1 /*
2  * Copyright (C) 2019 Connor Abbott <cwabbott0@gmail.com>
3  * Copyright (C) 2019 Lyude Paul <thatslyude@gmail.com>
4  * Copyright (C) 2019 Ryan Houdek <Sonicadvance1@gmail.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23  * SOFTWARE.
24  */
25 
26 #ifndef __bifrost_h__
27 #define __bifrost_h__
28 
29 #include <stdint.h>
30 #include <stdbool.h>
31 #include <assert.h>
32 
33 #define BIFROST_DBG_MSGS        0x0001
34 #define BIFROST_DBG_SHADERS     0x0002
35 #define BIFROST_DBG_SHADERDB    0x0004
36 #define BIFROST_DBG_VERBOSE     0x0008
37 #define BIFROST_DBG_INTERNAL    0x0010
38 #define BIFROST_DBG_NOSCHED     0x0020
39 #define BIFROST_DBG_INORDER     0x0040
40 #define BIFROST_DBG_NOVALIDATE  0x0080
41 #define BIFROST_DBG_NOOPT       0x0100
42 
43 extern int bifrost_debug;
44 
45 enum bifrost_message_type {
46         BIFROST_MESSAGE_NONE       = 0,
47         BIFROST_MESSAGE_VARYING    = 1,
48         BIFROST_MESSAGE_ATTRIBUTE  = 2,
49         BIFROST_MESSAGE_TEX        = 3,
50         BIFROST_MESSAGE_VARTEX     = 4,
51         BIFROST_MESSAGE_LOAD       = 5,
52         BIFROST_MESSAGE_STORE      = 6,
53         BIFROST_MESSAGE_ATOMIC     = 7,
54         BIFROST_MESSAGE_BARRIER    = 8,
55         BIFROST_MESSAGE_BLEND      = 9,
56         BIFROST_MESSAGE_TILE       = 10,
57         /* type 11 reserved */
58         BIFROST_MESSAGE_Z_STENCIL  = 12,
59         BIFROST_MESSAGE_ATEST      = 13,
60         BIFROST_MESSAGE_JOB        = 14,
61         BIFROST_MESSAGE_64BIT      = 15
62 };
63 
64 enum bifrost_ftz {
65         BIFROST_FTZ_DISABLE = 0,
66         BIFROST_FTZ_DX11 = 1,
67         BIFROST_FTZ_ALWAYS = 2,
68         BIFROST_FTZ_ABRUPT = 3
69 };
70 
71 enum bifrost_exceptions {
72         BIFROST_EXCEPTIONS_ENABLED = 0,
73         BIFROST_EXCEPTIONS_DISABLED = 1,
74         BIFROST_EXCEPTIONS_PRECISE_DIVISION = 2,
75         BIFROST_EXCEPTIONS_PRECISE_SQRT = 3,
76 };
77 
78 /* Describes clause flow control, with respect to control flow and branch
79  * reconvergence.
80  *
81  * Control flow may be considered back-to-back (execute clauses back-to-back),
82  * non-back-to-back (switch warps after clause before the next clause), write
83  * elision (back-to-back and elide register slot #3 write from the clause), or
84  * end of shader.
85  *
86  * Branch reconvergence may be disabled, enabled unconditionally, or enabled
87  * based on the program counter. A clause requires reconvergence if it has a
88  * successor that can be executed without first executing the clause itself.
89  * Separate iterations of a loop are treated separately here, so it is also the
90  * case for a loop exit where the iteration count is not warp-invariant.
91  *
92  */
93 
94 enum bifrost_flow {
95         /* End-of-shader */
96         BIFROST_FLOW_END = 0,
97 
98         /* Non back-to-back, PC-encoded reconvergence */
99         BIFROST_FLOW_NBTB_PC = 1,
100 
101         /* Non back-to-back, unconditional reconvergence */
102         BIFROST_FLOW_NBTB_UNCONDITIONAL = 2,
103 
104         /* Non back-to-back, no reconvergence */
105         BIFROST_FLOW_NBTB = 3,
106 
107         /* Back-to-back, unconditional reconvergence */
108         BIFROST_FLOW_BTB_UNCONDITIONAL = 4,
109 
110         /* Back-to-back, no reconvergence */
111         BIFROST_FLOW_BTB_NONE = 5,
112 
113         /* Write elision, unconditional reconvergence */
114         BIFROST_FLOW_WE_UNCONDITIONAL = 6,
115 
116         /* Write elision, no reconvergence */
117         BIFROST_FLOW_WE = 7,
118 };
119 
120 enum bifrost_slot {
121         /* 0-5 are general purpose */
122         BIFROST_SLOT_ELDEST_DEPTH = 6,
123         BIFROST_SLOT_ELDEST_COLOUR = 7,
124 };
125 
126 struct bifrost_header {
127         /* Reserved */
128         unsigned zero1 : 5;
129 
130         /* Flush-to-zero mode, leave zero for GL */
131         enum bifrost_ftz flush_to_zero : 2;
132 
133         /* Convert any infinite result of any floating-point operation to the
134          * biggest representable number */
135         unsigned suppress_inf: 1;
136 
137         /* Convert NaN to +0.0 */
138         unsigned suppress_nan : 1;
139 
140         /* Floating-point excception handling mode */
141         enum bifrost_exceptions float_exceptions : 2;
142 
143         /* Enum describing the flow control, which matters for handling
144          * divergence and reconvergence efficiently */
145         enum bifrost_flow flow_control : 3;
146 
147         /* Reserved */
148         unsigned zero2 : 1;
149 
150         /* Terminate discarded threads, rather than continuing execution. Set
151          * for fragment shaders for standard GL behaviour of DISCARD. Also in a
152          * fragment shader, this disables helper invocations, so cannot be used
153          * in a shader that requires derivatives or texture LOD computation */
154         unsigned terminate_discarded_threads : 1;
155 
156         /* If set, the hardware may prefetch the next clause. If false, the
157          * hardware may not. Clear for unconditional branches. */
158         unsigned next_clause_prefetch : 1;
159 
160         /* If set, a barrier will be inserted after the clause waiting for all
161          * message passing instructions to read their staging registers, such
162          * that it is safe for the next clause to write them. */
163         unsigned staging_barrier: 1;
164         unsigned staging_register : 6;
165 
166         /* Slots to wait on and slot to be used for message passing
167          * instructions respectively */
168         unsigned dependency_wait : 8;
169         unsigned dependency_slot : 3;
170 
171         enum bifrost_message_type message_type : 5;
172         enum bifrost_message_type next_message_type : 5;
173 } __attribute__((packed));
174 
175 enum bifrost_packed_src {
176         BIFROST_SRC_PORT0    = 0,
177         BIFROST_SRC_PORT1    = 1,
178         BIFROST_SRC_PORT2    = 2,
179         BIFROST_SRC_STAGE    = 3,
180         BIFROST_SRC_FAU_LO   = 4,
181         BIFROST_SRC_FAU_HI   = 5,
182         BIFROST_SRC_PASS_FMA = 6,
183         BIFROST_SRC_PASS_ADD = 7,
184 };
185 
186 struct bifrost_fma_inst {
187         unsigned src0 : 3;
188         unsigned op   : 20;
189 } __attribute__((packed));
190 
191 struct bifrost_add_inst {
192         unsigned src0 : 3;
193         unsigned op   : 17;
194 } __attribute__((packed));
195 
196 enum branch_bit_size {
197         BR_SIZE_32 = 0,
198         BR_SIZE_16XX = 1,
199         BR_SIZE_16YY = 2,
200         // For the above combinations of bitsize and location, an extra bit is
201         // encoded via comparing the sources. The only possible source of ambiguity
202         // would be if the sources were the same, but then the branch condition
203         // would be always true or always false anyways, so we can ignore it. But
204         // this no longer works when comparing the y component to the x component,
205         // since it's valid to compare the y component of a source against its own
206         // x component. Instead, the extra bit is encoded via an extra bitsize.
207         BR_SIZE_16YX0 = 3,
208         BR_SIZE_16YX1 = 4,
209         BR_SIZE_32_AND_16X = 5,
210         BR_SIZE_32_AND_16Y = 6,
211         // Used for comparisons with zero and always-true, see below. I think this
212         // only works for integer comparisons.
213         BR_SIZE_ZERO = 7,
214 };
215 
216 struct bifrost_regs {
217         unsigned fau_idx : 8;
218         unsigned reg3 : 6;
219         unsigned reg2 : 6;
220         unsigned reg0 : 5;
221         unsigned reg1 : 6;
222         unsigned ctrl : 4;
223 } __attribute__((packed));
224 
225 #define BIFROST_FMTC_CONSTANTS       0b0011
226 #define BIFROST_FMTC_FINAL           0b0111
227 
228 struct bifrost_fmt_constant {
229         unsigned pos : 4;
230         unsigned tag : 4;
231         uint64_t imm_1 : 60;
232         uint64_t imm_2 : 60;
233 } __attribute__((packed));
234 
235 /* Clause formats, encoded in a table */
236 
237 enum bi_clause_subword {
238         /* Literal 3-bit values */
239         BI_CLAUSE_SUBWORD_LITERAL_0 = 0,
240         /* etc */
241         BI_CLAUSE_SUBWORD_LITERAL_7 = 7,
242 
243         /* The value of the corresponding tuple in the corresponding bits */
244         BI_CLAUSE_SUBWORD_TUPLE_0 = 8,
245         /* etc */
246         BI_CLAUSE_SUBWORD_TUPLE_7 = 15,
247 
248         /* Clause header */
249         BI_CLAUSE_SUBWORD_HEADER = 16,
250 
251         /* Leave zero, but semantically distinct from literal 0 */
252         BI_CLAUSE_SUBWORD_RESERVED = 17,
253 
254         /* Embedded constant 0 */
255         BI_CLAUSE_SUBWORD_CONSTANT = 18,
256 
257         /* M bits controlling modifier for the constant */
258         BI_CLAUSE_SUBWORD_M = 19,
259 
260         /* Z bit: 1 to begin encoding constants, 0 to terminate the clause */
261         BI_CLAUSE_SUBWORD_Z = 20,
262 
263         /* Upper 3-bits of a given tuple and zero extended */
264         BI_CLAUSE_SUBWORD_UPPER_0 = 32,
265         /* etc */
266         BI_CLAUSE_SUBWORD_UPPER_7 = BI_CLAUSE_SUBWORD_UPPER_0 + 7,
267 
268         /* Upper 3-bits of two tuples, concatenated and zero-extended */
269         BI_CLAUSE_SUBWORD_UPPER_23 = BI_CLAUSE_SUBWORD_UPPER_0 + 23,
270         BI_CLAUSE_SUBWORD_UPPER_56 = BI_CLAUSE_SUBWORD_UPPER_0 + 56,
271 };
272 
273 #define L(x) (BI_CLAUSE_SUBWORD_LITERAL_0 + x)
274 #define U(x) (BI_CLAUSE_SUBWORD_UPPER_0 + x)
275 #define T(x) (BI_CLAUSE_SUBWORD_TUPLE_0 + x)
276 #define EC   BI_CLAUSE_SUBWORD_CONSTANT
277 #define M    BI_CLAUSE_SUBWORD_M
278 #define Z    BI_CLAUSE_SUBWORD_Z
279 #define H    BI_CLAUSE_SUBWORD_HEADER
280 #define R    BI_CLAUSE_SUBWORD_RESERVED
281 
282 struct bi_clause_format {
283         unsigned format; /* format number */
284         unsigned pos; /* index in the clause */
285         enum bi_clause_subword tag_1; /* 2-bits */
286         enum bi_clause_subword tag_2; /* 3-bits */
287         enum bi_clause_subword tag_3; /* 3-bits */
288         enum bi_clause_subword s0_s3; /* 60 bits */
289         enum bi_clause_subword s4; /* 15 bits */
290         enum bi_clause_subword s5_s6; /* 30 bits */
291         enum bi_clause_subword s7; /* 15 bits */
292 };
293 
294 static const struct bi_clause_format bi_clause_formats[] = {
295         {  0, 0, L(0), L(5), U(0), T(0), T(0), H,    H     },
296         {  0, 0, Z,    L(1), U(0), T(0), T(0), H,    H     },
297         {  1, 1, Z,    L(0), L(3), T(1), T(1), R,    U(1)  },
298         {  2, 1, L(0), L(4), U(1), T(1), T(1), T(2), T(2)  },
299         {  3, 2, Z,    L(0), L(4), EC,   M,    T(2), U(2)  },
300         {  4, 2, L(0), L(0), L(1), T(3), T(3), T(2), U(23) },
301         {  4, 2, Z,    L(0), L(5), T(3), T(3), T(2), U(23) },
302         {  5, 2, L(2), U(3), U(2), T(3), T(3), T(2), EC    },
303         {  6, 3, Z,    L(2), U(4), T(4), T(4), EC,   EC    },
304         {  7, 3, L(1), L(4), U(4), T(4), T(4), T(5), T(5)  },
305         {  8, 4, Z,    L(0), L(6), EC,   M,    T(5), U(5)  },
306         {  9, 4, Z,    L(0), L(7), T(6), T(6), T(5), U(56) },
307         { 10, 4, L(3), U(6), U(5), T(6), T(6), T(5), EC    },
308         { 11, 5, Z,    L(3), U(7), T(7), T(7), EC,   EC    },
309 };
310 
311 #undef L
312 #undef U
313 #undef T
314 #undef EC
315 #undef M
316 #undef Z
317 #undef H
318 #undef R
319 
320 /* 32-bit modes for slots 2/3, as encoded in the register block. Other values
321  * are reserved. First part specifies behaviour of slot 2 (Idle, Read, Write
322  * Full, Write Low, Write High), second part behaviour of slot 3, and the last
323  * part specifies the source for the write (FMA, ADD, or MIX for FMA/ADD).
324  *
325  * IDLE is a special mode disabling both slots, except for the first
326  * instruction in the clause which uses IDLE_1 for the same purpose.
327  *
328  * All fields 0 used as sentinel for reserved encoding, so IDLE(_1) have FMA
329  * set (and ignored) as a placeholder to differentiate from reserved.
330  */
331 enum bifrost_reg_mode {
332         BIFROST_R_WL_FMA  = 1,
333         BIFROST_R_WH_FMA  = 2,
334         BIFROST_R_W_FMA   = 3,
335         BIFROST_R_WL_ADD  = 4,
336         BIFROST_R_WH_ADD  = 5,
337         BIFROST_R_W_ADD   = 6,
338         BIFROST_WL_WL_ADD = 7,
339         BIFROST_WL_WH_ADD = 8,
340         BIFROST_WL_W_ADD  = 9,
341         BIFROST_WH_WL_ADD = 10,
342         BIFROST_WH_WH_ADD = 11,
343         BIFROST_WH_W_ADD  = 12,
344         BIFROST_W_WL_ADD  = 13,
345         BIFROST_W_WH_ADD  = 14,
346         BIFROST_W_W_ADD   = 15,
347         BIFROST_IDLE_1    = 16,
348         BIFROST_I_W_FMA   = 17,
349         BIFROST_I_WL_FMA  = 18,
350         BIFROST_I_WH_FMA  = 19,
351         BIFROST_R_I       = 20,
352         BIFROST_I_W_ADD   = 21,
353         BIFROST_I_WL_ADD  = 22,
354         BIFROST_I_WH_ADD  = 23,
355         BIFROST_WL_WH_MIX = 24,
356         BIFROST_WH_WL_MIX = 26,
357         BIFROST_IDLE      = 27,
358 };
359 
360 enum bifrost_reg_op {
361         BIFROST_OP_IDLE = 0,
362         BIFROST_OP_READ = 1,
363         BIFROST_OP_WRITE = 2,
364         BIFROST_OP_WRITE_LO = 3,
365         BIFROST_OP_WRITE_HI = 4,
366 };
367 
368 struct bifrost_reg_ctrl_23 {
369         enum bifrost_reg_op slot2;
370         enum bifrost_reg_op slot3;
371         bool slot3_fma;
372 };
373 
374 static const struct bifrost_reg_ctrl_23 bifrost_reg_ctrl_lut[32] = {
375         [BIFROST_R_WL_FMA]  = { BIFROST_OP_READ,     BIFROST_OP_WRITE_LO, true },
376         [BIFROST_R_WH_FMA]  = { BIFROST_OP_READ,     BIFROST_OP_WRITE_HI, true },
377         [BIFROST_R_W_FMA]   = { BIFROST_OP_READ,     BIFROST_OP_WRITE,    true },
378         [BIFROST_R_WL_ADD]  = { BIFROST_OP_READ,     BIFROST_OP_WRITE_LO, false },
379         [BIFROST_R_WH_ADD]  = { BIFROST_OP_READ,     BIFROST_OP_WRITE_HI, false },
380         [BIFROST_R_W_ADD]   = { BIFROST_OP_READ,     BIFROST_OP_WRITE,    false },
381         [BIFROST_WL_WL_ADD] = { BIFROST_OP_WRITE_LO, BIFROST_OP_WRITE_LO, false },
382         [BIFROST_WL_WH_ADD] = { BIFROST_OP_WRITE_LO, BIFROST_OP_WRITE_HI, false },
383         [BIFROST_WL_W_ADD]  = { BIFROST_OP_WRITE_LO, BIFROST_OP_WRITE,    false },
384         [BIFROST_WH_WL_ADD] = { BIFROST_OP_WRITE_HI, BIFROST_OP_WRITE_LO, false },
385         [BIFROST_WH_WH_ADD] = { BIFROST_OP_WRITE_HI, BIFROST_OP_WRITE_HI, false },
386         [BIFROST_WH_W_ADD]  = { BIFROST_OP_WRITE_HI, BIFROST_OP_WRITE,    false },
387         [BIFROST_W_WL_ADD]  = { BIFROST_OP_WRITE,    BIFROST_OP_WRITE_LO, false },
388         [BIFROST_W_WH_ADD]  = { BIFROST_OP_WRITE,    BIFROST_OP_WRITE_HI, false },
389         [BIFROST_W_W_ADD]   = { BIFROST_OP_WRITE,    BIFROST_OP_WRITE,    false },
390         [BIFROST_IDLE_1]    = { BIFROST_OP_IDLE,     BIFROST_OP_IDLE,     true },
391         [BIFROST_I_W_FMA]   = { BIFROST_OP_IDLE,     BIFROST_OP_WRITE,    true },
392         [BIFROST_I_WL_FMA]  = { BIFROST_OP_IDLE,     BIFROST_OP_WRITE_LO, true },
393         [BIFROST_I_WH_FMA]  = { BIFROST_OP_IDLE,     BIFROST_OP_WRITE_HI, true },
394         [BIFROST_R_I]       = { BIFROST_OP_READ,     BIFROST_OP_IDLE,     false },
395         [BIFROST_I_W_ADD]   = { BIFROST_OP_IDLE,     BIFROST_OP_WRITE,    false },
396         [BIFROST_I_WL_ADD]  = { BIFROST_OP_IDLE,     BIFROST_OP_WRITE_LO, false },
397         [BIFROST_I_WH_ADD]  = { BIFROST_OP_IDLE,     BIFROST_OP_WRITE_HI, false },
398         [BIFROST_WL_WH_MIX] = { BIFROST_OP_WRITE_LO, BIFROST_OP_WRITE_HI, false },
399         [BIFROST_WH_WL_MIX] = { BIFROST_OP_WRITE_HI, BIFROST_OP_WRITE_LO, false },
400         [BIFROST_IDLE]      = { BIFROST_OP_IDLE,     BIFROST_OP_IDLE,     true },
401 };
402 
403 /* Texture operator descriptors in various states. Usually packed in the
404  * compiler and stored as a constant */
405 
406 enum bifrost_index {
407         /* Both texture/sampler index immediate */
408         BIFROST_INDEX_IMMEDIATE_SHARED = 0,
409 
410         /* Sampler index immediate, texture index from staging */
411         BIFROST_INDEX_IMMEDIATE_SAMPLER = 1,
412 
413         /* Texture index immediate, sampler index from staging */
414         BIFROST_INDEX_IMMEDIATE_TEXTURE = 2,
415 
416         /* Both indices from (separate) staging registers */
417         BIFROST_INDEX_REGISTER = 3,
418 };
419 
420 enum bifrost_tex_op {
421         /* Given explicit derivatives, compute a gradient descriptor */
422         BIFROST_TEX_OP_GRDESC_DER = 4,
423 
424         /* Given implicit derivatives (texture coordinates in a fragment
425          * shader), compute a gradient descriptor */
426         BIFROST_TEX_OP_GRDESC = 5,
427 
428         /* Fetch a texel. Takes a staging register with LOD level / face index
429          * packed 16:16 */
430         BIFROST_TEX_OP_FETCH = 6,
431 
432         /* Filtered texture */
433         BIFROST_TEX_OP_TEX = 7,
434 };
435 
436 enum bifrost_lod_mode {
437         /* Takes two staging registers forming a 64-bit gradient descriptor
438          * (computed by a previous GRDESC or GRDESC_DER operation) */
439         BIFROST_LOD_MODE_GRDESC = 3,
440 
441         /* Take a staging register with 8:8 fixed-point in bottom 16-bits
442          * specifying an explicit LOD */
443         BIFROST_LOD_MODE_EXPLICIT = 4,
444 
445         /* Takes a staging register with bottom 16-bits as 8:8 fixed-point LOD
446          * bias and top 16-bit as 8:8 fixed-point lower bound (generally left
447          * zero), added and clamped to a computed LOD */
448         BIFROST_LOD_MODE_BIAS = 5,
449 
450         /* Set LOD to zero */
451         BIFROST_LOD_MODE_ZERO = 6,
452 
453         /* Compute LOD */
454         BIFROST_LOD_MODE_COMPUTE = 7,
455 };
456 
457 enum bifrost_texture_format {
458         /* 16-bit floating point, with optional clamping */
459         BIFROST_TEXTURE_FORMAT_F16 = 0,
460         BIFROST_TEXTURE_FORMAT_F16_POS = 1,
461         BIFROST_TEXTURE_FORMAT_F16_PM1 = 2,
462         BIFROST_TEXTURE_FORMAT_F16_1 = 3,
463 
464         /* 32-bit floating point, with optional clamping */
465         BIFROST_TEXTURE_FORMAT_F32 = 4,
466         BIFROST_TEXTURE_FORMAT_F32_POS = 5,
467         BIFROST_TEXTURE_FORMAT_F32_PM1 = 6,
468         BIFROST_TEXTURE_FORMAT_F32_1 = 7,
469 };
470 
471 enum bifrost_texture_format_full {
472         /* Transclude bifrost_texture_format from above */
473 
474         /* Integers, unclamped */
475         BIFROST_TEXTURE_FORMAT_U16 = 12,
476         BIFROST_TEXTURE_FORMAT_S16 = 13,
477         BIFROST_TEXTURE_FORMAT_U32 = 14,
478         BIFROST_TEXTURE_FORMAT_S32 = 15,
479 };
480 
481 enum bifrost_texture_fetch {
482         /* Default texelFetch */
483         BIFROST_TEXTURE_FETCH_TEXEL = 1,
484 
485         /* Deprecated, fetches 4x U32 of a U8 x 4 texture. Do not use. */
486         BIFROST_TEXTURE_FETCH_GATHER4_RGBA = 3,
487 
488         /* Gathers */
489         BIFROST_TEXTURE_FETCH_GATHER4_R = 4,
490         BIFROST_TEXTURE_FETCH_GATHER4_G = 5,
491         BIFROST_TEXTURE_FETCH_GATHER4_B = 6,
492         BIFROST_TEXTURE_FETCH_GATHER4_A = 7
493 };
494 
495 struct bifrost_texture_operation {
496         /* If immediate_indices is set:
497          *     - immediate sampler index
498          *     - index used as texture index
499          * Otherwise:
500          *      - bifrost_single_index in lower 2 bits
501          *      - 0x3 in upper 2 bits (single-texturing)
502          */
503         unsigned sampler_index_or_mode : 4;
504         unsigned index : 7;
505         bool immediate_indices : 1;
506         enum bifrost_tex_op op : 3;
507 
508         /* If set for TEX/FETCH, loads texel offsets and multisample index from
509          * a staging register containing offset_x:offset_y:offset_z:ms_index
510          * packed 8:8:8:8. Offsets must be in [-31, +31]. If set for
511          * GRDESC(_DER), disable LOD bias. */
512         bool offset_or_bias_disable : 1;
513 
514         /* If set for TEX/FETCH, loads fp32 shadow comparison value from a
515          * staging register. Implies fetch_component = gather4_r. If set for
516          * GRDESC(_DER), disables LOD clamping. */
517         bool shadow_or_clamp_disable : 1;
518 
519         /* If set, loads an uint32 array index from a staging register. */
520         bool array : 1;
521 
522         /* Texture dimension, or 0 for a cubemap */
523         unsigned dimension : 2;
524 
525         /* Method to compute LOD value or for a FETCH, the
526          * bifrost_texture_fetch component specification */
527         enum bifrost_lod_mode lod_or_fetch : 3;
528 
529         /* Reserved */
530         unsigned zero : 1;
531 
532         /* Register format for the result */
533         enum bifrost_texture_format_full format : 4;
534 
535         /* Write mask for the result */
536         unsigned mask : 4;
537 } __attribute__((packed));
538 
539 #define BIFROST_MEGA_SAMPLE 128
540 #define BIFROST_ALL_SAMPLES 255
541 #define BIFROST_CURRENT_PIXEL 255
542 
543 struct bifrost_pixel_indices {
544         unsigned sample : 8;
545         unsigned rt : 8;
546         unsigned x : 8;
547         unsigned y : 8;
548 } __attribute__((packed));
549 
550 enum bi_constmod {
551         BI_CONSTMOD_NONE,
552         BI_CONSTMOD_PC_LO,
553         BI_CONSTMOD_PC_HI,
554         BI_CONSTMOD_PC_LO_HI
555 };
556 
557 struct bi_constants {
558         /* Raw constant values */
559         uint64_t raw[6];
560 
561         /* Associated modifier derived from M values */
562         enum bi_constmod mods[6];
563 };
564 
565 /* FAU selectors for constants are out-of-order, construct the top bits
566  * here given a embedded constant index in a clause */
567 
568 static inline unsigned
bi_constant_field(unsigned idx)569 bi_constant_field(unsigned idx)
570 {
571         const unsigned values[] = {
572                 4, 5, 6, 7, 2, 3
573         };
574 
575         assert(idx <= 5);
576         return values[idx] << 4;
577 }
578 
579 #endif
580