1 /**************************************************************************
2 *
3 * Copyright 2008 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29 /**
30 * Math utilities and approximations for common math functions.
31 * Reduced precision is usually acceptable in shaders...
32 *
33 * "fast" is used in the names of functions which are low-precision,
34 * or at least lower-precision than the normal C lib functions.
35 */
36
37
38 #ifndef U_MATH_H
39 #define U_MATH_H
40
41
42 #include "c99_compat.h"
43 #include <assert.h>
44 #include <float.h>
45 #include <stdarg.h>
46 #include <math.h>
47
48 #include "bitscan.h"
49 #include "u_endian.h" /* for UTIL_ARCH_BIG_ENDIAN */
50 #include "util/detect_cc.h"
51 #include "util/detect_arch.h"
52 #include "util/macros.h"
53
54 #ifdef __HAIKU__
55 #include <sys/param.h>
56 #undef ALIGN
57 #endif
58
59 #ifdef __cplusplus
60 extern "C" {
61 #endif
62
63
64 #ifndef M_SQRT2
65 #define M_SQRT2 1.41421356237309504880
66 #endif
67
68
69 /**
70 * Initialize math module. This should be called before using any
71 * other functions in this module.
72 */
73 extern void
74 util_init_math(void);
75
76
77 union fi {
78 float f;
79 int32_t i;
80 uint32_t ui;
81 };
82
83
84 union di {
85 double d;
86 int64_t i;
87 uint64_t ui;
88 };
89
90
91 /**
92 * Extract the IEEE float32 exponent.
93 */
94 static inline signed
util_get_float32_exponent(float x)95 util_get_float32_exponent(float x)
96 {
97 union fi f;
98
99 f.f = x;
100
101 return ((f.ui >> 23) & 0xff) - 127;
102 }
103
104
105 #define LOG2_TABLE_SIZE_LOG2 8
106 #define LOG2_TABLE_SCALE (1 << LOG2_TABLE_SIZE_LOG2)
107 #define LOG2_TABLE_SIZE (LOG2_TABLE_SCALE + 1)
108 extern float log2_table[LOG2_TABLE_SIZE];
109
110
111 /**
112 * Fast approximation to log2(x).
113 */
114 static inline float
util_fast_log2(float x)115 util_fast_log2(float x)
116 {
117 union fi num;
118 float epart, mpart;
119 num.f = x;
120 epart = (float)(((num.i & 0x7f800000) >> 23) - 127);
121 /* mpart = log2_table[mantissa*LOG2_TABLE_SCALE + 0.5] */
122 mpart = log2_table[((num.i & 0x007fffff) + (1 << (22 - LOG2_TABLE_SIZE_LOG2))) >> (23 - LOG2_TABLE_SIZE_LOG2)];
123 return epart + mpart;
124 }
125
126
127 /**
128 * Floor(x), returned as int.
129 */
130 static inline int
util_ifloor(float f)131 util_ifloor(float f)
132 {
133 #if defined(USE_X86_ASM) && defined(__GNUC__) && defined(__i386__)
134 /*
135 * IEEE floor for computers that round to nearest or even.
136 * 'f' must be between -4194304 and 4194303.
137 * This floor operation is done by "(iround(f + .5) + iround(f - .5)) >> 1",
138 * but uses some IEEE specific tricks for better speed.
139 * Contributed by Josh Vanderhoof
140 */
141 int ai, bi;
142 double af, bf;
143 af = (3 << 22) + 0.5 + (double)f;
144 bf = (3 << 22) + 0.5 - (double)f;
145 /* GCC generates an extra fstp/fld without this. */
146 __asm__ ("fstps %0" : "=m" (ai) : "t" (af) : "st");
147 __asm__ ("fstps %0" : "=m" (bi) : "t" (bf) : "st");
148 return (ai - bi) >> 1;
149 #else
150 int ai, bi;
151 double af, bf;
152 union fi u;
153 af = (3 << 22) + 0.5 + (double) f;
154 bf = (3 << 22) + 0.5 - (double) f;
155 u.f = (float) af; ai = u.i;
156 u.f = (float) bf; bi = u.i;
157 return (ai - bi) >> 1;
158 #endif
159 }
160
161
162 /**
163 * Round float to nearest int.
164 * the range of f should be [INT_MIN, INT_MAX]
165 */
166 static inline int
util_iround(float f)167 util_iround(float f)
168 {
169 return (int)lrintf(f);
170 }
171
172
173 /**
174 * Approximate floating point comparison
175 */
176 static inline bool
util_is_approx(float a,float b,float tol)177 util_is_approx(float a, float b, float tol)
178 {
179 return fabsf(b - a) <= tol;
180 }
181
182
183 /**
184 * util_is_X_inf_or_nan = test if x is NaN or +/- Inf
185 * util_is_X_nan = test if x is NaN
186 * util_X_inf_sign = return +1 for +Inf, -1 for -Inf, or 0 for not Inf
187 *
188 * NaN can be checked with x != x, however this fails with the fast math flag
189 **/
190
191
192 /**
193 * Single-float
194 */
195 static inline bool
util_is_inf_or_nan(float x)196 util_is_inf_or_nan(float x)
197 {
198 union fi tmp;
199 tmp.f = x;
200 return (tmp.ui & 0x7f800000) == 0x7f800000;
201 }
202
203
204 static inline bool
util_is_nan(float x)205 util_is_nan(float x)
206 {
207 union fi tmp;
208 tmp.f = x;
209 return (tmp.ui & 0x7fffffff) > 0x7f800000;
210 }
211
212
213 static inline int
util_inf_sign(float x)214 util_inf_sign(float x)
215 {
216 union fi tmp;
217 tmp.f = x;
218 if ((tmp.ui & 0x7fffffff) != 0x7f800000) {
219 return 0;
220 }
221
222 return (x < 0) ? -1 : 1;
223 }
224
225
226 /**
227 * Double-float
228 */
229 static inline bool
util_is_double_inf_or_nan(double x)230 util_is_double_inf_or_nan(double x)
231 {
232 union di tmp;
233 tmp.d = x;
234 return (tmp.ui & 0x7ff0000000000000ULL) == 0x7ff0000000000000ULL;
235 }
236
237
238 static inline bool
util_is_double_nan(double x)239 util_is_double_nan(double x)
240 {
241 union di tmp;
242 tmp.d = x;
243 return (tmp.ui & 0x7fffffffffffffffULL) > 0x7ff0000000000000ULL;
244 }
245
246
247 static inline int
util_double_inf_sign(double x)248 util_double_inf_sign(double x)
249 {
250 union di tmp;
251 tmp.d = x;
252 if ((tmp.ui & 0x7fffffffffffffffULL) != 0x7ff0000000000000ULL) {
253 return 0;
254 }
255
256 return (x < 0) ? -1 : 1;
257 }
258
259
260 /**
261 * Half-float
262 */
263 static inline bool
util_is_half_inf_or_nan(int16_t x)264 util_is_half_inf_or_nan(int16_t x)
265 {
266 return (x & 0x7c00) == 0x7c00;
267 }
268
269
270 static inline bool
util_is_half_nan(int16_t x)271 util_is_half_nan(int16_t x)
272 {
273 return (x & 0x7fff) > 0x7c00;
274 }
275
276
277 static inline int
util_half_inf_sign(int16_t x)278 util_half_inf_sign(int16_t x)
279 {
280 if ((x & 0x7fff) != 0x7c00) {
281 return 0;
282 }
283
284 return (x < 0) ? -1 : 1;
285 }
286
287
288 /**
289 * Return float bits.
290 */
291 static inline unsigned
fui(float f)292 fui( float f )
293 {
294 union fi fi;
295 fi.f = f;
296 return fi.ui;
297 }
298
299 static inline float
uif(uint32_t ui)300 uif(uint32_t ui)
301 {
302 union fi fi;
303 fi.ui = ui;
304 return fi.f;
305 }
306
307
308 /**
309 * Convert uint8_t to float in [0, 1].
310 */
311 static inline float
ubyte_to_float(uint8_t ub)312 ubyte_to_float(uint8_t ub)
313 {
314 return (float) ub * (1.0f / 255.0f);
315 }
316
317
318 /**
319 * Convert float in [0,1] to uint8_t in [0,255] with clamping.
320 */
321 static inline uint8_t
float_to_ubyte(float f)322 float_to_ubyte(float f)
323 {
324 /* return 0 for NaN too */
325 if (!(f > 0.0f)) {
326 return (uint8_t) 0;
327 }
328 else if (f >= 1.0f) {
329 return (uint8_t) 255;
330 }
331 else {
332 union fi tmp;
333 tmp.f = f;
334 tmp.f = tmp.f * (255.0f/256.0f) + 32768.0f;
335 return (uint8_t) tmp.i;
336 }
337 }
338
339 /**
340 * Convert uint16_t to float in [0, 1].
341 */
342 static inline float
ushort_to_float(uint16_t us)343 ushort_to_float(uint16_t us)
344 {
345 return (float) us * (1.0f / 65535.0f);
346 }
347
348
349 /**
350 * Convert float in [0,1] to uint16_t in [0,65535] with clamping.
351 */
352 static inline uint16_t
float_to_ushort(float f)353 float_to_ushort(float f)
354 {
355 /* return 0 for NaN too */
356 if (!(f > 0.0f)) {
357 return (uint16_t) 0;
358 }
359 else if (f >= 1.0f) {
360 return (uint16_t) 65535;
361 }
362 else {
363 union fi tmp;
364 tmp.f = f;
365 tmp.f = tmp.f * (65535.0f/65536.0f) + 128.0f;
366 return (uint16_t) tmp.i;
367 }
368 }
369
370 static inline float
byte_to_float_tex(int8_t b)371 byte_to_float_tex(int8_t b)
372 {
373 return (b == -128) ? -1.0F : b * 1.0F / 127.0F;
374 }
375
376 static inline int8_t
float_to_byte_tex(float f)377 float_to_byte_tex(float f)
378 {
379 return (int8_t) (127.0F * f);
380 }
381
382 /**
383 * Calc log base 2
384 */
385 static inline unsigned
util_logbase2(unsigned n)386 util_logbase2(unsigned n)
387 {
388 #if defined(HAVE___BUILTIN_CLZ)
389 return ((sizeof(unsigned) * 8 - 1) - __builtin_clz(n | 1));
390 #else
391 unsigned pos = 0;
392 if (n >= 1<<16) { n >>= 16; pos += 16; }
393 if (n >= 1<< 8) { n >>= 8; pos += 8; }
394 if (n >= 1<< 4) { n >>= 4; pos += 4; }
395 if (n >= 1<< 2) { n >>= 2; pos += 2; }
396 if (n >= 1<< 1) { pos += 1; }
397 return pos;
398 #endif
399 }
400
401 static inline uint64_t
util_logbase2_64(uint64_t n)402 util_logbase2_64(uint64_t n)
403 {
404 #if defined(HAVE___BUILTIN_CLZLL)
405 return ((sizeof(uint64_t) * 8 - 1) - __builtin_clzll(n | 1));
406 #else
407 uint64_t pos = 0ull;
408 if (n >= 1ull<<32) { n >>= 32; pos += 32; }
409 if (n >= 1ull<<16) { n >>= 16; pos += 16; }
410 if (n >= 1ull<< 8) { n >>= 8; pos += 8; }
411 if (n >= 1ull<< 4) { n >>= 4; pos += 4; }
412 if (n >= 1ull<< 2) { n >>= 2; pos += 2; }
413 if (n >= 1ull<< 1) { pos += 1; }
414 return pos;
415 #endif
416 }
417
418 /**
419 * Returns the ceiling of log n base 2, and 0 when n == 0. Equivalently,
420 * returns the smallest x such that n <= 2**x.
421 */
422 static inline unsigned
util_logbase2_ceil(unsigned n)423 util_logbase2_ceil(unsigned n)
424 {
425 if (n <= 1)
426 return 0;
427
428 return 1 + util_logbase2(n - 1);
429 }
430
431 static inline uint64_t
util_logbase2_ceil64(uint64_t n)432 util_logbase2_ceil64(uint64_t n)
433 {
434 if (n <= 1)
435 return 0;
436
437 return 1ull + util_logbase2_64(n - 1);
438 }
439
440 /**
441 * Returns the smallest power of two >= x
442 */
443 static inline unsigned
util_next_power_of_two(unsigned x)444 util_next_power_of_two(unsigned x)
445 {
446 #if defined(HAVE___BUILTIN_CLZ)
447 if (x <= 1)
448 return 1;
449
450 return (1 << ((sizeof(unsigned) * 8) - __builtin_clz(x - 1)));
451 #else
452 unsigned val = x;
453
454 if (x <= 1)
455 return 1;
456
457 if (util_is_power_of_two_or_zero(x))
458 return x;
459
460 val--;
461 val = (val >> 1) | val;
462 val = (val >> 2) | val;
463 val = (val >> 4) | val;
464 val = (val >> 8) | val;
465 val = (val >> 16) | val;
466 val++;
467 return val;
468 #endif
469 }
470
471 static inline uint64_t
util_next_power_of_two64(uint64_t x)472 util_next_power_of_two64(uint64_t x)
473 {
474 #if defined(HAVE___BUILTIN_CLZLL)
475 if (x <= 1)
476 return 1;
477
478 return (1ull << ((sizeof(uint64_t) * 8) - __builtin_clzll(x - 1)));
479 #else
480 uint64_t val = x;
481
482 if (x <= 1)
483 return 1;
484
485 if (util_is_power_of_two_or_zero64(x))
486 return x;
487
488 val--;
489 val = (val >> 1) | val;
490 val = (val >> 2) | val;
491 val = (val >> 4) | val;
492 val = (val >> 8) | val;
493 val = (val >> 16) | val;
494 val = (val >> 32) | val;
495 val++;
496 return val;
497 #endif
498 }
499
500 /**
501 * Reverse bits in n
502 * Algorithm taken from:
503 * http://stackoverflow.com/questions/9144800/c-reverse-bits-in-unsigned-integer
504 */
505 static inline unsigned
util_bitreverse(unsigned n)506 util_bitreverse(unsigned n)
507 {
508 n = ((n >> 1) & 0x55555555u) | ((n & 0x55555555u) << 1);
509 n = ((n >> 2) & 0x33333333u) | ((n & 0x33333333u) << 2);
510 n = ((n >> 4) & 0x0f0f0f0fu) | ((n & 0x0f0f0f0fu) << 4);
511 n = ((n >> 8) & 0x00ff00ffu) | ((n & 0x00ff00ffu) << 8);
512 n = ((n >> 16) & 0xffffu) | ((n & 0xffffu) << 16);
513 return n;
514 }
515
516 /**
517 * Convert from little endian to CPU byte order.
518 */
519
520 #if UTIL_ARCH_BIG_ENDIAN
521 #define util_le64_to_cpu(x) util_bswap64(x)
522 #define util_le32_to_cpu(x) util_bswap32(x)
523 #define util_le16_to_cpu(x) util_bswap16(x)
524 #else
525 #define util_le64_to_cpu(x) (x)
526 #define util_le32_to_cpu(x) (x)
527 #define util_le16_to_cpu(x) (x)
528 #endif
529
530 #define util_cpu_to_le64(x) util_le64_to_cpu(x)
531 #define util_cpu_to_le32(x) util_le32_to_cpu(x)
532 #define util_cpu_to_le16(x) util_le16_to_cpu(x)
533
534 /**
535 * Reverse byte order of a 32 bit word.
536 */
537 static inline uint32_t
util_bswap32(uint32_t n)538 util_bswap32(uint32_t n)
539 {
540 #if defined(HAVE___BUILTIN_BSWAP32)
541 return __builtin_bswap32(n);
542 #else
543 return (n >> 24) |
544 ((n >> 8) & 0x0000ff00) |
545 ((n << 8) & 0x00ff0000) |
546 (n << 24);
547 #endif
548 }
549
550 /**
551 * Reverse byte order of a 64bit word.
552 */
553 static inline uint64_t
util_bswap64(uint64_t n)554 util_bswap64(uint64_t n)
555 {
556 #if defined(HAVE___BUILTIN_BSWAP64)
557 return __builtin_bswap64(n);
558 #else
559 return ((uint64_t)util_bswap32((uint32_t)n) << 32) |
560 util_bswap32((n >> 32));
561 #endif
562 }
563
564
565 /**
566 * Reverse byte order of a 16 bit word.
567 */
568 static inline uint16_t
util_bswap16(uint16_t n)569 util_bswap16(uint16_t n)
570 {
571 return (n >> 8) |
572 (n << 8);
573 }
574
575 /**
576 * Mask and sign-extend a number
577 *
578 * The bit at position `width - 1` is replicated to all the higher bits.
579 * This makes no assumptions about the high bits of the value and will
580 * overwrite them with the sign bit.
581 */
582 static inline int64_t
util_mask_sign_extend(uint64_t val,unsigned width)583 util_mask_sign_extend(uint64_t val, unsigned width)
584 {
585 assert(width > 0 && width <= 64);
586 unsigned shift = 64 - width;
587 return (int64_t)(val << shift) >> shift;
588 }
589
590 /**
591 * Sign-extend a number
592 *
593 * The bit at position `width - 1` is replicated to all the higher bits.
594 * This assumes and asserts that the value fits into `width` bits.
595 */
596 static inline int64_t
util_sign_extend(uint64_t val,unsigned width)597 util_sign_extend(uint64_t val, unsigned width)
598 {
599 assert(width == 64 || val < (UINT64_C(1) << width));
600 return util_mask_sign_extend(val, width);
601 }
602
603 static inline void*
util_memcpy_cpu_to_le32(void * restrict dest,const void * restrict src,size_t n)604 util_memcpy_cpu_to_le32(void * restrict dest, const void * restrict src, size_t n)
605 {
606 #if UTIL_ARCH_BIG_ENDIAN
607 size_t i, e;
608 assert(n % 4 == 0);
609
610 for (i = 0, e = n / 4; i < e; i++) {
611 uint32_t * restrict d = (uint32_t* restrict)dest;
612 const uint32_t * restrict s = (const uint32_t* restrict)src;
613 d[i] = util_bswap32(s[i]);
614 }
615 return dest;
616 #else
617 return memcpy(dest, src, n);
618 #endif
619 }
620
621 /**
622 * Clamp X to [MIN, MAX].
623 * This is a macro to allow float, int, uint, etc. types.
624 * We arbitrarily turn NaN into MIN.
625 */
626 #define CLAMP( X, MIN, MAX ) ( (X)>(MIN) ? ((X)>(MAX) ? (MAX) : (X)) : (MIN) )
627
628 /* Syntax sugar occuring frequently in graphics code */
629 #define SATURATE( X ) CLAMP(X, 0.0f, 1.0f)
630
631 #define MIN2( A, B ) ( (A)<(B) ? (A) : (B) )
632 #define MAX2( A, B ) ( (A)>(B) ? (A) : (B) )
633
634 #define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
635 #define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
636
637 #define MIN4( A, B, C, D ) ((A) < (B) ? MIN3(A, C, D) : MIN3(B, C, D))
638 #define MAX4( A, B, C, D ) ((A) > (B) ? MAX3(A, C, D) : MAX3(B, C, D))
639
640
641 /**
642 * Align a value up to an alignment value
643 *
644 * If \c value is not already aligned to the requested alignment value, it
645 * will be rounded up.
646 *
647 * \param value Value to be rounded
648 * \param alignment Alignment value to be used. This must be a power of two.
649 *
650 * \sa ROUND_DOWN_TO()
651 */
652
653 #if defined(ALIGN)
654 #undef ALIGN
655 #endif
656 static inline uintptr_t
ALIGN(uintptr_t value,int32_t alignment)657 ALIGN(uintptr_t value, int32_t alignment)
658 {
659 assert(util_is_power_of_two_nonzero(alignment));
660 return ALIGN_POT(value, alignment);
661 }
662
663 /**
664 * Like ALIGN(), but works with a non-power-of-two alignment.
665 */
666 static inline uintptr_t
ALIGN_NPOT(uintptr_t value,int32_t alignment)667 ALIGN_NPOT(uintptr_t value, int32_t alignment)
668 {
669 assert(alignment > 0);
670 return (value + alignment - 1) / alignment * alignment;
671 }
672
673 /**
674 * Align a value down to an alignment value
675 *
676 * If \c value is not already aligned to the requested alignment value, it
677 * will be rounded down.
678 *
679 * \param value Value to be rounded
680 * \param alignment Alignment value to be used. This must be a power of two.
681 *
682 * \sa ALIGN()
683 */
684 static inline uint64_t
ROUND_DOWN_TO(uint64_t value,uint32_t alignment)685 ROUND_DOWN_TO(uint64_t value, uint32_t alignment)
686 {
687 assert(util_is_power_of_two_nonzero(alignment));
688 return ((value) & ~(uint64_t)(alignment - 1));
689 }
690
691 /**
692 * Align a value, only works pot alignemnts.
693 */
694 static inline uint32_t
align(uint32_t value,uint32_t alignment)695 align(uint32_t value, uint32_t alignment)
696 {
697 assert(util_is_power_of_two_nonzero(alignment));
698 return ALIGN_POT(value, alignment);
699 }
700
701 static inline uint64_t
align64(uint64_t value,uint64_t alignment)702 align64(uint64_t value, uint64_t alignment)
703 {
704 assert(util_is_power_of_two_nonzero64(alignment));
705 return ALIGN_POT(value, alignment);
706 }
707
708 /**
709 * Works like align but on npot alignments.
710 */
711 static inline size_t
util_align_npot(size_t value,size_t alignment)712 util_align_npot(size_t value, size_t alignment)
713 {
714 if (value % alignment)
715 return value + (alignment - (value % alignment));
716 return value;
717 }
718
719 static inline unsigned
u_minify(unsigned value,unsigned levels)720 u_minify(unsigned value, unsigned levels)
721 {
722 return MAX2(1, value >> levels);
723 }
724
725 #ifndef COPY_4V
726 #define COPY_4V( DST, SRC ) \
727 do { \
728 (DST)[0] = (SRC)[0]; \
729 (DST)[1] = (SRC)[1]; \
730 (DST)[2] = (SRC)[2]; \
731 (DST)[3] = (SRC)[3]; \
732 } while (0)
733 #endif
734
735
736 #ifndef COPY_4FV
737 #define COPY_4FV( DST, SRC ) COPY_4V(DST, SRC)
738 #endif
739
740
741 #ifndef ASSIGN_4V
742 #define ASSIGN_4V( DST, V0, V1, V2, V3 ) \
743 do { \
744 (DST)[0] = (V0); \
745 (DST)[1] = (V1); \
746 (DST)[2] = (V2); \
747 (DST)[3] = (V3); \
748 } while (0)
749 #endif
750
751
752 static inline uint32_t
util_unsigned_fixed(float value,unsigned frac_bits)753 util_unsigned_fixed(float value, unsigned frac_bits)
754 {
755 return value < 0 ? 0 : (uint32_t)(value * (1<<frac_bits));
756 }
757
758 static inline int32_t
util_signed_fixed(float value,unsigned frac_bits)759 util_signed_fixed(float value, unsigned frac_bits)
760 {
761 return (int32_t)(value * (1<<frac_bits));
762 }
763
764 unsigned
765 util_fpstate_get(void);
766 unsigned
767 util_fpstate_set_denorms_to_zero(unsigned current_fpstate);
768 void
769 util_fpstate_set(unsigned fpstate);
770
771 /**
772 * For indexed draw calls, return true if the vertex count to be drawn is
773 * much lower than the vertex count that has to be uploaded, meaning
774 * that the driver should flatten indices instead of trying to upload
775 * a too big range.
776 *
777 * This is used by vertex upload code in u_vbuf and glthread.
778 */
779 static inline bool
util_is_vbo_upload_ratio_too_large(unsigned draw_vertex_count,unsigned upload_vertex_count)780 util_is_vbo_upload_ratio_too_large(unsigned draw_vertex_count,
781 unsigned upload_vertex_count)
782 {
783 if (upload_vertex_count > 256)
784 return upload_vertex_count > draw_vertex_count * 4;
785 else if (upload_vertex_count > 64)
786 return upload_vertex_count > draw_vertex_count * 8;
787 else
788 return upload_vertex_count > draw_vertex_count * 16;
789 }
790
791 bool util_invert_mat4x4(float *out, const float *m);
792
793 /* Quantize the lod bias value to reduce the number of sampler state
794 * variants in gallium because apps use it for smooth mipmap transitions,
795 * thrashing cso_cache and degrading performance.
796 *
797 * This quantization matches the AMD hw specification, so having more
798 * precision would have no effect anyway.
799 */
800 static inline float
util_quantize_lod_bias(float lod)801 util_quantize_lod_bias(float lod)
802 {
803 lod = CLAMP(lod, -32, 31);
804 return roundf(lod * 256) / 256;
805 }
806
807 /**
808 * Adds two unsigned integers and if the addition
809 * overflows then clamp it to ~0U.
810 */
811 static inline unsigned
util_clamped_uadd(unsigned a,unsigned b)812 util_clamped_uadd(unsigned a, unsigned b)
813 {
814 unsigned res = a + b;
815 if (res < a) {
816 res = ~0U;
817 }
818 return res;
819 }
820
821 #ifdef __cplusplus
822 }
823 #endif
824
825 #endif /* U_MATH_H */
826