xref: /linux/drivers/gpu/drm/amd/display/include/fixed31_32.h (revision 151374fb6e17ce966e1db8e1e2b35ea517202779)
1 /*
2  * Copyright 2012-15 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: AMD
23  *
24  */
25 
26 #ifndef __DAL_FIXED31_32_H__
27 #define __DAL_FIXED31_32_H__
28 
29 #ifndef LLONG_MAX
30 #define LLONG_MAX 9223372036854775807ll
31 #endif
32 #ifndef LLONG_MIN
33 #define LLONG_MIN (-LLONG_MAX - 1ll)
34 #endif
35 
36 #define FIXED31_32_BITS_PER_FRACTIONAL_PART 32
37 #ifndef LLONG_MIN
38 #define LLONG_MIN (1LL<<63)
39 #endif
40 #ifndef LLONG_MAX
41 #define LLONG_MAX (-1LL>>1)
42 #endif
43 
44 /*
45  * @brief
46  * Arithmetic operations on real numbers
47  * represented as fixed-point numbers.
48  * There are: 1 bit for sign,
49  * 31 bit for integer part,
50  * 32 bits for fractional part.
51  *
52  * @note
53  * Currently, overflows and underflows are asserted;
54  * no special result returned.
55  */
56 
57 struct fixed31_32 {
58 	long long value;
59 };
60 
61 
62 /*
63  * @brief
64  * Useful constants
65  */
66 
67 static const struct fixed31_32 dc_fixpt_zero = { 0 };
68 static const struct fixed31_32 dc_fixpt_epsilon = { 1LL };
69 static const struct fixed31_32 dc_fixpt_half = { 0x80000000LL };
70 static const struct fixed31_32 dc_fixpt_one = { 0x100000000LL };
71 
72 static inline struct fixed31_32 dc_fixpt_from_s3132(__u64 x)
73 {
74 	struct fixed31_32 val;
75 
76 	/* If negative, convert to 2's complement. */
77 	if (x & (1ULL << 63))
78 		x = -(x & ~(1ULL << 63));
79 
80 	val.value = x;
81 	return val;
82 }
83 
84 /*
85  * @brief
86  * Initialization routines
87  */
88 
89 /*
90  * @brief
91  * result = numerator / denominator
92  */
93 struct fixed31_32 dc_fixpt_from_fraction(long long numerator, long long denominator);
94 
95 /*
96  * @brief
97  * result = arg
98  */
99 static inline struct fixed31_32 dc_fixpt_from_int(int arg)
100 {
101 	struct fixed31_32 res;
102 
103 	res.value = (long long) arg << FIXED31_32_BITS_PER_FRACTIONAL_PART;
104 
105 	return res;
106 }
107 
108 /*
109  * @brief
110  * Unary operators
111  */
112 
113 /*
114  * @brief
115  * result = -arg
116  */
117 static inline struct fixed31_32 dc_fixpt_neg(struct fixed31_32 arg)
118 {
119 	struct fixed31_32 res;
120 
121 	res.value = -arg.value;
122 
123 	return res;
124 }
125 
126 /*
127  * @brief
128  * result = abs(arg) := (arg >= 0) ? arg : -arg
129  */
130 static inline struct fixed31_32 dc_fixpt_abs(struct fixed31_32 arg)
131 {
132 	if (arg.value < 0)
133 		return dc_fixpt_neg(arg);
134 	else
135 		return arg;
136 }
137 
138 /*
139  * @brief
140  * Binary relational operators
141  */
142 
143 /*
144  * @brief
145  * result = arg1 < arg2
146  */
147 static inline bool dc_fixpt_lt(struct fixed31_32 arg1, struct fixed31_32 arg2)
148 {
149 	return arg1.value < arg2.value;
150 }
151 
152 /*
153  * @brief
154  * result = arg1 <= arg2
155  */
156 static inline bool dc_fixpt_le(struct fixed31_32 arg1, struct fixed31_32 arg2)
157 {
158 	return arg1.value <= arg2.value;
159 }
160 
161 /*
162  * @brief
163  * result = arg1 == arg2
164  */
165 static inline bool dc_fixpt_eq(struct fixed31_32 arg1, struct fixed31_32 arg2)
166 {
167 	return arg1.value == arg2.value;
168 }
169 
170 /*
171  * @brief
172  * result = min(arg1, arg2) := (arg1 <= arg2) ? arg1 : arg2
173  */
174 static inline struct fixed31_32 dc_fixpt_min(struct fixed31_32 arg1, struct fixed31_32 arg2)
175 {
176 	if (arg1.value <= arg2.value)
177 		return arg1;
178 	else
179 		return arg2;
180 }
181 
182 /*
183  * @brief
184  * result = max(arg1, arg2) := (arg1 <= arg2) ? arg2 : arg1
185  */
186 static inline struct fixed31_32 dc_fixpt_max(struct fixed31_32 arg1, struct fixed31_32 arg2)
187 {
188 	if (arg1.value <= arg2.value)
189 		return arg2;
190 	else
191 		return arg1;
192 }
193 
194 /*
195  * @brief
196  *          | min_value, when arg <= min_value
197  * result = | arg, when min_value < arg < max_value
198  *          | max_value, when arg >= max_value
199  */
200 static inline struct fixed31_32 dc_fixpt_clamp(
201 	struct fixed31_32 arg,
202 	struct fixed31_32 min_value,
203 	struct fixed31_32 max_value)
204 {
205 	if (dc_fixpt_le(arg, min_value))
206 		return min_value;
207 	else if (dc_fixpt_le(max_value, arg))
208 		return max_value;
209 	else
210 		return arg;
211 }
212 
213 /*
214  * @brief
215  * Binary shift operators
216  */
217 
218 /*
219  * @brief
220  * result = arg << shift
221  */
222 static inline struct fixed31_32 dc_fixpt_shl(struct fixed31_32 arg, unsigned char shift)
223 {
224 	ASSERT(((arg.value >= 0) && (arg.value <= LLONG_MAX >> shift)) ||
225 		((arg.value < 0) && (arg.value >= ~(LLONG_MAX >> shift))));
226 
227 	arg.value = arg.value << shift;
228 
229 	return arg;
230 }
231 
232 /*
233  * @brief
234  * result = arg >> shift
235  */
236 static inline struct fixed31_32 dc_fixpt_shr(struct fixed31_32 arg, unsigned char shift)
237 {
238 	bool negative = arg.value < 0;
239 
240 	if (negative)
241 		arg.value = -arg.value;
242 	arg.value = arg.value >> shift;
243 	if (negative)
244 		arg.value = -arg.value;
245 	return arg;
246 }
247 
248 /*
249  * @brief
250  * Binary additive operators
251  */
252 
253 /*
254  * @brief
255  * result = arg1 + arg2
256  */
257 static inline struct fixed31_32 dc_fixpt_add(struct fixed31_32 arg1, struct fixed31_32 arg2)
258 {
259 	struct fixed31_32 res;
260 
261 	ASSERT(((arg1.value >= 0) && (LLONG_MAX - arg1.value >= arg2.value)) ||
262 		((arg1.value < 0) && (LLONG_MIN - arg1.value <= arg2.value)));
263 
264 	res.value = arg1.value + arg2.value;
265 
266 	return res;
267 }
268 
269 /*
270  * @brief
271  * result = arg1 + arg2
272  */
273 static inline struct fixed31_32 dc_fixpt_add_int(struct fixed31_32 arg1, int arg2)
274 {
275 	return dc_fixpt_add(arg1, dc_fixpt_from_int(arg2));
276 }
277 
278 /*
279  * @brief
280  * result = arg1 - arg2
281  */
282 static inline struct fixed31_32 dc_fixpt_sub(struct fixed31_32 arg1, struct fixed31_32 arg2)
283 {
284 	struct fixed31_32 res;
285 
286 	ASSERT(((arg2.value >= 0) && (LLONG_MIN + arg2.value <= arg1.value)) ||
287 		((arg2.value < 0) && (LLONG_MAX + arg2.value >= arg1.value)));
288 
289 	res.value = arg1.value - arg2.value;
290 
291 	return res;
292 }
293 
294 /*
295  * @brief
296  * result = arg1 - arg2
297  */
298 static inline struct fixed31_32 dc_fixpt_sub_int(struct fixed31_32 arg1, int arg2)
299 {
300 	return dc_fixpt_sub(arg1, dc_fixpt_from_int(arg2));
301 }
302 
303 
304 /*
305  * @brief
306  * Binary multiplicative operators
307  */
308 
309 /*
310  * @brief
311  * result = arg1 * arg2
312  */
313 struct fixed31_32 dc_fixpt_mul(struct fixed31_32 arg1, struct fixed31_32 arg2);
314 
315 
316 /*
317  * @brief
318  * result = arg1 * arg2
319  */
320 static inline struct fixed31_32 dc_fixpt_mul_int(struct fixed31_32 arg1, int arg2)
321 {
322 	return dc_fixpt_mul(arg1, dc_fixpt_from_int(arg2));
323 }
324 
325 /*
326  * @brief
327  * result = square(arg) := arg * arg
328  */
329 struct fixed31_32 dc_fixpt_sqr(struct fixed31_32 arg);
330 
331 /*
332  * @brief
333  * result = arg1 / arg2
334  */
335 static inline struct fixed31_32 dc_fixpt_div_int(struct fixed31_32 arg1, long long arg2)
336 {
337 	return dc_fixpt_from_fraction(arg1.value, dc_fixpt_from_int((int)arg2).value);
338 }
339 
340 /*
341  * @brief
342  * result = arg1 / arg2
343  */
344 static inline struct fixed31_32 dc_fixpt_div(struct fixed31_32 arg1, struct fixed31_32 arg2)
345 {
346 	return dc_fixpt_from_fraction(arg1.value, arg2.value);
347 }
348 
349 /*
350  * @brief
351  * Reciprocal function
352  */
353 
354 /*
355  * @brief
356  * result = reciprocal(arg) := 1 / arg
357  *
358  * @note
359  * No special actions taken in case argument is zero.
360  */
361 struct fixed31_32 dc_fixpt_recip(struct fixed31_32 arg);
362 
363 /*
364  * @brief
365  * Trigonometric functions
366  */
367 
368 /*
369  * @brief
370  * result = sinc(arg) := sin(arg) / arg
371  *
372  * @note
373  * Argument specified in radians,
374  * internally it's normalized to [-2pi...2pi] range.
375  */
376 struct fixed31_32 dc_fixpt_sinc(struct fixed31_32 arg);
377 
378 /*
379  * @brief
380  * result = sin(arg)
381  *
382  * @note
383  * Argument specified in radians,
384  * internally it's normalized to [-2pi...2pi] range.
385  */
386 struct fixed31_32 dc_fixpt_sin(struct fixed31_32 arg);
387 
388 /*
389  * @brief
390  * result = cos(arg)
391  *
392  * @note
393  * Argument specified in radians
394  * and should be in [-2pi...2pi] range -
395  * passing arguments outside that range
396  * will cause incorrect result!
397  */
398 struct fixed31_32 dc_fixpt_cos(struct fixed31_32 arg);
399 
400 /*
401  * @brief
402  * Transcendent functions
403  */
404 
405 /*
406  * @brief
407  * result = exp(arg)
408  *
409  * @note
410  * Currently, function is verified for abs(arg) <= 1.
411  */
412 struct fixed31_32 dc_fixpt_exp(struct fixed31_32 arg);
413 
414 /*
415  * @brief
416  * result = log(arg)
417  *
418  * @note
419  * Currently, abs(arg) should be less than 1.
420  * No normalization is done.
421  * Currently, no special actions taken
422  * in case of invalid argument(s). Take care!
423  */
424 struct fixed31_32 dc_fixpt_log(struct fixed31_32 arg);
425 
426 /*
427  * @brief
428  * Power function
429  */
430 
431 /*
432  * @brief
433  * result = pow(arg1, arg2)
434  *
435  * @note
436  * Currently, abs(arg1) should be less than 1. Take care!
437  */
438 static inline struct fixed31_32 dc_fixpt_pow(struct fixed31_32 arg1, struct fixed31_32 arg2)
439 {
440 	if (arg1.value == 0)
441 		return arg2.value == 0 ? dc_fixpt_one : dc_fixpt_zero;
442 
443 	return dc_fixpt_exp(
444 		dc_fixpt_mul(
445 			dc_fixpt_log(arg1),
446 			arg2));
447 }
448 
449 /*
450  * @brief
451  * Rounding functions
452  */
453 
454 /*
455  * @brief
456  * result = floor(arg) := greatest integer lower than or equal to arg
457  */
458 static inline int dc_fixpt_floor(struct fixed31_32 arg)
459 {
460 	unsigned long long arg_value = arg.value > 0 ? arg.value : -arg.value;
461 
462 	if (arg.value >= 0)
463 		return (int)(arg_value >> FIXED31_32_BITS_PER_FRACTIONAL_PART);
464 	else
465 		return -(int)(arg_value >> FIXED31_32_BITS_PER_FRACTIONAL_PART);
466 }
467 
468 /*
469  * @brief
470  * result = round(arg) := integer nearest to arg
471  */
472 static inline int dc_fixpt_round(struct fixed31_32 arg)
473 {
474 	unsigned long long arg_value = arg.value > 0 ? arg.value : -arg.value;
475 
476 	const long long summand = dc_fixpt_half.value;
477 
478 	ASSERT(LLONG_MAX - (long long)arg_value >= summand);
479 
480 	arg_value += summand;
481 
482 	if (arg.value >= 0)
483 		return (int)(arg_value >> FIXED31_32_BITS_PER_FRACTIONAL_PART);
484 	else
485 		return -(int)(arg_value >> FIXED31_32_BITS_PER_FRACTIONAL_PART);
486 }
487 
488 /*
489  * @brief
490  * result = ceil(arg) := lowest integer greater than or equal to arg
491  */
492 static inline int dc_fixpt_ceil(struct fixed31_32 arg)
493 {
494 	unsigned long long arg_value = arg.value > 0 ? arg.value : -arg.value;
495 
496 	const long long summand = dc_fixpt_one.value -
497 		dc_fixpt_epsilon.value;
498 
499 	ASSERT(LLONG_MAX - (long long)arg_value >= summand);
500 
501 	arg_value += summand;
502 
503 	if (arg.value >= 0)
504 		return (int)(arg_value >> FIXED31_32_BITS_PER_FRACTIONAL_PART);
505 	else
506 		return -(int)(arg_value >> FIXED31_32_BITS_PER_FRACTIONAL_PART);
507 }
508 
509 /* the following two function are used in scaler hw programming to convert fixed
510  * point value to format 2 bits from integer part and 19 bits from fractional
511  * part. The same applies for u0d19, 0 bits from integer part and 19 bits from
512  * fractional
513  */
514 
515 unsigned int dc_fixpt_u4d19(struct fixed31_32 arg);
516 
517 unsigned int dc_fixpt_u3d19(struct fixed31_32 arg);
518 
519 unsigned int dc_fixpt_u2d19(struct fixed31_32 arg);
520 
521 unsigned int dc_fixpt_u0d19(struct fixed31_32 arg);
522 
523 unsigned int dc_fixpt_clamp_u0d14(struct fixed31_32 arg);
524 
525 unsigned int dc_fixpt_clamp_u0d10(struct fixed31_32 arg);
526 
527 int dc_fixpt_s4d19(struct fixed31_32 arg);
528 
529 static inline struct fixed31_32 dc_fixpt_truncate(struct fixed31_32 arg, unsigned int frac_bits)
530 {
531 	bool negative = arg.value < 0;
532 
533 	if (frac_bits >= FIXED31_32_BITS_PER_FRACTIONAL_PART) {
534 		ASSERT(frac_bits == FIXED31_32_BITS_PER_FRACTIONAL_PART);
535 		return arg;
536 	}
537 
538 	if (negative)
539 		arg.value = -arg.value;
540 	arg.value &= (~0ULL) << (FIXED31_32_BITS_PER_FRACTIONAL_PART - frac_bits);
541 	if (negative)
542 		arg.value = -arg.value;
543 	return arg;
544 }
545 
546 #endif
547