1 /*
2 Copyright (C) Intel Corp. 2006. All Rights Reserved.
3 Intel funded Tungsten Graphics to
4 develop this 3D driver.
5
6 Permission is hereby granted, free of charge, to any person obtaining
7 a 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, sublicense, 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
16 portions of the Software.
17
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
21 IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25
26 **********************************************************************/
27 /*
28 * Authors:
29 * Keith Whitwell <keithw@vmware.com>
30 */
31
32
33 #include "main/macros.h"
34 #include "main/enums.h"
35
36 #include "program/program.h"
37 #include "intel_batchbuffer.h"
38
39 #include "brw_defines.h"
40 #include "brw_context.h"
41 #include "brw_eu.h"
42 #include "brw_ff_gs.h"
43
44 /**
45 * Allocate registers for GS.
46 *
47 * If sol_program is true, then:
48 *
49 * - The thread will be spawned with the "SVBI Payload Enable" bit set, so GRF
50 * 1 needs to be set aside to hold the streamed vertex buffer indices.
51 *
52 * - The thread will need to use the destination_indices register.
53 */
brw_ff_gs_alloc_regs(struct brw_ff_gs_compile * c,GLuint nr_verts,bool sol_program)54 static void brw_ff_gs_alloc_regs(struct brw_ff_gs_compile *c,
55 GLuint nr_verts,
56 bool sol_program)
57 {
58 GLuint i = 0,j;
59
60 /* Register usage is static, precompute here:
61 */
62 c->reg.R0 = retype(brw_vec8_grf(i, 0), BRW_REGISTER_TYPE_UD); i++;
63
64 /* Streamed vertex buffer indices */
65 if (sol_program)
66 c->reg.SVBI = retype(brw_vec8_grf(i++, 0), BRW_REGISTER_TYPE_UD);
67
68 /* Payload vertices plus space for more generated vertices:
69 */
70 for (j = 0; j < nr_verts; j++) {
71 c->reg.vertex[j] = brw_vec4_grf(i, 0);
72 i += c->nr_regs;
73 }
74
75 c->reg.header = retype(brw_vec8_grf(i++, 0), BRW_REGISTER_TYPE_UD);
76 c->reg.temp = retype(brw_vec8_grf(i++, 0), BRW_REGISTER_TYPE_UD);
77
78 if (sol_program) {
79 c->reg.destination_indices =
80 retype(brw_vec4_grf(i++, 0), BRW_REGISTER_TYPE_UD);
81 }
82
83 c->prog_data.urb_read_length = c->nr_regs;
84 c->prog_data.total_grf = i;
85 }
86
87
88 /**
89 * Set up the initial value of c->reg.header register based on c->reg.R0.
90 *
91 * The following information is passed to the GS thread in R0, and needs to be
92 * included in the first URB_WRITE or FF_SYNC message sent by the GS:
93 *
94 * - DWORD 0 [31:0] handle info (Gen4 only)
95 * - DWORD 5 [7:0] FFTID
96 * - DWORD 6 [31:0] Debug info
97 * - DWORD 7 [31:0] Debug info
98 *
99 * This function sets up the above data by copying by copying the contents of
100 * R0 to the header register.
101 */
brw_ff_gs_initialize_header(struct brw_ff_gs_compile * c)102 static void brw_ff_gs_initialize_header(struct brw_ff_gs_compile *c)
103 {
104 struct brw_codegen *p = &c->func;
105 brw_MOV(p, c->reg.header, c->reg.R0);
106 }
107
108 /**
109 * Overwrite DWORD 2 of c->reg.header with the given immediate unsigned value.
110 *
111 * In URB_WRITE messages, DWORD 2 contains the fields PrimType, PrimStart,
112 * PrimEnd, Increment CL_INVOCATIONS, and SONumPrimsWritten, many of which we
113 * need to be able to update on a per-vertex basis.
114 */
brw_ff_gs_overwrite_header_dw2(struct brw_ff_gs_compile * c,unsigned dw2)115 static void brw_ff_gs_overwrite_header_dw2(struct brw_ff_gs_compile *c,
116 unsigned dw2)
117 {
118 struct brw_codegen *p = &c->func;
119 brw_MOV(p, get_element_ud(c->reg.header, 2), brw_imm_ud(dw2));
120 }
121
122 /**
123 * Overwrite DWORD 2 of c->reg.header with the primitive type from c->reg.R0.
124 *
125 * When the thread is spawned, GRF 0 contains the primitive type in bits 4:0
126 * of DWORD 2. URB_WRITE messages need the primitive type in bits 6:2 of
127 * DWORD 2. So this function extracts the primitive type field, bitshifts it
128 * appropriately, and stores it in c->reg.header.
129 */
brw_ff_gs_overwrite_header_dw2_from_r0(struct brw_ff_gs_compile * c)130 static void brw_ff_gs_overwrite_header_dw2_from_r0(struct brw_ff_gs_compile *c)
131 {
132 struct brw_codegen *p = &c->func;
133 brw_AND(p, get_element_ud(c->reg.header, 2), get_element_ud(c->reg.R0, 2),
134 brw_imm_ud(0x1f));
135 brw_SHL(p, get_element_ud(c->reg.header, 2),
136 get_element_ud(c->reg.header, 2), brw_imm_ud(2));
137 }
138
139 /**
140 * Apply an additive offset to DWORD 2 of c->reg.header.
141 *
142 * This is used to set/unset the "PrimStart" and "PrimEnd" flags appropriately
143 * for each vertex.
144 */
brw_ff_gs_offset_header_dw2(struct brw_ff_gs_compile * c,int offset)145 static void brw_ff_gs_offset_header_dw2(struct brw_ff_gs_compile *c,
146 int offset)
147 {
148 struct brw_codegen *p = &c->func;
149 brw_ADD(p, get_element_d(c->reg.header, 2), get_element_d(c->reg.header, 2),
150 brw_imm_d(offset));
151 }
152
153
154 /**
155 * Emit a vertex using the URB_WRITE message. Use the contents of
156 * c->reg.header for the message header, and the registers starting at \c vert
157 * for the vertex data.
158 *
159 * If \c last is true, then this is the last vertex, so no further URB space
160 * should be allocated, and this message should end the thread.
161 *
162 * If \c last is false, then a new URB entry will be allocated, and its handle
163 * will be stored in DWORD 0 of c->reg.header for use in the next URB_WRITE
164 * message.
165 */
brw_ff_gs_emit_vue(struct brw_ff_gs_compile * c,struct brw_reg vert,bool last)166 static void brw_ff_gs_emit_vue(struct brw_ff_gs_compile *c,
167 struct brw_reg vert,
168 bool last)
169 {
170 struct brw_codegen *p = &c->func;
171 int write_offset = 0;
172 bool complete = false;
173
174 do {
175 /* We can't write more than 14 registers at a time to the URB */
176 int write_len = MIN2(c->nr_regs - write_offset, 14);
177 if (write_len == c->nr_regs - write_offset)
178 complete = true;
179
180 /* Copy the vertex from vertn into m1..mN+1:
181 */
182 brw_copy8(p, brw_message_reg(1), offset(vert, write_offset), write_len);
183
184 /* Send the vertex data to the URB. If this is the last write for this
185 * vertex, then we mark it as complete, and either end the thread or
186 * allocate another vertex URB entry (depending whether this is the last
187 * vertex).
188 */
189 enum brw_urb_write_flags flags;
190 if (!complete)
191 flags = BRW_URB_WRITE_NO_FLAGS;
192 else if (last)
193 flags = BRW_URB_WRITE_EOT_COMPLETE;
194 else
195 flags = BRW_URB_WRITE_ALLOCATE_COMPLETE;
196 brw_urb_WRITE(p,
197 (flags & BRW_URB_WRITE_ALLOCATE) ? c->reg.temp
198 : retype(brw_null_reg(), BRW_REGISTER_TYPE_UD),
199 0,
200 c->reg.header,
201 flags,
202 write_len + 1, /* msg length */
203 (flags & BRW_URB_WRITE_ALLOCATE) ? 1
204 : 0, /* response length */
205 write_offset, /* urb offset */
206 BRW_URB_SWIZZLE_NONE);
207 write_offset += write_len;
208 } while (!complete);
209
210 if (!last) {
211 brw_MOV(p, get_element_ud(c->reg.header, 0),
212 get_element_ud(c->reg.temp, 0));
213 }
214 }
215
216 /**
217 * Send an FF_SYNC message to ensure that all previously spawned GS threads
218 * have finished sending primitives down the pipeline, and to allocate a URB
219 * entry for the first output vertex. Only needed on Ironlake+.
220 *
221 * This function modifies c->reg.header: in DWORD 1, it stores num_prim (which
222 * is needed by the FF_SYNC message), and in DWORD 0, it stores the handle to
223 * the allocated URB entry (which will be needed by the URB_WRITE meesage that
224 * follows).
225 */
brw_ff_gs_ff_sync(struct brw_ff_gs_compile * c,int num_prim)226 static void brw_ff_gs_ff_sync(struct brw_ff_gs_compile *c, int num_prim)
227 {
228 struct brw_codegen *p = &c->func;
229
230 brw_MOV(p, get_element_ud(c->reg.header, 1), brw_imm_ud(num_prim));
231 brw_ff_sync(p,
232 c->reg.temp,
233 0,
234 c->reg.header,
235 1, /* allocate */
236 1, /* response length */
237 0 /* eot */);
238 brw_MOV(p, get_element_ud(c->reg.header, 0),
239 get_element_ud(c->reg.temp, 0));
240 }
241
242
243 void
brw_ff_gs_quads(struct brw_ff_gs_compile * c,struct brw_ff_gs_prog_key * key)244 brw_ff_gs_quads(struct brw_ff_gs_compile *c, struct brw_ff_gs_prog_key *key)
245 {
246 brw_ff_gs_alloc_regs(c, 4, false);
247 brw_ff_gs_initialize_header(c);
248 /* Use polygons for correct edgeflag behaviour. Note that vertex 3
249 * is the PV for quads, but vertex 0 for polygons:
250 */
251 if (c->func.devinfo->gen == 5)
252 brw_ff_gs_ff_sync(c, 1);
253 brw_ff_gs_overwrite_header_dw2(
254 c, ((_3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT)
255 | URB_WRITE_PRIM_START));
256 if (key->pv_first) {
257 brw_ff_gs_emit_vue(c, c->reg.vertex[0], 0);
258 brw_ff_gs_overwrite_header_dw2(
259 c, _3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT);
260 brw_ff_gs_emit_vue(c, c->reg.vertex[1], 0);
261 brw_ff_gs_emit_vue(c, c->reg.vertex[2], 0);
262 brw_ff_gs_overwrite_header_dw2(
263 c, ((_3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT)
264 | URB_WRITE_PRIM_END));
265 brw_ff_gs_emit_vue(c, c->reg.vertex[3], 1);
266 }
267 else {
268 brw_ff_gs_emit_vue(c, c->reg.vertex[3], 0);
269 brw_ff_gs_overwrite_header_dw2(
270 c, _3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT);
271 brw_ff_gs_emit_vue(c, c->reg.vertex[0], 0);
272 brw_ff_gs_emit_vue(c, c->reg.vertex[1], 0);
273 brw_ff_gs_overwrite_header_dw2(
274 c, ((_3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT)
275 | URB_WRITE_PRIM_END));
276 brw_ff_gs_emit_vue(c, c->reg.vertex[2], 1);
277 }
278 }
279
280 void
brw_ff_gs_quad_strip(struct brw_ff_gs_compile * c,struct brw_ff_gs_prog_key * key)281 brw_ff_gs_quad_strip(struct brw_ff_gs_compile *c,
282 struct brw_ff_gs_prog_key *key)
283 {
284 brw_ff_gs_alloc_regs(c, 4, false);
285 brw_ff_gs_initialize_header(c);
286
287 if (c->func.devinfo->gen == 5)
288 brw_ff_gs_ff_sync(c, 1);
289 brw_ff_gs_overwrite_header_dw2(
290 c, ((_3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT)
291 | URB_WRITE_PRIM_START));
292 if (key->pv_first) {
293 brw_ff_gs_emit_vue(c, c->reg.vertex[0], 0);
294 brw_ff_gs_overwrite_header_dw2(
295 c, _3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT);
296 brw_ff_gs_emit_vue(c, c->reg.vertex[1], 0);
297 brw_ff_gs_emit_vue(c, c->reg.vertex[2], 0);
298 brw_ff_gs_overwrite_header_dw2(
299 c, ((_3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT)
300 | URB_WRITE_PRIM_END));
301 brw_ff_gs_emit_vue(c, c->reg.vertex[3], 1);
302 }
303 else {
304 brw_ff_gs_emit_vue(c, c->reg.vertex[2], 0);
305 brw_ff_gs_overwrite_header_dw2(
306 c, _3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT);
307 brw_ff_gs_emit_vue(c, c->reg.vertex[3], 0);
308 brw_ff_gs_emit_vue(c, c->reg.vertex[0], 0);
309 brw_ff_gs_overwrite_header_dw2(
310 c, ((_3DPRIM_POLYGON << URB_WRITE_PRIM_TYPE_SHIFT)
311 | URB_WRITE_PRIM_END));
312 brw_ff_gs_emit_vue(c, c->reg.vertex[1], 1);
313 }
314 }
315
brw_ff_gs_lines(struct brw_ff_gs_compile * c)316 void brw_ff_gs_lines(struct brw_ff_gs_compile *c)
317 {
318 brw_ff_gs_alloc_regs(c, 2, false);
319 brw_ff_gs_initialize_header(c);
320
321 if (c->func.devinfo->gen == 5)
322 brw_ff_gs_ff_sync(c, 1);
323 brw_ff_gs_overwrite_header_dw2(
324 c, ((_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
325 | URB_WRITE_PRIM_START));
326 brw_ff_gs_emit_vue(c, c->reg.vertex[0], 0);
327 brw_ff_gs_overwrite_header_dw2(
328 c, ((_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
329 | URB_WRITE_PRIM_END));
330 brw_ff_gs_emit_vue(c, c->reg.vertex[1], 1);
331 }
332
333 /**
334 * Generate the geometry shader program used on Gen6 to perform stream output
335 * (transform feedback).
336 */
337 void
gen6_sol_program(struct brw_ff_gs_compile * c,struct brw_ff_gs_prog_key * key,unsigned num_verts,bool check_edge_flags)338 gen6_sol_program(struct brw_ff_gs_compile *c, struct brw_ff_gs_prog_key *key,
339 unsigned num_verts, bool check_edge_flags)
340 {
341 struct brw_codegen *p = &c->func;
342 brw_inst *inst;
343 c->prog_data.svbi_postincrement_value = num_verts;
344
345 brw_ff_gs_alloc_regs(c, num_verts, true);
346 brw_ff_gs_initialize_header(c);
347
348 if (key->num_transform_feedback_bindings > 0) {
349 unsigned vertex, binding;
350 struct brw_reg destination_indices_uw =
351 vec8(retype(c->reg.destination_indices, BRW_REGISTER_TYPE_UW));
352
353 /* Note: since we use the binding table to keep track of buffer offsets
354 * and stride, the GS doesn't need to keep track of a separate pointer
355 * into each buffer; it uses a single pointer which increments by 1 for
356 * each vertex. So we use SVBI0 for this pointer, regardless of whether
357 * transform feedback is in interleaved or separate attribs mode.
358 *
359 * Make sure that the buffers have enough room for all the vertices.
360 */
361 brw_ADD(p, get_element_ud(c->reg.temp, 0),
362 get_element_ud(c->reg.SVBI, 0), brw_imm_ud(num_verts));
363 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_LE,
364 get_element_ud(c->reg.temp, 0),
365 get_element_ud(c->reg.SVBI, 4));
366 brw_IF(p, BRW_EXECUTE_1);
367
368 /* Compute the destination indices to write to. Usually we use SVBI[0]
369 * + (0, 1, 2). However, for odd-numbered triangles in tristrips, the
370 * vertices come down the pipeline in reversed winding order, so we need
371 * to flip the order when writing to the transform feedback buffer. To
372 * ensure that flatshading accuracy is preserved, we need to write them
373 * in order SVBI[0] + (0, 2, 1) if we're using the first provoking
374 * vertex convention, and in order SVBI[0] + (1, 0, 2) if we're using
375 * the last provoking vertex convention.
376 *
377 * Note: since brw_imm_v can only be used in instructions in
378 * packed-word execution mode, and SVBI is a double-word, we need to
379 * first move the appropriate immediate constant ((0, 1, 2), (0, 2, 1),
380 * or (1, 0, 2)) to the destination_indices register, and then add SVBI
381 * using a separate instruction. Also, since the immediate constant is
382 * expressed as packed words, and we need to load double-words into
383 * destination_indices, we need to intersperse zeros to fill the upper
384 * halves of each double-word.
385 */
386 brw_MOV(p, destination_indices_uw,
387 brw_imm_v(0x00020100)); /* (0, 1, 2) */
388 if (num_verts == 3) {
389 /* Get primitive type into temp register. */
390 brw_AND(p, get_element_ud(c->reg.temp, 0),
391 get_element_ud(c->reg.R0, 2), brw_imm_ud(0x1f));
392
393 /* Test if primitive type is TRISTRIP_REVERSE. We need to do this as
394 * an 8-wide comparison so that the conditional MOV that follows
395 * moves all 8 words correctly.
396 */
397 brw_CMP(p, vec8(brw_null_reg()), BRW_CONDITIONAL_EQ,
398 get_element_ud(c->reg.temp, 0),
399 brw_imm_ud(_3DPRIM_TRISTRIP_REVERSE));
400
401 /* If so, then overwrite destination_indices_uw with the appropriate
402 * reordering.
403 */
404 inst = brw_MOV(p, destination_indices_uw,
405 brw_imm_v(key->pv_first ? 0x00010200 /* (0, 2, 1) */
406 : 0x00020001)); /* (1, 0, 2) */
407 brw_inst_set_pred_control(p->devinfo, inst, BRW_PREDICATE_NORMAL);
408 }
409
410 assert(c->reg.destination_indices.width == BRW_EXECUTE_4);
411 brw_push_insn_state(p);
412 brw_set_default_exec_size(p, BRW_EXECUTE_4);
413 brw_ADD(p, c->reg.destination_indices,
414 c->reg.destination_indices, get_element_ud(c->reg.SVBI, 0));
415 brw_pop_insn_state(p);
416 /* For each vertex, generate code to output each varying using the
417 * appropriate binding table entry.
418 */
419 for (vertex = 0; vertex < num_verts; ++vertex) {
420 /* Set up the correct destination index for this vertex */
421 brw_MOV(p, get_element_ud(c->reg.header, 5),
422 get_element_ud(c->reg.destination_indices, vertex));
423
424 for (binding = 0; binding < key->num_transform_feedback_bindings;
425 ++binding) {
426 unsigned char varying =
427 key->transform_feedback_bindings[binding];
428 unsigned char slot = c->vue_map.varying_to_slot[varying];
429 /* From the Sandybridge PRM, Volume 2, Part 1, Section 4.5.1:
430 *
431 * "Prior to End of Thread with a URB_WRITE, the kernel must
432 * ensure that all writes are complete by sending the final
433 * write as a committed write."
434 */
435 bool final_write =
436 binding == key->num_transform_feedback_bindings - 1 &&
437 vertex == num_verts - 1;
438 struct brw_reg vertex_slot = c->reg.vertex[vertex];
439 vertex_slot.nr += slot / 2;
440 vertex_slot.subnr = (slot % 2) * 16;
441 /* gl_PointSize is stored in VARYING_SLOT_PSIZ.w. */
442 vertex_slot.swizzle = varying == VARYING_SLOT_PSIZ
443 ? BRW_SWIZZLE_WWWW : key->transform_feedback_swizzles[binding];
444 brw_set_default_access_mode(p, BRW_ALIGN_16);
445 brw_push_insn_state(p);
446 brw_set_default_exec_size(p, BRW_EXECUTE_4);
447
448 brw_MOV(p, stride(c->reg.header, 4, 4, 1),
449 retype(vertex_slot, BRW_REGISTER_TYPE_UD));
450 brw_pop_insn_state(p);
451
452 brw_set_default_access_mode(p, BRW_ALIGN_1);
453 brw_svb_write(p,
454 final_write ? c->reg.temp : brw_null_reg(), /* dest */
455 1, /* msg_reg_nr */
456 c->reg.header, /* src0 */
457 SURF_INDEX_GEN6_SOL_BINDING(binding), /* binding_table_index */
458 final_write); /* send_commit_msg */
459 }
460 }
461 brw_ENDIF(p);
462
463 /* Now, reinitialize the header register from R0 to restore the parts of
464 * the register that we overwrote while streaming out transform feedback
465 * data.
466 */
467 brw_ff_gs_initialize_header(c);
468
469 /* Finally, wait for the write commit to occur so that we can proceed to
470 * other things safely.
471 *
472 * From the Sandybridge PRM, Volume 4, Part 1, Section 3.3:
473 *
474 * The write commit does not modify the destination register, but
475 * merely clears the dependency associated with the destination
476 * register. Thus, a simple “mov” instruction using the register as a
477 * source is sufficient to wait for the write commit to occur.
478 */
479 brw_MOV(p, c->reg.temp, c->reg.temp);
480 }
481
482 brw_ff_gs_ff_sync(c, 1);
483
484 brw_ff_gs_overwrite_header_dw2_from_r0(c);
485 switch (num_verts) {
486 case 1:
487 brw_ff_gs_offset_header_dw2(c,
488 URB_WRITE_PRIM_START | URB_WRITE_PRIM_END);
489 brw_ff_gs_emit_vue(c, c->reg.vertex[0], true);
490 break;
491 case 2:
492 brw_ff_gs_offset_header_dw2(c, URB_WRITE_PRIM_START);
493 brw_ff_gs_emit_vue(c, c->reg.vertex[0], false);
494 brw_ff_gs_offset_header_dw2(c,
495 URB_WRITE_PRIM_END - URB_WRITE_PRIM_START);
496 brw_ff_gs_emit_vue(c, c->reg.vertex[1], true);
497 break;
498 case 3:
499 if (check_edge_flags) {
500 /* Only emit vertices 0 and 1 if this is the first triangle of the
501 * polygon. Otherwise they are redundant.
502 */
503 brw_AND(p, retype(brw_null_reg(), BRW_REGISTER_TYPE_UD),
504 get_element_ud(c->reg.R0, 2),
505 brw_imm_ud(BRW_GS_EDGE_INDICATOR_0));
506 brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
507 brw_IF(p, BRW_EXECUTE_1);
508 }
509 brw_ff_gs_offset_header_dw2(c, URB_WRITE_PRIM_START);
510 brw_ff_gs_emit_vue(c, c->reg.vertex[0], false);
511 brw_ff_gs_offset_header_dw2(c, -URB_WRITE_PRIM_START);
512 brw_ff_gs_emit_vue(c, c->reg.vertex[1], false);
513 if (check_edge_flags) {
514 brw_ENDIF(p);
515 /* Only emit vertex 2 in PRIM_END mode if this is the last triangle
516 * of the polygon. Otherwise leave the primitive incomplete because
517 * there are more polygon vertices coming.
518 */
519 brw_AND(p, retype(brw_null_reg(), BRW_REGISTER_TYPE_UD),
520 get_element_ud(c->reg.R0, 2),
521 brw_imm_ud(BRW_GS_EDGE_INDICATOR_1));
522 brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
523 brw_set_default_predicate_control(p, BRW_PREDICATE_NORMAL);
524 }
525 brw_ff_gs_offset_header_dw2(c, URB_WRITE_PRIM_END);
526 brw_set_default_predicate_control(p, BRW_PREDICATE_NONE);
527 brw_ff_gs_emit_vue(c, c->reg.vertex[2], true);
528 break;
529 }
530 }
531