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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 
51 #ifdef __cplusplus
52 extern "C" {
53 #endif
54 
55 
56 #ifndef M_SQRT2
57 #define M_SQRT2 1.41421356237309504880
58 #endif
59 
60 
61 /**
62  * Initialize math module.  This should be called before using any
63  * other functions in this module.
64  */
65 extern void
66 util_init_math(void);
67 
68 
69 union fi {
70    float f;
71    int32_t i;
72    uint32_t ui;
73 };
74 
75 
76 union di {
77    double d;
78    int64_t i;
79    uint64_t ui;
80 };
81 
82 
83 /**
84  * Extract the IEEE float32 exponent.
85  */
86 static inline signed
util_get_float32_exponent(float x)87 util_get_float32_exponent(float x)
88 {
89    union fi f;
90 
91    f.f = x;
92 
93    return ((f.ui >> 23) & 0xff) - 127;
94 }
95 
96 
97 #define LOG2_TABLE_SIZE_LOG2 8
98 #define LOG2_TABLE_SCALE (1 << LOG2_TABLE_SIZE_LOG2)
99 #define LOG2_TABLE_SIZE (LOG2_TABLE_SCALE + 1)
100 extern float log2_table[LOG2_TABLE_SIZE];
101 
102 
103 /**
104  * Fast approximation to log2(x).
105  */
106 static inline float
util_fast_log2(float x)107 util_fast_log2(float x)
108 {
109    union fi num;
110    float epart, mpart;
111    num.f = x;
112    epart = (float)(((num.i & 0x7f800000) >> 23) - 127);
113    /* mpart = log2_table[mantissa*LOG2_TABLE_SCALE + 0.5] */
114    mpart = log2_table[((num.i & 0x007fffff) + (1 << (22 - LOG2_TABLE_SIZE_LOG2))) >> (23 - LOG2_TABLE_SIZE_LOG2)];
115    return epart + mpart;
116 }
117 
118 
119 /**
120  * Floor(x), returned as int.
121  */
122 static inline int
util_ifloor(float f)123 util_ifloor(float f)
124 {
125 #if defined(USE_X86_ASM) && defined(__GNUC__) && defined(__i386__)
126    /*
127     * IEEE floor for computers that round to nearest or even.
128     * 'f' must be between -4194304 and 4194303.
129     * This floor operation is done by "(iround(f + .5) + iround(f - .5)) >> 1",
130     * but uses some IEEE specific tricks for better speed.
131     * Contributed by Josh Vanderhoof
132     */
133    int ai, bi;
134    double af, bf;
135    af = (3 << 22) + 0.5 + (double)f;
136    bf = (3 << 22) + 0.5 - (double)f;
137    /* GCC generates an extra fstp/fld without this. */
138    __asm__ ("fstps %0" : "=m" (ai) : "t" (af) : "st");
139    __asm__ ("fstps %0" : "=m" (bi) : "t" (bf) : "st");
140    return (ai - bi) >> 1;
141 #else
142    int ai, bi;
143    double af, bf;
144    union fi u;
145    af = (3 << 22) + 0.5 + (double) f;
146    bf = (3 << 22) + 0.5 - (double) f;
147    u.f = (float) af;  ai = u.i;
148    u.f = (float) bf;  bi = u.i;
149    return (ai - bi) >> 1;
150 #endif
151 }
152 
153 
154 /**
155  * Round float to nearest int.
156  */
157 static inline int
util_iround(float f)158 util_iround(float f)
159 {
160 #if defined(PIPE_CC_GCC) && defined(PIPE_ARCH_X86)
161    int r;
162    __asm__ ("fistpl %0" : "=m" (r) : "t" (f) : "st");
163    return r;
164 #elif defined(PIPE_CC_MSVC) && defined(PIPE_ARCH_X86)
165    int r;
166    _asm {
167       fld f
168       fistp r
169    }
170    return r;
171 #else
172    if (f >= 0.0f)
173       return (int) (f + 0.5f);
174    else
175       return (int) (f - 0.5f);
176 #endif
177 }
178 
179 
180 /**
181  * Approximate floating point comparison
182  */
183 static inline bool
util_is_approx(float a,float b,float tol)184 util_is_approx(float a, float b, float tol)
185 {
186    return fabsf(b - a) <= tol;
187 }
188 
189 
190 /**
191  * util_is_X_inf_or_nan = test if x is NaN or +/- Inf
192  * util_is_X_nan        = test if x is NaN
193  * util_X_inf_sign      = return +1 for +Inf, -1 for -Inf, or 0 for not Inf
194  *
195  * NaN can be checked with x != x, however this fails with the fast math flag
196  **/
197 
198 
199 /**
200  * Single-float
201  */
202 static inline bool
util_is_inf_or_nan(float x)203 util_is_inf_or_nan(float x)
204 {
205    union fi tmp;
206    tmp.f = x;
207    return (tmp.ui & 0x7f800000) == 0x7f800000;
208 }
209 
210 
211 static inline bool
util_is_nan(float x)212 util_is_nan(float x)
213 {
214    union fi tmp;
215    tmp.f = x;
216    return (tmp.ui & 0x7fffffff) > 0x7f800000;
217 }
218 
219 
220 static inline int
util_inf_sign(float x)221 util_inf_sign(float x)
222 {
223    union fi tmp;
224    tmp.f = x;
225    if ((tmp.ui & 0x7fffffff) != 0x7f800000) {
226       return 0;
227    }
228 
229    return (x < 0) ? -1 : 1;
230 }
231 
232 
233 /**
234  * Double-float
235  */
236 static inline bool
util_is_double_inf_or_nan(double x)237 util_is_double_inf_or_nan(double x)
238 {
239    union di tmp;
240    tmp.d = x;
241    return (tmp.ui & 0x7ff0000000000000ULL) == 0x7ff0000000000000ULL;
242 }
243 
244 
245 static inline bool
util_is_double_nan(double x)246 util_is_double_nan(double x)
247 {
248    union di tmp;
249    tmp.d = x;
250    return (tmp.ui & 0x7fffffffffffffffULL) > 0x7ff0000000000000ULL;
251 }
252 
253 
254 static inline int
util_double_inf_sign(double x)255 util_double_inf_sign(double x)
256 {
257    union di tmp;
258    tmp.d = x;
259    if ((tmp.ui & 0x7fffffffffffffffULL) != 0x7ff0000000000000ULL) {
260       return 0;
261    }
262 
263    return (x < 0) ? -1 : 1;
264 }
265 
266 
267 /**
268  * Half-float
269  */
270 static inline bool
util_is_half_inf_or_nan(int16_t x)271 util_is_half_inf_or_nan(int16_t x)
272 {
273    return (x & 0x7c00) == 0x7c00;
274 }
275 
276 
277 static inline bool
util_is_half_nan(int16_t x)278 util_is_half_nan(int16_t x)
279 {
280    return (x & 0x7fff) > 0x7c00;
281 }
282 
283 
284 static inline int
util_half_inf_sign(int16_t x)285 util_half_inf_sign(int16_t x)
286 {
287    if ((x & 0x7fff) != 0x7c00) {
288       return 0;
289    }
290 
291    return (x < 0) ? -1 : 1;
292 }
293 
294 
295 /**
296  * Return float bits.
297  */
298 static inline unsigned
fui(float f)299 fui( float f )
300 {
301    union fi fi;
302    fi.f = f;
303    return fi.ui;
304 }
305 
306 static inline float
uif(uint32_t ui)307 uif(uint32_t ui)
308 {
309    union fi fi;
310    fi.ui = ui;
311    return fi.f;
312 }
313 
314 
315 /**
316  * Convert uint8_t to float in [0, 1].
317  */
318 static inline float
ubyte_to_float(uint8_t ub)319 ubyte_to_float(uint8_t ub)
320 {
321    return (float) ub * (1.0f / 255.0f);
322 }
323 
324 
325 /**
326  * Convert float in [0,1] to uint8_t in [0,255] with clamping.
327  */
328 static inline uint8_t
float_to_ubyte(float f)329 float_to_ubyte(float f)
330 {
331    /* return 0 for NaN too */
332    if (!(f > 0.0f)) {
333       return (uint8_t) 0;
334    }
335    else if (f >= 1.0f) {
336       return (uint8_t) 255;
337    }
338    else {
339       union fi tmp;
340       tmp.f = f;
341       tmp.f = tmp.f * (255.0f/256.0f) + 32768.0f;
342       return (uint8_t) tmp.i;
343    }
344 }
345 
346 /**
347  * Convert uint16_t to float in [0, 1].
348  */
349 static inline float
ushort_to_float(uint16_t us)350 ushort_to_float(uint16_t us)
351 {
352    return (float) us * (1.0f / 65535.0f);
353 }
354 
355 
356 /**
357  * Convert float in [0,1] to uint16_t in [0,65535] with clamping.
358  */
359 static inline uint16_t
float_to_ushort(float f)360 float_to_ushort(float f)
361 {
362    /* return 0 for NaN too */
363    if (!(f > 0.0f)) {
364       return (uint16_t) 0;
365    }
366    else if (f >= 1.0f) {
367       return (uint16_t) 65535;
368    }
369    else {
370       union fi tmp;
371       tmp.f = f;
372       tmp.f = tmp.f * (65535.0f/65536.0f) + 128.0f;
373       return (uint16_t) tmp.i;
374    }
375 }
376 
377 static inline float
byte_to_float_tex(int8_t b)378 byte_to_float_tex(int8_t b)
379 {
380    return (b == -128) ? -1.0F : b * 1.0F / 127.0F;
381 }
382 
383 static inline int8_t
float_to_byte_tex(float f)384 float_to_byte_tex(float f)
385 {
386    return (int8_t) (127.0F * f);
387 }
388 
389 /**
390  * Calc log base 2
391  */
392 static inline unsigned
util_logbase2(unsigned n)393 util_logbase2(unsigned n)
394 {
395 #if defined(HAVE___BUILTIN_CLZ)
396    return ((sizeof(unsigned) * 8 - 1) - __builtin_clz(n | 1));
397 #else
398    unsigned pos = 0;
399    if (n >= 1<<16) { n >>= 16; pos += 16; }
400    if (n >= 1<< 8) { n >>=  8; pos +=  8; }
401    if (n >= 1<< 4) { n >>=  4; pos +=  4; }
402    if (n >= 1<< 2) { n >>=  2; pos +=  2; }
403    if (n >= 1<< 1) {           pos +=  1; }
404    return pos;
405 #endif
406 }
407 
408 static inline uint64_t
util_logbase2_64(uint64_t n)409 util_logbase2_64(uint64_t n)
410 {
411 #if defined(HAVE___BUILTIN_CLZLL)
412    return ((sizeof(uint64_t) * 8 - 1) - __builtin_clzll(n | 1));
413 #else
414    uint64_t pos = 0ull;
415    if (n >= 1ull<<32) { n >>= 32; pos += 32; }
416    if (n >= 1ull<<16) { n >>= 16; pos += 16; }
417    if (n >= 1ull<< 8) { n >>=  8; pos +=  8; }
418    if (n >= 1ull<< 4) { n >>=  4; pos +=  4; }
419    if (n >= 1ull<< 2) { n >>=  2; pos +=  2; }
420    if (n >= 1ull<< 1) {           pos +=  1; }
421    return pos;
422 #endif
423 }
424 
425 /**
426  * Returns the ceiling of log n base 2, and 0 when n == 0. Equivalently,
427  * returns the smallest x such that n <= 2**x.
428  */
429 static inline unsigned
util_logbase2_ceil(unsigned n)430 util_logbase2_ceil(unsigned n)
431 {
432    if (n <= 1)
433       return 0;
434 
435    return 1 + util_logbase2(n - 1);
436 }
437 
438 static inline uint64_t
util_logbase2_ceil64(uint64_t n)439 util_logbase2_ceil64(uint64_t n)
440 {
441    if (n <= 1)
442       return 0;
443 
444    return 1ull + util_logbase2_64(n - 1);
445 }
446 
447 /**
448  * Returns the smallest power of two >= x
449  */
450 static inline unsigned
util_next_power_of_two(unsigned x)451 util_next_power_of_two(unsigned x)
452 {
453 #if defined(HAVE___BUILTIN_CLZ)
454    if (x <= 1)
455        return 1;
456 
457    return (1 << ((sizeof(unsigned) * 8) - __builtin_clz(x - 1)));
458 #else
459    unsigned val = x;
460 
461    if (x <= 1)
462       return 1;
463 
464    if (util_is_power_of_two_or_zero(x))
465       return x;
466 
467    val--;
468    val = (val >> 1) | val;
469    val = (val >> 2) | val;
470    val = (val >> 4) | val;
471    val = (val >> 8) | val;
472    val = (val >> 16) | val;
473    val++;
474    return val;
475 #endif
476 }
477 
478 static inline uint64_t
util_next_power_of_two64(uint64_t x)479 util_next_power_of_two64(uint64_t x)
480 {
481 #if defined(HAVE___BUILTIN_CLZLL)
482    if (x <= 1)
483        return 1;
484 
485    return (1ull << ((sizeof(uint64_t) * 8) - __builtin_clzll(x - 1)));
486 #else
487    uint64_t val = x;
488 
489    if (x <= 1)
490       return 1;
491 
492    if (util_is_power_of_two_or_zero64(x))
493       return x;
494 
495    val--;
496    val = (val >> 1)  | val;
497    val = (val >> 2)  | val;
498    val = (val >> 4)  | val;
499    val = (val >> 8)  | val;
500    val = (val >> 16) | val;
501    val = (val >> 32) | val;
502    val++;
503    return val;
504 #endif
505 }
506 
507 /**
508  * Reverse bits in n
509  * Algorithm taken from:
510  * http://stackoverflow.com/questions/9144800/c-reverse-bits-in-unsigned-integer
511  */
512 static inline unsigned
util_bitreverse(unsigned n)513 util_bitreverse(unsigned n)
514 {
515     n = ((n >> 1) & 0x55555555u) | ((n & 0x55555555u) << 1);
516     n = ((n >> 2) & 0x33333333u) | ((n & 0x33333333u) << 2);
517     n = ((n >> 4) & 0x0f0f0f0fu) | ((n & 0x0f0f0f0fu) << 4);
518     n = ((n >> 8) & 0x00ff00ffu) | ((n & 0x00ff00ffu) << 8);
519     n = ((n >> 16) & 0xffffu) | ((n & 0xffffu) << 16);
520     return n;
521 }
522 
523 /**
524  * Convert from little endian to CPU byte order.
525  */
526 
527 #if UTIL_ARCH_BIG_ENDIAN
528 #define util_le64_to_cpu(x) util_bswap64(x)
529 #define util_le32_to_cpu(x) util_bswap32(x)
530 #define util_le16_to_cpu(x) util_bswap16(x)
531 #else
532 #define util_le64_to_cpu(x) (x)
533 #define util_le32_to_cpu(x) (x)
534 #define util_le16_to_cpu(x) (x)
535 #endif
536 
537 #define util_cpu_to_le64(x) util_le64_to_cpu(x)
538 #define util_cpu_to_le32(x) util_le32_to_cpu(x)
539 #define util_cpu_to_le16(x) util_le16_to_cpu(x)
540 
541 /**
542  * Reverse byte order of a 32 bit word.
543  */
544 static inline uint32_t
util_bswap32(uint32_t n)545 util_bswap32(uint32_t n)
546 {
547 #if defined(HAVE___BUILTIN_BSWAP32)
548    return __builtin_bswap32(n);
549 #else
550    return (n >> 24) |
551           ((n >> 8) & 0x0000ff00) |
552           ((n << 8) & 0x00ff0000) |
553           (n << 24);
554 #endif
555 }
556 
557 /**
558  * Reverse byte order of a 64bit word.
559  */
560 static inline uint64_t
util_bswap64(uint64_t n)561 util_bswap64(uint64_t n)
562 {
563 #if defined(HAVE___BUILTIN_BSWAP64)
564    return __builtin_bswap64(n);
565 #else
566    return ((uint64_t)util_bswap32((uint32_t)n) << 32) |
567           util_bswap32((n >> 32));
568 #endif
569 }
570 
571 
572 /**
573  * Reverse byte order of a 16 bit word.
574  */
575 static inline uint16_t
util_bswap16(uint16_t n)576 util_bswap16(uint16_t n)
577 {
578    return (n >> 8) |
579           (n << 8);
580 }
581 
582 /**
583  * Mask and sign-extend a number
584  *
585  * The bit at position `width - 1` is replicated to all the higher bits.
586  * This makes no assumptions about the high bits of the value and will
587  * overwrite them with the sign bit.
588  */
589 static inline int64_t
util_mask_sign_extend(uint64_t val,unsigned width)590 util_mask_sign_extend(uint64_t val, unsigned width)
591 {
592    assert(width > 0 && width <= 64);
593    unsigned shift = 64 - width;
594    return (int64_t)(val << shift) >> shift;
595 }
596 
597 /**
598  * Sign-extend a number
599  *
600  * The bit at position `width - 1` is replicated to all the higher bits.
601  * This assumes and asserts that the value fits into `width` bits.
602  */
603 static inline int64_t
util_sign_extend(uint64_t val,unsigned width)604 util_sign_extend(uint64_t val, unsigned width)
605 {
606    assert(width == 64 || val < (UINT64_C(1) << width));
607    return util_mask_sign_extend(val, width);
608 }
609 
610 static inline void*
util_memcpy_cpu_to_le32(void * restrict dest,const void * restrict src,size_t n)611 util_memcpy_cpu_to_le32(void * restrict dest, const void * restrict src, size_t n)
612 {
613 #if UTIL_ARCH_BIG_ENDIAN
614    size_t i, e;
615    assert(n % 4 == 0);
616 
617    for (i = 0, e = n / 4; i < e; i++) {
618       uint32_t * restrict d = (uint32_t* restrict)dest;
619       const uint32_t * restrict s = (const uint32_t* restrict)src;
620       d[i] = util_bswap32(s[i]);
621    }
622    return dest;
623 #else
624    return memcpy(dest, src, n);
625 #endif
626 }
627 
628 /**
629  * Clamp X to [MIN, MAX].
630  * This is a macro to allow float, int, uint, etc. types.
631  * We arbitrarily turn NaN into MIN.
632  */
633 #define CLAMP( X, MIN, MAX )  ( (X)>(MIN) ? ((X)>(MAX) ? (MAX) : (X)) : (MIN) )
634 
635 /* Syntax sugar occuring frequently in graphics code */
636 #define SATURATE( X ) CLAMP(X, 0.0f, 1.0f)
637 
638 #define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
639 #define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
640 
641 #define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
642 #define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
643 
644 #define MIN4( A, B, C, D ) ((A) < (B) ? MIN3(A, C, D) : MIN3(B, C, D))
645 #define MAX4( A, B, C, D ) ((A) > (B) ? MAX3(A, C, D) : MAX3(B, C, D))
646 
647 
648 /**
649  * Align a value up to an alignment value
650  *
651  * If \c value is not already aligned to the requested alignment value, it
652  * will be rounded up.
653  *
654  * \param value  Value to be rounded
655  * \param alignment  Alignment value to be used.  This must be a power of two.
656  *
657  * \sa ROUND_DOWN_TO()
658  */
659 
660 #if defined(ALIGN)
661 #undef ALIGN
662 #endif
663 static inline uintptr_t
ALIGN(uintptr_t value,int32_t alignment)664 ALIGN(uintptr_t value, int32_t alignment)
665 {
666    assert(util_is_power_of_two_nonzero(alignment));
667    return (((value) + (alignment) - 1) & ~((alignment) - 1));
668 }
669 
670 /**
671  * Like ALIGN(), but works with a non-power-of-two alignment.
672  */
673 static inline uintptr_t
ALIGN_NPOT(uintptr_t value,int32_t alignment)674 ALIGN_NPOT(uintptr_t value, int32_t alignment)
675 {
676    assert(alignment > 0);
677    return (value + alignment - 1) / alignment * alignment;
678 }
679 
680 /**
681  * Align a value down to an alignment value
682  *
683  * If \c value is not already aligned to the requested alignment value, it
684  * will be rounded down.
685  *
686  * \param value  Value to be rounded
687  * \param alignment  Alignment value to be used.  This must be a power of two.
688  *
689  * \sa ALIGN()
690  */
691 static inline uint64_t
ROUND_DOWN_TO(uint64_t value,int32_t alignment)692 ROUND_DOWN_TO(uint64_t value, int32_t alignment)
693 {
694    assert(util_is_power_of_two_nonzero(alignment));
695    return ((value) & ~(alignment - 1));
696 }
697 
698 /**
699  * Align a value, only works pot alignemnts.
700  */
701 static inline int
align(int value,int alignment)702 align(int value, int alignment)
703 {
704    return (value + alignment - 1) & ~(alignment - 1);
705 }
706 
707 static inline uint64_t
align64(uint64_t value,unsigned alignment)708 align64(uint64_t value, unsigned alignment)
709 {
710    return (value + alignment - 1) & ~((uint64_t)alignment - 1);
711 }
712 
713 /**
714  * Works like align but on npot alignments.
715  */
716 static inline size_t
util_align_npot(size_t value,size_t alignment)717 util_align_npot(size_t value, size_t alignment)
718 {
719    if (value % alignment)
720       return value + (alignment - (value % alignment));
721    return value;
722 }
723 
724 static inline unsigned
u_minify(unsigned value,unsigned levels)725 u_minify(unsigned value, unsigned levels)
726 {
727     return MAX2(1, value >> levels);
728 }
729 
730 #ifndef COPY_4V
731 #define COPY_4V( DST, SRC )         \
732 do {                                \
733    (DST)[0] = (SRC)[0];             \
734    (DST)[1] = (SRC)[1];             \
735    (DST)[2] = (SRC)[2];             \
736    (DST)[3] = (SRC)[3];             \
737 } while (0)
738 #endif
739 
740 
741 #ifndef COPY_4FV
742 #define COPY_4FV( DST, SRC )  COPY_4V(DST, SRC)
743 #endif
744 
745 
746 #ifndef ASSIGN_4V
747 #define ASSIGN_4V( DST, V0, V1, V2, V3 ) \
748 do {                                     \
749    (DST)[0] = (V0);                      \
750    (DST)[1] = (V1);                      \
751    (DST)[2] = (V2);                      \
752    (DST)[3] = (V3);                      \
753 } while (0)
754 #endif
755 
756 
757 static inline uint32_t
util_unsigned_fixed(float value,unsigned frac_bits)758 util_unsigned_fixed(float value, unsigned frac_bits)
759 {
760    return value < 0 ? 0 : (uint32_t)(value * (1<<frac_bits));
761 }
762 
763 static inline int32_t
util_signed_fixed(float value,unsigned frac_bits)764 util_signed_fixed(float value, unsigned frac_bits)
765 {
766    return (int32_t)(value * (1<<frac_bits));
767 }
768 
769 unsigned
770 util_fpstate_get(void);
771 unsigned
772 util_fpstate_set_denorms_to_zero(unsigned current_fpstate);
773 void
774 util_fpstate_set(unsigned fpstate);
775 
776 /**
777  * For indexed draw calls, return true if the vertex count to be drawn is
778  * much lower than the vertex count that has to be uploaded, meaning
779  * that the driver should flatten indices instead of trying to upload
780  * a too big range.
781  *
782  * This is used by vertex upload code in u_vbuf and glthread.
783  */
784 static inline bool
util_is_vbo_upload_ratio_too_large(unsigned draw_vertex_count,unsigned upload_vertex_count)785 util_is_vbo_upload_ratio_too_large(unsigned draw_vertex_count,
786                                    unsigned upload_vertex_count)
787 {
788    if (draw_vertex_count > 1024)
789       return upload_vertex_count > draw_vertex_count * 4;
790    else if (draw_vertex_count > 32)
791       return upload_vertex_count > draw_vertex_count * 8;
792    else
793       return upload_vertex_count > draw_vertex_count * 16;
794 }
795 
796 bool util_invert_mat4x4(float *out, const float *m);
797 
798 /* Quantize the lod bias value to reduce the number of sampler state
799  * variants in gallium because apps use it for smooth mipmap transitions,
800  * thrashing cso_cache and degrading performance.
801  *
802  * This quantization matches the AMD hw specification, so having more
803  * precision would have no effect anyway.
804  */
805 static inline float
util_quantize_lod_bias(float lod)806 util_quantize_lod_bias(float lod)
807 {
808    lod = CLAMP(lod, -16, 16);
809    return roundf(lod * 256) / 256;
810 }
811 
812 #ifdef __cplusplus
813 }
814 #endif
815 
816 #endif /* U_MATH_H */
817