1/*
2 * Copyright © 2015 Intel Corporation
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 (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 *    Jason Ekstrand (jason@jlekstrand.net)
25 *
26 */
27
28#include "vtn_private.h"
29#include "GLSL.std.450.h"
30
31#define M_PIf   ((float) M_PI)
32#define M_PI_2f ((float) M_PI_2)
33#define M_PI_4f ((float) M_PI_4)
34
35static nir_ssa_def *
36build_mat2_det(nir_builder *b, nir_ssa_def *col[2])
37{
38   unsigned swiz[4] = {1, 0, 0, 0};
39   nir_ssa_def *p = nir_fmul(b, col[0], nir_swizzle(b, col[1], swiz, 2, true));
40   return nir_fsub(b, nir_channel(b, p, 0), nir_channel(b, p, 1));
41}
42
43static nir_ssa_def *
44build_mat3_det(nir_builder *b, nir_ssa_def *col[3])
45{
46   unsigned yzx[4] = {1, 2, 0, 0};
47   unsigned zxy[4] = {2, 0, 1, 0};
48
49   nir_ssa_def *prod0 =
50      nir_fmul(b, col[0],
51               nir_fmul(b, nir_swizzle(b, col[1], yzx, 3, true),
52                           nir_swizzle(b, col[2], zxy, 3, true)));
53   nir_ssa_def *prod1 =
54      nir_fmul(b, col[0],
55               nir_fmul(b, nir_swizzle(b, col[1], zxy, 3, true),
56                           nir_swizzle(b, col[2], yzx, 3, true)));
57
58   nir_ssa_def *diff = nir_fsub(b, prod0, prod1);
59
60   return nir_fadd(b, nir_channel(b, diff, 0),
61                      nir_fadd(b, nir_channel(b, diff, 1),
62                                  nir_channel(b, diff, 2)));
63}
64
65static nir_ssa_def *
66build_mat4_det(nir_builder *b, nir_ssa_def **col)
67{
68   nir_ssa_def *subdet[4];
69   for (unsigned i = 0; i < 4; i++) {
70      unsigned swiz[3];
71      for (unsigned j = 0; j < 3; j++)
72         swiz[j] = j + (j >= i);
73
74      nir_ssa_def *subcol[3];
75      subcol[0] = nir_swizzle(b, col[1], swiz, 3, true);
76      subcol[1] = nir_swizzle(b, col[2], swiz, 3, true);
77      subcol[2] = nir_swizzle(b, col[3], swiz, 3, true);
78
79      subdet[i] = build_mat3_det(b, subcol);
80   }
81
82   nir_ssa_def *prod = nir_fmul(b, col[0], nir_vec(b, subdet, 4));
83
84   return nir_fadd(b, nir_fsub(b, nir_channel(b, prod, 0),
85                                  nir_channel(b, prod, 1)),
86                      nir_fsub(b, nir_channel(b, prod, 2),
87                                  nir_channel(b, prod, 3)));
88}
89
90static nir_ssa_def *
91build_mat_det(struct vtn_builder *b, struct vtn_ssa_value *src)
92{
93   unsigned size = glsl_get_vector_elements(src->type);
94
95   nir_ssa_def *cols[4];
96   for (unsigned i = 0; i < size; i++)
97      cols[i] = src->elems[i]->def;
98
99   switch(size) {
100   case 2: return build_mat2_det(&b->nb, cols);
101   case 3: return build_mat3_det(&b->nb, cols);
102   case 4: return build_mat4_det(&b->nb, cols);
103   default:
104      unreachable("Invalid matrix size");
105   }
106}
107
108/* Computes the determinate of the submatrix given by taking src and
109 * removing the specified row and column.
110 */
111static nir_ssa_def *
112build_mat_subdet(struct nir_builder *b, struct vtn_ssa_value *src,
113                 unsigned size, unsigned row, unsigned col)
114{
115   assert(row < size && col < size);
116   if (size == 2) {
117      return nir_channel(b, src->elems[1 - col]->def, 1 - row);
118   } else {
119      /* Swizzle to get all but the specified row */
120      unsigned swiz[3];
121      for (unsigned j = 0; j < 3; j++)
122         swiz[j] = j + (j >= row);
123
124      /* Grab all but the specified column */
125      nir_ssa_def *subcol[3];
126      for (unsigned j = 0; j < size; j++) {
127         if (j != col) {
128            subcol[j - (j > col)] = nir_swizzle(b, src->elems[j]->def,
129                                                swiz, size - 1, true);
130         }
131      }
132
133      if (size == 3) {
134         return build_mat2_det(b, subcol);
135      } else {
136         assert(size == 4);
137         return build_mat3_det(b, subcol);
138      }
139   }
140}
141
142static struct vtn_ssa_value *
143matrix_inverse(struct vtn_builder *b, struct vtn_ssa_value *src)
144{
145   nir_ssa_def *adj_col[4];
146   unsigned size = glsl_get_vector_elements(src->type);
147
148   /* Build up an adjugate matrix */
149   for (unsigned c = 0; c < size; c++) {
150      nir_ssa_def *elem[4];
151      for (unsigned r = 0; r < size; r++) {
152         elem[r] = build_mat_subdet(&b->nb, src, size, c, r);
153
154         if ((r + c) % 2)
155            elem[r] = nir_fneg(&b->nb, elem[r]);
156      }
157
158      adj_col[c] = nir_vec(&b->nb, elem, size);
159   }
160
161   nir_ssa_def *det_inv = nir_frcp(&b->nb, build_mat_det(b, src));
162
163   struct vtn_ssa_value *val = vtn_create_ssa_value(b, src->type);
164   for (unsigned i = 0; i < size; i++)
165      val->elems[i]->def = nir_fmul(&b->nb, adj_col[i], det_inv);
166
167   return val;
168}
169
170static nir_ssa_def*
171build_length(nir_builder *b, nir_ssa_def *vec)
172{
173   switch (vec->num_components) {
174   case 1: return nir_fsqrt(b, nir_fmul(b, vec, vec));
175   case 2: return nir_fsqrt(b, nir_fdot2(b, vec, vec));
176   case 3: return nir_fsqrt(b, nir_fdot3(b, vec, vec));
177   case 4: return nir_fsqrt(b, nir_fdot4(b, vec, vec));
178   default:
179      unreachable("Invalid number of components");
180   }
181}
182
183static inline nir_ssa_def *
184build_fclamp(nir_builder *b,
185             nir_ssa_def *x, nir_ssa_def *min_val, nir_ssa_def *max_val)
186{
187   return nir_fmin(b, nir_fmax(b, x, min_val), max_val);
188}
189
190/**
191 * Return e^x.
192 */
193static nir_ssa_def *
194build_exp(nir_builder *b, nir_ssa_def *x)
195{
196   return nir_fexp2(b, nir_fmul(b, x, nir_imm_float(b, M_LOG2E)));
197}
198
199/**
200 * Return ln(x) - the natural logarithm of x.
201 */
202static nir_ssa_def *
203build_log(nir_builder *b, nir_ssa_def *x)
204{
205   return nir_fmul(b, nir_flog2(b, x), nir_imm_float(b, 1.0 / M_LOG2E));
206}
207
208/**
209 * Approximate asin(x) by the formula:
210 *    asin~(x) = sign(x) * (pi/2 - sqrt(1 - |x|) * (pi/2 + |x|(pi/4 - 1 + |x|(p0 + |x|p1))))
211 *
212 * which is correct to first order at x=0 and x=±1 regardless of the p
213 * coefficients but can be made second-order correct at both ends by selecting
214 * the fit coefficients appropriately.  Different p coefficients can be used
215 * in the asin and acos implementation to minimize some relative error metric
216 * in each case.
217 */
218static nir_ssa_def *
219build_asin(nir_builder *b, nir_ssa_def *x, float p0, float p1)
220{
221   nir_ssa_def *abs_x = nir_fabs(b, x);
222   return nir_fmul(b, nir_fsign(b, x),
223                   nir_fsub(b, nir_imm_float(b, M_PI_2f),
224                            nir_fmul(b, nir_fsqrt(b, nir_fsub(b, nir_imm_float(b, 1.0f), abs_x)),
225                                     nir_fadd(b, nir_imm_float(b, M_PI_2f),
226                                              nir_fmul(b, abs_x,
227                                                       nir_fadd(b, nir_imm_float(b, M_PI_4f - 1.0f),
228                                                                nir_fmul(b, abs_x,
229                                                                         nir_fadd(b, nir_imm_float(b, p0),
230                                                                                  nir_fmul(b, abs_x,
231                                                                                           nir_imm_float(b, p1))))))))));
232}
233
234/**
235 * Compute xs[0] + xs[1] + xs[2] + ... using fadd.
236 */
237static nir_ssa_def *
238build_fsum(nir_builder *b, nir_ssa_def **xs, int terms)
239{
240   nir_ssa_def *accum = xs[0];
241
242   for (int i = 1; i < terms; i++)
243      accum = nir_fadd(b, accum, xs[i]);
244
245   return accum;
246}
247
248static nir_ssa_def *
249build_atan(nir_builder *b, nir_ssa_def *y_over_x)
250{
251   nir_ssa_def *abs_y_over_x = nir_fabs(b, y_over_x);
252   nir_ssa_def *one = nir_imm_float(b, 1.0f);
253
254   /*
255    * range-reduction, first step:
256    *
257    *      / y_over_x         if |y_over_x| <= 1.0;
258    * x = <
259    *      \ 1.0 / y_over_x   otherwise
260    */
261   nir_ssa_def *x = nir_fdiv(b, nir_fmin(b, abs_y_over_x, one),
262                                nir_fmax(b, abs_y_over_x, one));
263
264   /*
265    * approximate atan by evaluating polynomial:
266    *
267    * x   * 0.9999793128310355 - x^3  * 0.3326756418091246 +
268    * x^5 * 0.1938924977115610 - x^7  * 0.1173503194786851 +
269    * x^9 * 0.0536813784310406 - x^11 * 0.0121323213173444
270    */
271   nir_ssa_def *x_2  = nir_fmul(b, x,   x);
272   nir_ssa_def *x_3  = nir_fmul(b, x_2, x);
273   nir_ssa_def *x_5  = nir_fmul(b, x_3, x_2);
274   nir_ssa_def *x_7  = nir_fmul(b, x_5, x_2);
275   nir_ssa_def *x_9  = nir_fmul(b, x_7, x_2);
276   nir_ssa_def *x_11 = nir_fmul(b, x_9, x_2);
277
278   nir_ssa_def *polynomial_terms[] = {
279      nir_fmul(b, x,    nir_imm_float(b,  0.9999793128310355f)),
280      nir_fmul(b, x_3,  nir_imm_float(b, -0.3326756418091246f)),
281      nir_fmul(b, x_5,  nir_imm_float(b,  0.1938924977115610f)),
282      nir_fmul(b, x_7,  nir_imm_float(b, -0.1173503194786851f)),
283      nir_fmul(b, x_9,  nir_imm_float(b,  0.0536813784310406f)),
284      nir_fmul(b, x_11, nir_imm_float(b, -0.0121323213173444f)),
285   };
286
287   nir_ssa_def *tmp =
288      build_fsum(b, polynomial_terms, ARRAY_SIZE(polynomial_terms));
289
290   /* range-reduction fixup */
291   tmp = nir_fadd(b, tmp,
292                  nir_fmul(b,
293                           nir_b2f(b, nir_flt(b, one, abs_y_over_x)),
294                           nir_fadd(b, nir_fmul(b, tmp,
295                                                nir_imm_float(b, -2.0f)),
296                                       nir_imm_float(b, M_PI_2f))));
297
298   /* sign fixup */
299   return nir_fmul(b, tmp, nir_fsign(b, y_over_x));
300}
301
302static nir_ssa_def *
303build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
304{
305   nir_ssa_def *zero = nir_imm_float(b, 0.0f);
306
307   /* If |x| >= 1.0e-8 * |y|: */
308   nir_ssa_def *condition =
309      nir_fge(b, nir_fabs(b, x),
310              nir_fmul(b, nir_imm_float(b, 1.0e-8f), nir_fabs(b, y)));
311
312   /* Then...call atan(y/x) and fix it up: */
313   nir_ssa_def *atan1 = build_atan(b, nir_fdiv(b, y, x));
314   nir_ssa_def *r_then =
315      nir_bcsel(b, nir_flt(b, x, zero),
316                   nir_fadd(b, atan1,
317                               nir_bcsel(b, nir_fge(b, y, zero),
318                                            nir_imm_float(b, M_PIf),
319                                            nir_imm_float(b, -M_PIf))),
320                   atan1);
321
322   /* Else... */
323   nir_ssa_def *r_else =
324      nir_fmul(b, nir_fsign(b, y), nir_imm_float(b, M_PI_2f));
325
326   return nir_bcsel(b, condition, r_then, r_else);
327}
328
329static nir_ssa_def *
330build_frexp(nir_builder *b, nir_ssa_def *x, nir_ssa_def **exponent)
331{
332   nir_ssa_def *abs_x = nir_fabs(b, x);
333   nir_ssa_def *zero = nir_imm_float(b, 0.0f);
334
335   /* Single-precision floating-point values are stored as
336    *   1 sign bit;
337    *   8 exponent bits;
338    *   23 mantissa bits.
339    *
340    * An exponent shift of 23 will shift the mantissa out, leaving only the
341    * exponent and sign bit (which itself may be zero, if the absolute value
342    * was taken before the bitcast and shift.
343    */
344   nir_ssa_def *exponent_shift = nir_imm_int(b, 23);
345   nir_ssa_def *exponent_bias = nir_imm_int(b, -126);
346
347   nir_ssa_def *sign_mantissa_mask = nir_imm_int(b, 0x807fffffu);
348
349   /* Exponent of floating-point values in the range [0.5, 1.0). */
350   nir_ssa_def *exponent_value = nir_imm_int(b, 0x3f000000u);
351
352   nir_ssa_def *is_not_zero = nir_fne(b, abs_x, zero);
353
354   *exponent =
355      nir_iadd(b, nir_ushr(b, abs_x, exponent_shift),
356                  nir_bcsel(b, is_not_zero, exponent_bias, zero));
357
358   return nir_ior(b, nir_iand(b, x, sign_mantissa_mask),
359                     nir_bcsel(b, is_not_zero, exponent_value, zero));
360}
361
362static nir_op
363vtn_nir_alu_op_for_spirv_glsl_opcode(enum GLSLstd450 opcode)
364{
365   switch (opcode) {
366   case GLSLstd450Round:         return nir_op_fround_even;
367   case GLSLstd450RoundEven:     return nir_op_fround_even;
368   case GLSLstd450Trunc:         return nir_op_ftrunc;
369   case GLSLstd450FAbs:          return nir_op_fabs;
370   case GLSLstd450SAbs:          return nir_op_iabs;
371   case GLSLstd450FSign:         return nir_op_fsign;
372   case GLSLstd450SSign:         return nir_op_isign;
373   case GLSLstd450Floor:         return nir_op_ffloor;
374   case GLSLstd450Ceil:          return nir_op_fceil;
375   case GLSLstd450Fract:         return nir_op_ffract;
376   case GLSLstd450Sin:           return nir_op_fsin;
377   case GLSLstd450Cos:           return nir_op_fcos;
378   case GLSLstd450Pow:           return nir_op_fpow;
379   case GLSLstd450Exp2:          return nir_op_fexp2;
380   case GLSLstd450Log2:          return nir_op_flog2;
381   case GLSLstd450Sqrt:          return nir_op_fsqrt;
382   case GLSLstd450InverseSqrt:   return nir_op_frsq;
383   case GLSLstd450FMin:          return nir_op_fmin;
384   case GLSLstd450UMin:          return nir_op_umin;
385   case GLSLstd450SMin:          return nir_op_imin;
386   case GLSLstd450FMax:          return nir_op_fmax;
387   case GLSLstd450UMax:          return nir_op_umax;
388   case GLSLstd450SMax:          return nir_op_imax;
389   case GLSLstd450FMix:          return nir_op_flrp;
390   case GLSLstd450Fma:           return nir_op_ffma;
391   case GLSLstd450Ldexp:         return nir_op_ldexp;
392   case GLSLstd450FindILsb:      return nir_op_find_lsb;
393   case GLSLstd450FindSMsb:      return nir_op_ifind_msb;
394   case GLSLstd450FindUMsb:      return nir_op_ufind_msb;
395
396   /* Packing/Unpacking functions */
397   case GLSLstd450PackSnorm4x8:     return nir_op_pack_snorm_4x8;
398   case GLSLstd450PackUnorm4x8:     return nir_op_pack_unorm_4x8;
399   case GLSLstd450PackSnorm2x16:    return nir_op_pack_snorm_2x16;
400   case GLSLstd450PackUnorm2x16:    return nir_op_pack_unorm_2x16;
401   case GLSLstd450PackHalf2x16:     return nir_op_pack_half_2x16;
402   case GLSLstd450PackDouble2x32:   return nir_op_pack_double_2x32;
403   case GLSLstd450UnpackSnorm4x8:   return nir_op_unpack_snorm_4x8;
404   case GLSLstd450UnpackUnorm4x8:   return nir_op_unpack_unorm_4x8;
405   case GLSLstd450UnpackSnorm2x16:  return nir_op_unpack_snorm_2x16;
406   case GLSLstd450UnpackUnorm2x16:  return nir_op_unpack_unorm_2x16;
407   case GLSLstd450UnpackHalf2x16:   return nir_op_unpack_half_2x16;
408   case GLSLstd450UnpackDouble2x32: return nir_op_unpack_double_2x32;
409
410   default:
411      unreachable("No NIR equivalent");
412   }
413}
414
415static void
416handle_glsl450_alu(struct vtn_builder *b, enum GLSLstd450 entrypoint,
417                   const uint32_t *w, unsigned count)
418{
419   struct nir_builder *nb = &b->nb;
420   const struct glsl_type *dest_type =
421      vtn_value(b, w[1], vtn_value_type_type)->type->type;
422
423   struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa);
424   val->ssa = vtn_create_ssa_value(b, dest_type);
425
426   /* Collect the various SSA sources */
427   unsigned num_inputs = count - 5;
428   nir_ssa_def *src[3] = { NULL, };
429   for (unsigned i = 0; i < num_inputs; i++)
430      src[i] = vtn_ssa_value(b, w[i + 5])->def;
431
432   switch (entrypoint) {
433   case GLSLstd450Radians:
434      val->ssa->def = nir_fmul(nb, src[0], nir_imm_float(nb, 0.01745329251));
435      return;
436   case GLSLstd450Degrees:
437      val->ssa->def = nir_fmul(nb, src[0], nir_imm_float(nb, 57.2957795131));
438      return;
439   case GLSLstd450Tan:
440      val->ssa->def = nir_fdiv(nb, nir_fsin(nb, src[0]),
441                               nir_fcos(nb, src[0]));
442      return;
443
444   case GLSLstd450Modf: {
445      nir_ssa_def *sign = nir_fsign(nb, src[0]);
446      nir_ssa_def *abs = nir_fabs(nb, src[0]);
447      val->ssa->def = nir_fmul(nb, sign, nir_ffract(nb, abs));
448      nir_store_deref_var(nb, vtn_nir_deref(b, w[6]),
449                          nir_fmul(nb, sign, nir_ffloor(nb, abs)), 0xf);
450      return;
451   }
452
453   case GLSLstd450ModfStruct: {
454      nir_ssa_def *sign = nir_fsign(nb, src[0]);
455      nir_ssa_def *abs = nir_fabs(nb, src[0]);
456      assert(glsl_type_is_struct(val->ssa->type));
457      val->ssa->elems[0]->def = nir_fmul(nb, sign, nir_ffract(nb, abs));
458      val->ssa->elems[1]->def = nir_fmul(nb, sign, nir_ffloor(nb, abs));
459      return;
460   }
461
462   case GLSLstd450Step:
463      val->ssa->def = nir_sge(nb, src[1], src[0]);
464      return;
465
466   case GLSLstd450Length:
467      val->ssa->def = build_length(nb, src[0]);
468      return;
469   case GLSLstd450Distance:
470      val->ssa->def = build_length(nb, nir_fsub(nb, src[0], src[1]));
471      return;
472   case GLSLstd450Normalize:
473      val->ssa->def = nir_fdiv(nb, src[0], build_length(nb, src[0]));
474      return;
475
476   case GLSLstd450Exp:
477      val->ssa->def = build_exp(nb, src[0]);
478      return;
479
480   case GLSLstd450Log:
481      val->ssa->def = build_log(nb, src[0]);
482      return;
483
484   case GLSLstd450FClamp:
485      val->ssa->def = build_fclamp(nb, src[0], src[1], src[2]);
486      return;
487   case GLSLstd450UClamp:
488      val->ssa->def = nir_umin(nb, nir_umax(nb, src[0], src[1]), src[2]);
489      return;
490   case GLSLstd450SClamp:
491      val->ssa->def = nir_imin(nb, nir_imax(nb, src[0], src[1]), src[2]);
492      return;
493
494   case GLSLstd450Cross: {
495      unsigned yzx[4] = { 1, 2, 0, 0 };
496      unsigned zxy[4] = { 2, 0, 1, 0 };
497      val->ssa->def =
498         nir_fsub(nb, nir_fmul(nb, nir_swizzle(nb, src[0], yzx, 3, true),
499                                   nir_swizzle(nb, src[1], zxy, 3, true)),
500                      nir_fmul(nb, nir_swizzle(nb, src[0], zxy, 3, true),
501                                   nir_swizzle(nb, src[1], yzx, 3, true)));
502      return;
503   }
504
505   case GLSLstd450SmoothStep: {
506      /* t = clamp((x - edge0) / (edge1 - edge0), 0, 1) */
507      nir_ssa_def *t =
508         build_fclamp(nb, nir_fdiv(nb, nir_fsub(nb, src[2], src[0]),
509                                       nir_fsub(nb, src[1], src[0])),
510                          nir_imm_float(nb, 0.0), nir_imm_float(nb, 1.0));
511      /* result = t * t * (3 - 2 * t) */
512      val->ssa->def =
513         nir_fmul(nb, t, nir_fmul(nb, t,
514            nir_fsub(nb, nir_imm_float(nb, 3.0),
515                         nir_fmul(nb, nir_imm_float(nb, 2.0), t))));
516      return;
517   }
518
519   case GLSLstd450FaceForward:
520      val->ssa->def =
521         nir_bcsel(nb, nir_flt(nb, nir_fdot(nb, src[2], src[1]),
522                                   nir_imm_float(nb, 0.0)),
523                       src[0], nir_fneg(nb, src[0]));
524      return;
525
526   case GLSLstd450Reflect:
527      /* I - 2 * dot(N, I) * N */
528      val->ssa->def =
529         nir_fsub(nb, src[0], nir_fmul(nb, nir_imm_float(nb, 2.0),
530                              nir_fmul(nb, nir_fdot(nb, src[0], src[1]),
531                                           src[1])));
532      return;
533
534   case GLSLstd450Refract: {
535      nir_ssa_def *I = src[0];
536      nir_ssa_def *N = src[1];
537      nir_ssa_def *eta = src[2];
538      nir_ssa_def *n_dot_i = nir_fdot(nb, N, I);
539      nir_ssa_def *one = nir_imm_float(nb, 1.0);
540      nir_ssa_def *zero = nir_imm_float(nb, 0.0);
541      /* k = 1.0 - eta * eta * (1.0 - dot(N, I) * dot(N, I)) */
542      nir_ssa_def *k =
543         nir_fsub(nb, one, nir_fmul(nb, eta, nir_fmul(nb, eta,
544                      nir_fsub(nb, one, nir_fmul(nb, n_dot_i, n_dot_i)))));
545      nir_ssa_def *result =
546         nir_fsub(nb, nir_fmul(nb, eta, I),
547                      nir_fmul(nb, nir_fadd(nb, nir_fmul(nb, eta, n_dot_i),
548                                                nir_fsqrt(nb, k)), N));
549      /* XXX: bcsel, or if statement? */
550      val->ssa->def = nir_bcsel(nb, nir_flt(nb, k, zero), zero, result);
551      return;
552   }
553
554   case GLSLstd450Sinh:
555      /* 0.5 * (e^x - e^(-x)) */
556      val->ssa->def =
557         nir_fmul(nb, nir_imm_float(nb, 0.5f),
558                      nir_fsub(nb, build_exp(nb, src[0]),
559                                   build_exp(nb, nir_fneg(nb, src[0]))));
560      return;
561
562   case GLSLstd450Cosh:
563      /* 0.5 * (e^x + e^(-x)) */
564      val->ssa->def =
565         nir_fmul(nb, nir_imm_float(nb, 0.5f),
566                      nir_fadd(nb, build_exp(nb, src[0]),
567                                   build_exp(nb, nir_fneg(nb, src[0]))));
568      return;
569
570   case GLSLstd450Tanh: {
571      /* tanh(x) := (0.5 * (e^x - e^(-x))) / (0.5 * (e^x + e^(-x)))
572       *
573       * With a little algebra this reduces to (e^2x - 1) / (e^2x + 1)
574       *
575       * We clamp x to (-inf, +10] to avoid precision problems.  When x > 10,
576       * e^2x is so much larger than 1.0 that 1.0 gets flushed to zero in the
577       * computation e^2x +/- 1 so it can be ignored.
578       */
579      nir_ssa_def *x = nir_fmin(nb, src[0], nir_imm_float(nb, 10));
580      nir_ssa_def *exp2x = build_exp(nb, nir_fmul(nb, x, nir_imm_float(nb, 2)));
581      val->ssa->def = nir_fdiv(nb, nir_fsub(nb, exp2x, nir_imm_float(nb, 1)),
582                                   nir_fadd(nb, exp2x, nir_imm_float(nb, 1)));
583      return;
584   }
585
586   case GLSLstd450Asinh:
587      val->ssa->def = nir_fmul(nb, nir_fsign(nb, src[0]),
588         build_log(nb, nir_fadd(nb, nir_fabs(nb, src[0]),
589                       nir_fsqrt(nb, nir_fadd(nb, nir_fmul(nb, src[0], src[0]),
590                                                  nir_imm_float(nb, 1.0f))))));
591      return;
592   case GLSLstd450Acosh:
593      val->ssa->def = build_log(nb, nir_fadd(nb, src[0],
594         nir_fsqrt(nb, nir_fsub(nb, nir_fmul(nb, src[0], src[0]),
595                                    nir_imm_float(nb, 1.0f)))));
596      return;
597   case GLSLstd450Atanh: {
598      nir_ssa_def *one = nir_imm_float(nb, 1.0);
599      val->ssa->def = nir_fmul(nb, nir_imm_float(nb, 0.5f),
600         build_log(nb, nir_fdiv(nb, nir_fadd(nb, one, src[0]),
601                                    nir_fsub(nb, one, src[0]))));
602      return;
603   }
604
605   case GLSLstd450Asin:
606      val->ssa->def = build_asin(nb, src[0], 0.086566724, -0.03102955);
607      return;
608
609   case GLSLstd450Acos:
610      val->ssa->def = nir_fsub(nb, nir_imm_float(nb, M_PI_2f),
611                               build_asin(nb, src[0], 0.08132463, -0.02363318));
612      return;
613
614   case GLSLstd450Atan:
615      val->ssa->def = build_atan(nb, src[0]);
616      return;
617
618   case GLSLstd450Atan2:
619      val->ssa->def = build_atan2(nb, src[0], src[1]);
620      return;
621
622   case GLSLstd450Frexp: {
623      nir_ssa_def *exponent;
624      val->ssa->def = build_frexp(nb, src[0], &exponent);
625      nir_store_deref_var(nb, vtn_nir_deref(b, w[6]), exponent, 0xf);
626      return;
627   }
628
629   case GLSLstd450FrexpStruct: {
630      assert(glsl_type_is_struct(val->ssa->type));
631      val->ssa->elems[0]->def = build_frexp(nb, src[0],
632                                            &val->ssa->elems[1]->def);
633      return;
634   }
635
636   default:
637      val->ssa->def =
638         nir_build_alu(&b->nb, vtn_nir_alu_op_for_spirv_glsl_opcode(entrypoint),
639                       src[0], src[1], src[2], NULL);
640      return;
641   }
642}
643
644static void
645handle_glsl450_interpolation(struct vtn_builder *b, enum GLSLstd450 opcode,
646                             const uint32_t *w, unsigned count)
647{
648   const struct glsl_type *dest_type =
649      vtn_value(b, w[1], vtn_value_type_type)->type->type;
650
651   struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa);
652   val->ssa = vtn_create_ssa_value(b, dest_type);
653
654   nir_intrinsic_op op;
655   switch (opcode) {
656   case GLSLstd450InterpolateAtCentroid:
657      op = nir_intrinsic_interp_var_at_centroid;
658      break;
659   case GLSLstd450InterpolateAtSample:
660      op = nir_intrinsic_interp_var_at_sample;
661      break;
662   case GLSLstd450InterpolateAtOffset:
663      op = nir_intrinsic_interp_var_at_offset;
664      break;
665   default:
666      unreachable("Invalid opcode");
667   }
668
669   nir_intrinsic_instr *intrin = nir_intrinsic_instr_create(b->nb.shader, op);
670
671   nir_deref_var *deref = vtn_nir_deref(b, w[5]);
672   intrin->variables[0] = nir_deref_var_clone(deref, intrin);
673
674   switch (opcode) {
675   case GLSLstd450InterpolateAtCentroid:
676      break;
677   case GLSLstd450InterpolateAtSample:
678   case GLSLstd450InterpolateAtOffset:
679      intrin->src[0] = nir_src_for_ssa(vtn_ssa_value(b, w[6])->def);
680      break;
681   default:
682      unreachable("Invalid opcode");
683   }
684
685   intrin->num_components = glsl_get_vector_elements(dest_type);
686   nir_ssa_dest_init(&intrin->instr, &intrin->dest,
687                     glsl_get_vector_elements(dest_type),
688                     glsl_get_bit_size(dest_type), NULL);
689   val->ssa->def = &intrin->dest.ssa;
690
691   nir_builder_instr_insert(&b->nb, &intrin->instr);
692}
693
694bool
695vtn_handle_glsl450_instruction(struct vtn_builder *b, uint32_t ext_opcode,
696                               const uint32_t *w, unsigned count)
697{
698   switch ((enum GLSLstd450)ext_opcode) {
699   case GLSLstd450Determinant: {
700      struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa);
701      val->ssa = rzalloc(b, struct vtn_ssa_value);
702      val->ssa->type = vtn_value(b, w[1], vtn_value_type_type)->type->type;
703      val->ssa->def = build_mat_det(b, vtn_ssa_value(b, w[5]));
704      break;
705   }
706
707   case GLSLstd450MatrixInverse: {
708      struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa);
709      val->ssa = matrix_inverse(b, vtn_ssa_value(b, w[5]));
710      break;
711   }
712
713   case GLSLstd450InterpolateAtCentroid:
714   case GLSLstd450InterpolateAtSample:
715   case GLSLstd450InterpolateAtOffset:
716      handle_glsl450_interpolation(b, ext_opcode, w, count);
717      break;
718
719   default:
720      handle_glsl450_alu(b, (enum GLSLstd450)ext_opcode, w, count);
721   }
722
723   return true;
724}
725