lp_bld_const.c revision 3469715a8a171512cf9b528702e70393f01c6041 
1/**************************************************************************
2 *
3 * Copyright 2009 VMware, Inc.
4 * All Rights Reserved.
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6 * Permission is hereby granted, free of charge, to any person obtaining a
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11 * permit persons to whom the Software is furnished to do so, subject to
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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 *
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19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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27
28
29/**
30 * @file
31 * Helper functions for constant building.
32 *
33 * @author Jose Fonseca <jfonseca@vmware.com>
34 */
35
36#include <float.h>
37
38#include "util/u_debug.h"
39#include "util/u_math.h"
40#include "util/u_half.h"
41
42#include "lp_bld_type.h"
43#include "lp_bld_const.h"
44#include "lp_bld_init.h"
45
46
47unsigned
48lp_mantissa(struct lp_type type)
49{
50   assert(type.floating);
51
52   if(type.floating) {
53      switch(type.width) {
54      case 16:
55         return 10;
56      case 32:
57         return 23;
58      case 64:
59         return 52;
60      default:
61         assert(0);
62         return 0;
63      }
64   }
65   else {
66      if(type.sign)
67         return type.width - 1;
68      else
69         return type.width;
70   }
71}
72
73
74/**
75 * Shift of the unity.
76 *
77 * Same as lp_const_scale(), but in terms of shifts.
78 */
79unsigned
80lp_const_shift(struct lp_type type)
81{
82   if(type.floating)
83      return 0;
84   else if(type.fixed)
85      return type.width/2;
86   else if(type.norm)
87      return type.sign ? type.width - 1 : type.width;
88   else
89      return 0;
90}
91
92
93unsigned
94lp_const_offset(struct lp_type type)
95{
96   if(type.floating || type.fixed)
97      return 0;
98   else if(type.norm)
99      return 1;
100   else
101      return 0;
102}
103
104
105/**
106 * Scaling factor between the LLVM native value and its interpretation.
107 *
108 * This is 1.0 for all floating types and unnormalized integers, and something
109 * else for the fixed points types and normalized integers.
110 */
111double
112lp_const_scale(struct lp_type type)
113{
114   unsigned long long llscale;
115   double dscale;
116
117   llscale = (unsigned long long)1 << lp_const_shift(type);
118   llscale -= lp_const_offset(type);
119   dscale = (double)llscale;
120   assert((unsigned long long)dscale == llscale);
121
122   return dscale;
123}
124
125
126/**
127 * Minimum value representable by the type.
128 */
129double
130lp_const_min(struct lp_type type)
131{
132   unsigned bits;
133
134   if(!type.sign)
135      return 0.0;
136
137   if(type.norm)
138      return -1.0;
139
140   if (type.floating) {
141      switch(type.width) {
142      case 16:
143         return -65504;
144      case 32:
145         return -FLT_MAX;
146      case 64:
147         return -DBL_MAX;
148      default:
149         assert(0);
150         return 0.0;
151      }
152   }
153
154   if(type.fixed)
155      /* FIXME: consider the fractional bits? */
156      bits = type.width / 2 - 1;
157   else
158      bits = type.width - 1;
159
160   return (double)-((long long)1 << bits);
161}
162
163
164/**
165 * Maximum value representable by the type.
166 */
167double
168lp_const_max(struct lp_type type)
169{
170   unsigned bits;
171
172   if(type.norm)
173      return 1.0;
174
175   if (type.floating) {
176      switch(type.width) {
177      case 16:
178         return 65504;
179      case 32:
180         return FLT_MAX;
181      case 64:
182         return DBL_MAX;
183      default:
184         assert(0);
185         return 0.0;
186      }
187   }
188
189   if(type.fixed)
190      bits = type.width / 2;
191   else
192      bits = type.width;
193
194   if(type.sign)
195      bits -= 1;
196
197   return (double)(((unsigned long long)1 << bits) - 1);
198}
199
200
201double
202lp_const_eps(struct lp_type type)
203{
204   if (type.floating) {
205      switch(type.width) {
206      case 16:
207         return 2E-10;
208      case 32:
209         return FLT_EPSILON;
210      case 64:
211         return DBL_EPSILON;
212      default:
213         assert(0);
214         return 0.0;
215      }
216   }
217   else {
218      double scale = lp_const_scale(type);
219      return 1.0/scale;
220   }
221}
222
223
224LLVMValueRef
225lp_build_undef(struct gallivm_state *gallivm, struct lp_type type)
226{
227   LLVMTypeRef vec_type = lp_build_vec_type(gallivm, type);
228   return LLVMGetUndef(vec_type);
229}
230
231
232LLVMValueRef
233lp_build_zero(struct gallivm_state *gallivm, struct lp_type type)
234{
235   if (type.length == 1) {
236      if (type.floating)
237         return lp_build_const_float(gallivm, 0.0);
238      else
239         return LLVMConstInt(LLVMIntTypeInContext(gallivm->context, type.width), 0, 0);
240   }
241   else {
242      LLVMTypeRef vec_type = lp_build_vec_type(gallivm, type);
243      return LLVMConstNull(vec_type);
244   }
245}
246
247
248LLVMValueRef
249lp_build_one(struct gallivm_state *gallivm, struct lp_type type)
250{
251   LLVMTypeRef elem_type;
252   LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
253   unsigned i;
254
255   assert(type.length <= LP_MAX_VECTOR_LENGTH);
256
257   elem_type = lp_build_elem_type(gallivm, type);
258
259   if(type.floating && type.width == 16)
260      elems[0] = LLVMConstInt(elem_type, util_float_to_half(1.0f), 0);
261   else if(type.floating)
262      elems[0] = LLVMConstReal(elem_type, 1.0);
263   else if(type.fixed)
264      elems[0] = LLVMConstInt(elem_type, 1LL << (type.width/2), 0);
265   else if(!type.norm)
266      elems[0] = LLVMConstInt(elem_type, 1, 0);
267   else if(type.sign)
268      elems[0] = LLVMConstInt(elem_type, (1LL << (type.width - 1)) - 1, 0);
269   else {
270      /* special case' -- 1.0 for normalized types is more easily attained if
271       * we start with a vector consisting of all bits set */
272      LLVMTypeRef vec_type = LLVMVectorType(elem_type, type.length);
273      LLVMValueRef vec = LLVMConstAllOnes(vec_type);
274
275#if 0
276      if(type.sign)
277         /* TODO: Unfortunately this caused "Tried to create a shift operation
278          * on a non-integer type!" */
279         vec = LLVMConstLShr(vec, lp_build_const_int_vec(type, 1));
280#endif
281
282      return vec;
283   }
284
285   for(i = 1; i < type.length; ++i)
286      elems[i] = elems[0];
287
288   if (type.length == 1)
289      return elems[0];
290   else
291      return LLVMConstVector(elems, type.length);
292}
293
294
295/**
296 * Build constant-valued element from a scalar value.
297 */
298LLVMValueRef
299lp_build_const_elem(struct gallivm_state *gallivm,
300                    struct lp_type type,
301                    double val)
302{
303   LLVMTypeRef elem_type = lp_build_elem_type(gallivm, type);
304   LLVMValueRef elem;
305
306   if(type.floating && type.width == 16) {
307      elem = LLVMConstInt(elem_type, util_float_to_half((float)val), 0);
308   } else if(type.floating) {
309      elem = LLVMConstReal(elem_type, val);
310   }
311   else {
312      double dscale = lp_const_scale(type);
313
314      elem = LLVMConstInt(elem_type, round(val*dscale), 0);
315   }
316
317   return elem;
318}
319
320
321/**
322 * Build constant-valued vector from a scalar value.
323 */
324LLVMValueRef
325lp_build_const_vec(struct gallivm_state *gallivm, struct lp_type type,
326                   double val)
327{
328   if (type.length == 1) {
329      return lp_build_const_elem(gallivm, type, val);
330   } else {
331      LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
332      unsigned i;
333      elems[0] = lp_build_const_elem(gallivm, type, val);
334      for(i = 1; i < type.length; ++i)
335         elems[i] = elems[0];
336      return LLVMConstVector(elems, type.length);
337   }
338}
339
340
341LLVMValueRef
342lp_build_const_int_vec(struct gallivm_state *gallivm, struct lp_type type,
343                       long long val)
344{
345   LLVMTypeRef elem_type = lp_build_int_elem_type(gallivm, type);
346   LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
347   unsigned i;
348
349   assert(type.length <= LP_MAX_VECTOR_LENGTH);
350
351   for(i = 0; i < type.length; ++i)
352      elems[i] = LLVMConstInt(elem_type, val, type.sign ? 1 : 0);
353
354   if (type.length == 1)
355      return elems[0];
356
357   return LLVMConstVector(elems, type.length);
358}
359
360
361LLVMValueRef
362lp_build_const_aos(struct gallivm_state *gallivm,
363                   struct lp_type type,
364                   double r, double g, double b, double a,
365                   const unsigned char *swizzle)
366{
367   const unsigned char default_swizzle[4] = {0, 1, 2, 3};
368   LLVMTypeRef elem_type;
369   LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
370   unsigned i;
371
372   assert(type.length % 4 == 0);
373   assert(type.length <= LP_MAX_VECTOR_LENGTH);
374
375   elem_type = lp_build_elem_type(gallivm, type);
376
377   if(swizzle == NULL)
378      swizzle = default_swizzle;
379
380   elems[swizzle[0]] = lp_build_const_elem(gallivm, type, r);
381   elems[swizzle[1]] = lp_build_const_elem(gallivm, type, g);
382   elems[swizzle[2]] = lp_build_const_elem(gallivm, type, b);
383   elems[swizzle[3]] = lp_build_const_elem(gallivm, type, a);
384
385   for(i = 4; i < type.length; ++i)
386      elems[i] = elems[i % 4];
387
388   return LLVMConstVector(elems, type.length);
389}
390
391
392/**
393 * @param mask TGSI_WRITEMASK_xxx
394 */
395LLVMValueRef
396lp_build_const_mask_aos(struct gallivm_state *gallivm,
397                        struct lp_type type,
398                        unsigned mask)
399{
400   LLVMTypeRef elem_type = LLVMIntTypeInContext(gallivm->context, type.width);
401   LLVMValueRef masks[LP_MAX_VECTOR_LENGTH];
402   unsigned i, j;
403
404   assert(type.length <= LP_MAX_VECTOR_LENGTH);
405
406   for (j = 0; j < type.length; j += 4) {
407      for( i = 0; i < 4; ++i) {
408         masks[j + i] = LLVMConstInt(elem_type,
409                                     mask & (1 << i) ? ~0ULL : 0,
410                                     1);
411      }
412   }
413
414   return LLVMConstVector(masks, type.length);
415}
416
417
418/**
419 * Performs lp_build_const_mask_aos, but first swizzles the mask
420 */
421LLVMValueRef
422lp_build_const_mask_aos_swizzled(struct gallivm_state *gallivm,
423                        struct lp_type type,
424                        unsigned mask,
425                        const unsigned char *swizzle)
426{
427   mask =
428           ((mask & (1 << swizzle[0])) >> swizzle[0])
429        | (((mask & (1 << swizzle[1])) >> swizzle[1]) << 1)
430        | (((mask & (1 << swizzle[2])) >> swizzle[2]) << 2)
431        | (((mask & (1 << swizzle[3])) >> swizzle[3]) << 3);
432
433   return lp_build_const_mask_aos(gallivm, type, mask);
434}
435
436
437/**
438 * Build a zero-terminated constant string.
439 */
440LLVMValueRef
441lp_build_const_string(struct gallivm_state *gallivm,
442                      const char *str)
443{
444   unsigned len = strlen(str) + 1;
445   LLVMTypeRef i8 = LLVMInt8TypeInContext(gallivm->context);
446   LLVMValueRef string = LLVMAddGlobal(gallivm->module, LLVMArrayType(i8, len), "");
447   LLVMSetGlobalConstant(string, TRUE);
448   LLVMSetLinkage(string, LLVMInternalLinkage);
449   LLVMSetInitializer(string, LLVMConstStringInContext(gallivm->context, str, len, TRUE));
450   string = LLVMConstBitCast(string, LLVMPointerType(i8, 0));
451   return string;
452}
453
454
455/**
456 * Build a callable function pointer.
457 *
458 * We use function pointer constants instead of LLVMAddGlobalMapping()
459 * to work around a bug in LLVM 2.6, and for efficiency/simplicity.
460 */
461LLVMValueRef
462lp_build_const_func_pointer(struct gallivm_state *gallivm,
463                            const void *ptr,
464                            LLVMTypeRef ret_type,
465                            LLVMTypeRef *arg_types,
466                            unsigned num_args,
467                            const char *name)
468{
469   LLVMTypeRef function_type;
470   LLVMValueRef function;
471
472   function_type = LLVMFunctionType(ret_type, arg_types, num_args, 0);
473
474   function = lp_build_const_int_pointer(gallivm, ptr);
475
476   function = LLVMBuildBitCast(gallivm->builder, function,
477                               LLVMPointerType(function_type, 0),
478                               name);
479
480   return function;
481}
482