 	rh += (rl < rma);
95 
96 	*resl = rl;
97 	*resh = rh;
98 }
99 
100 static inline void shift64left(u64 *resh, u64 *resl, u64 n)
101 {
102 	*resh = n >> 63;
103 	*resl = n << 1;
104 }
105 
106 static inline u64 vfp_hi64multiply64(u64 n, u64 m)
107 {
108 	u64 rh, rl;
109 	mul64to128(&rh, &rl, n, m);
110 	return rh | (rl != 0);
111 }
112 
113 static inline u64 vfp_estimate_div128to64(u64 nh, u64 nl, u64 m)
114 {
115 	u64 mh, ml, remh, reml, termh, terml, z;
116 
117 	if (nh >= m)
118 		return ~0ULL;
119 	mh = m >> 32;
120 	if (mh << 32 <= nh) {
121 		z = 0xffffffff00000000ULL;
122 	} else {
123 		z = nh;
124 		do_div(z, mh);
125 		z <<= 32;
126 	}
127 	mul64to128(&termh, &terml, m, z);
128 	sub128(&remh, &reml, nh, nl, termh, terml);
129 	ml = m << 32;
130 	while ((s64)remh < 0) {
131 		z -= 0x100000000ULL;
132 		add128(&remh, &reml, remh, reml, mh, ml);
133 	}
134 	remh = (remh << 32) | (reml >> 32);
135 	if (mh << 32 <= remh) {
136 		z |= 0xffffffff;
137 	} else {
138 		do_div(remh, mh);
139 		z |= remh;
140 	}
141 	return z;
142 }
143 
144 /*
145  * Operations on unpacked elements
146  */
147 #define vfp_sign_negate(sign)	(sign ^ 0x8000)
148 
149 /*
150  * Single-precision
151  */
152 struct vfp_single {
153 	s16	exponent;
154 	u16	sign;
155 	u32	significand;
156 };
157 
158 extern s32 vfp_get_float(unsigned int reg);
159 extern void vfp_put_float(s32 val, unsigned int reg);
160 
161 /*
162  * VFP_SINGLE_MANTISSA_BITS - number of bits in the mantissa
163  * VFP_SINGLE_EXPONENT_BITS - number of bits in the exponent
164  * VFP_SINGLE_LOW_BITS - number of low bits in the unpacked significand
165  *  which are not propagated to the float upon packing.
166  */
167 #define VFP_SINGLE_MANTISSA_BITS	(23)
168 #define VFP_SINGLE_EXPONENT_BITS	(8)
169 #define VFP_SINGLE_LOW_BITS		(32 - VFP_SINGLE_MANTISSA_BITS - 2)
170 #define VFP_SINGLE_LOW_BITS_MASK	((1 << VFP_SINGLE_LOW_BITS) - 1)
171 
172 /*
173  * The bit in an unpacked float which indicates that it is a quiet NaN
174  */
175 #define VFP_SINGLE_SIGNIFICAND_QNAN	(1 << (VFP_SINGLE_MANTISSA_BITS - 1 + VFP_SINGLE_LOW_BITS))
176 
177 /*
178  * Operations on packed single-precision numbers
179  */
180 #define vfp_single_packed_sign(v)	((v) & 0x80000000)
181 #define vfp_single_packed_negate(v)	((v) ^ 0x80000000)
182 #define vfp_single_packed_abs(v)	((v) & ~0x80000000)
183 #define vfp_single_packed_exponent(v)	(((v) >> VFP_SINGLE_MANTISSA_BITS) & ((1 << VFP_SINGLE_EXPONENT_BITS) - 1))
184 #define vfp_single_packed_mantissa(v)	((v) & ((1 << VFP_SINGLE_MANTISSA_BITS) - 1))
185 
186 /*
187  * Unpack a single-precision float.  Note that this returns the magnitude
188  * of the single-precision float mantissa with the 1. if necessary,
189  * aligned to bit 30.
190  */
191 static inline void vfp_single_unpack(struct vfp_single *s, s32 val)
192 {
193 	u32 significand;
194 
195 	s->sign = vfp_single_packed_sign(val) >> 16,
196 	s->exponent = vfp_single_packed_exponent(val);
197 
198 	significand = (u32) val;
199 	significand = (significand << (32 - VFP_SINGLE_MANTISSA_BITS)) >> 2;
200 	if (s->exponent && s->exponent != 255)
201 		significand |= 0x40000000;
202 	s->significand = significand;
203 }
204 
205 /*
206  * Re-pack a single-precision float.  This assumes that the float is
207  * already normalised such that the MSB is bit 30, _not_ bit 31.
208  */
209 static inline s32 vfp_single_pack(struct vfp_single *s)
210 {
211 	u32 val;
212 	val = (s->sign << 16) +
213 	      (s->exponent << VFP_SINGLE_MANTISSA_BITS) +
214 	      (s->significand >> VFP_SINGLE_LOW_BITS);
215 	return (s32)val;
216 }
217 
218 #define VFP_NUMBER		(1<<0)
219 #define VFP_ZERO		(1<<1)
220 #define VFP_DENORMAL		(1<<2)
221 #define VFP_INFINITY		(1<<3)
222 #define VFP_NAN			(1<<4)
223 #define VFP_NAN_SIGNAL		(1<<5)
224 
225 #define VFP_QNAN		(VFP_NAN)
226 #define VFP_SNAN		(VFP_NAN|VFP_NAN_SIGNAL)
227 
228 static inline int vfp_single_type(struct vfp_single *s)
229 {
230 	int type = VFP_NUMBER;
231 	if (s->exponent == 255) {
232 		if (s->significand == 0)
233 			type = VFP_INFINITY;
234 		else if (s->significand & VFP_SINGLE_SIGNIFICAND_QNAN)
235 			type = VFP_QNAN;
236 		else
237 			type = VFP_SNAN;
238 	} else if (s->exponent == 0) {
239 		if (s->significand == 0)
240 			type |= VFP_ZERO;
241 		else
242 			type |= VFP_DENORMAL;
243 	}
244 	return type;
245 }
246 
247 #ifndef DEBUG
248 #define vfp_single_normaliseround(sd,vsd,fpscr,except,func) __vfp_single_normaliseround(sd,vsd,fpscr,except)
249 u32 __vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions);
250 #else
251 u32 vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions, const char *func);
252 #endif
253 
254 /*
255  * Double-precision
256  */
257 struct vfp_double {
258 	s16	exponent;
259 	u16	sign;
260 	u64	significand;
261 };
262 
263 /*
264  * VFP_REG_ZERO is a special register number for vfp_get_double
265  * which returns (double)0.0.  This is useful for the compare with
266  * zero instructions.
267  */
268 #ifdef CONFIG_VFPv3
269 #define VFP_REG_ZERO	32
270 #else
271 #define VFP_REG_ZERO	16
272 #endif
273 extern u64 vfp_get_double(unsigned int reg);
274 extern void vfp_put_double(u64 val, unsigned int reg);
275 
276 #define VFP_DOUBLE_MANTISSA_BITS	(52)
277 #define VFP_DOUBLE_EXPONENT_BITS	(11)
278 #define VFP_DOUBLE_LOW_BITS		(64 - VFP_DOUBLE_MANTISSA_BITS - 2)
279 #define VFP_DOUBLE_LOW_BITS_MASK	((1 << VFP_DOUBLE_LOW_BITS) - 1)
280 
281 /*
282  * The bit in an unpacked double which indicates that it is a quiet NaN
283  */
284 #define VFP_DOUBLE_SIGNIFICAND_QNAN	(1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1 + VFP_DOUBLE_LOW_BITS))
285 
286 /*
287  * Operations on packed single-precision numbers
288  */
289 #define vfp_double_packed_sign(v)	((v) & (1ULL << 63))
290 #define vfp_double_packed_negate(v)	((v) ^ (1ULL << 63))
291 #define vfp_double_packed_abs(v)	((v) & ~(1ULL << 63))
292 #define vfp_double_packed_exponent(v)	(((v) >> VFP_DOUBLE_MANTISSA_BITS) & ((1 << VFP_DOUBLE_EXPONENT_BITS) - 1))
293 #define vfp_double_packed_mantissa(v)	((v) & ((1ULL << VFP_DOUBLE_MANTISSA_BITS) - 1))
294 
295 /*
296  * Unpack a double-precision float.  Note that this returns the magnitude
297  * of the double-precision float mantissa with the 1. if necessary,
298  * aligned to bit 62.
299  */
300 static inline void vfp_double_unpack(struct vfp_double *s, s64 val)
301 {
302 	u64 significand;
303 
304 	s->sign = vfp_double_packed_sign(val) >> 48;
305 	s->exponent = vfp_double_packed_exponent(val);
306 
307 	significand = (u64) val;
308 	significand = (significand << (64 - VFP_DOUBLE_MANTISSA_BITS)) >> 2;
309 	if (s->exponent && s->exponent != 2047)
310 		significand |= (1ULL << 62);
311 	s->significand = significand;
312 }
313 
314 /*
315  * Re-pack a double-precision float.  This assumes that the float is
316  * already normalised such that the MSB is bit 30, _not_ bit 31.
317  */
318 static inline s64 vfp_double_pack(struct vfp_double *s)
319 {
320 	u64 val;
321 	val = ((u64)s->sign << 48) +
322 	      ((u64)s->exponent << VFP_DOUBLE_MANTISSA_BITS) +
323 	      (s->significand >> VFP_DOUBLE_LOW_BITS);
324 	return (s64)val;
325 }
326 
327 static inline int vfp_double_type(struct vfp_double *s)
328 {
329 	int type = VFP_NUMBER;
330 	if (s->exponent == 2047) {
331 		if (s->significand == 0)
332 			type = VFP_INFINITY;
333 		else if (s->significand & VFP_DOUBLE_SIGNIFICAND_QNAN)
334 			type = VFP_QNAN;
335 		else
336 			type = VFP_SNAN;
337 	} else if (s->exponent == 0) {
338 		if (s->significand == 0)
339 			type |= VFP_ZERO;
340 		else
341 			type |= VFP_DENORMAL;
342 	}
343 	return type;
344 }
345 
346 u32 vfp_double_normaliseround(int dd, struct vfp_double *vd, u32 fpscr, u32 exceptions, const char *func);
347 
348 u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand);
349 
350 /*
351  * A special flag to tell the normalisation code not to normalise.
352  */
353 #define VFP_NAN_FLAG	0x100
354 
355 /*
356  * A bit pattern used to indicate the initial (unset) value of the
357  * exception mask, in case nothing handles an instruction.  This
358  * doesn't include the NAN flag, which get masked out before
359  * we check for an error.
360  */
361 #define VFP_EXCEPTION_ERROR	((u32)-1 & ~VFP_NAN_FLAG)
362 
363 /*
364  * A flag to tell vfp instruction type.
365  *  OP_SCALAR - this operation always operates in scalar mode
366  *  OP_SD - the instruction exceptionally writes to a single precision result.
367  *  OP_DD - the instruction exceptionally writes to a double precision result.
368  *  OP_SM - the instruction exceptionally reads from a single precision operand.
369  */
370 #define OP_SCALAR	(1 << 0)
371 #define OP_SD		(1 << 1)
372 #define OP_DD		(1 << 1)
373 #define OP_SM		(1 << 2)
374 
375 struct op {
376 	u32 (* const fn)(int dd, int dn, int dm, u32 fpscr);
377 	u32 flags;
378 };
379 
380 extern void vfp_save_state(void *location, u32 fpexc);
381