bifrost.h revision 7ec681f3
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
43extern int bifrost_debug;
44
45enum 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
64enum bifrost_ftz {
65        BIFROST_FTZ_DISABLE = 0,
66        BIFROST_FTZ_DX11 = 1,
67        BIFROST_FTZ_ALWAYS = 2,
68        BIFROST_FTZ_ABRUPT = 3
69};
70
71enum 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
94enum 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
120enum bifrost_slot {
121        /* 0-5 are general purpose */
122        BIFROST_SLOT_ELDEST_DEPTH = 6,
123        BIFROST_SLOT_ELDEST_COLOUR = 7,
124};
125
126struct 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
175enum 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
186struct bifrost_fma_inst {
187        unsigned src0 : 3;
188        unsigned op   : 20;
189} __attribute__((packed));
190
191struct bifrost_add_inst {
192        unsigned src0 : 3;
193        unsigned op   : 17;
194} __attribute__((packed));
195
196enum 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
216struct 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
228struct 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
237enum 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
282struct 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
294static 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 */
331enum 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
360enum 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
368struct bifrost_reg_ctrl_23 {
369        enum bifrost_reg_op slot2;
370        enum bifrost_reg_op slot3;
371        bool slot3_fma;
372};
373
374static 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
406enum 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
420enum 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
436enum 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
457enum 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
471enum 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
481enum 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
495struct 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
543struct bifrost_pixel_indices {
544        unsigned sample : 8;
545        unsigned rt : 8;
546        unsigned x : 8;
547        unsigned y : 8;
548} __attribute__((packed));
549
550enum bi_constmod {
551        BI_CONSTMOD_NONE,
552        BI_CONSTMOD_PC_LO,
553        BI_CONSTMOD_PC_HI,
554        BI_CONSTMOD_PC_LO_HI
555};
556
557struct 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
568static inline unsigned
569bi_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