c296447b5c50294b082df5387e3cc7d87d22e4cb
1 TGSI
2 ====
4 TGSI, Tungsten Graphics Shader Infrastructure, is an intermediate language
6 an important part of the API. TGSI is the only intermediate representation
7 used by all drivers.
9 Basics
10 ------
12 All TGSI instructions, known as *opcodes*, operate on arbitrary-precision
13 floating-point four-component vectors. An opcode may have up to one
14 destination register, known as *dst*, and between zero and three source
15 registers, called *src0* through *src2*, or simply *src* if there is only
16 one.
18 Some instructions, like :opcode:I2F, permit re-interpretation of vector
19 components as integers. Other instructions permit using registers as
20 two-component vectors with double precision; see :ref:doubleopcodes.
22 When an instruction has a scalar result, the result is usually copied into
23 each of the components of *dst*. When this happens, the result is said to be
24 *replicated* to *dst*. :opcode:RCP is one such instruction.
26 Modifiers
27 ^^^^^^^^^^^^^^^
29 TGSI supports modifiers on inputs (as well as saturate modifier on instructions).
31 For inputs which have a floating point type, both absolute value and negation
32 modifiers are supported (with absolute value being applied first).
33 TGSI_OPCODE_MOV is considered to have float input type for applying modifiers.
35 For inputs which have signed or unsigned type only the negate modifier is
36 supported.
38 Instruction Set
39 ---------------
41 Core ISA
42 ^^^^^^^^^^^^^^^^^^^^^^^^^
44 These opcodes are guaranteed to be available regardless of the driver being
45 used.
49 .. math::
51 dst.x = (int) \lfloor src.x\rfloor
53 dst.y = (int) \lfloor src.y\rfloor
55 dst.z = (int) \lfloor src.z\rfloor
57 dst.w = (int) \lfloor src.w\rfloor
60 .. opcode:: MOV - Move
62 .. math::
64 dst.x = src.x
66 dst.y = src.y
68 dst.z = src.z
70 dst.w = src.w
73 .. opcode:: LIT - Light Coefficients
75 .. math::
77 dst.x &= 1 \\
78 dst.y &= max(src.x, 0) \\
79 dst.z &= (src.x > 0) ? max(src.y, 0)^{clamp(src.w, -128, 128))} : 0 \\
80 dst.w &= 1
83 .. opcode:: RCP - Reciprocal
85 This instruction replicates its result.
87 .. math::
89 dst = \frac{1}{src.x}
92 .. opcode:: RSQ - Reciprocal Square Root
94 This instruction replicates its result. The results are undefined for src <= 0.
96 .. math::
98 dst = \frac{1}{\sqrt{src.x}}
101 .. opcode:: SQRT - Square Root
103 This instruction replicates its result. The results are undefined for src < 0.
105 .. math::
107 dst = {\sqrt{src.x}}
110 .. opcode:: EXP - Approximate Exponential Base 2
112 .. math::
114 dst.x &= 2^{\lfloor src.x\rfloor} \\
115 dst.y &= src.x - \lfloor src.x\rfloor \\
116 dst.z &= 2^{src.x} \\
117 dst.w &= 1
120 .. opcode:: LOG - Approximate Logarithm Base 2
122 .. math::
124 dst.x &= \lfloor\log_2{|src.x|}\rfloor \\
125 dst.y &= \frac{|src.x|}{2^{\lfloor\log_2{|src.x|}\rfloor}} \\
126 dst.z &= \log_2{|src.x|} \\
127 dst.w &= 1
130 .. opcode:: MUL - Multiply
132 .. math::
134 dst.x = src0.x \times src1.x
136 dst.y = src0.y \times src1.y
138 dst.z = src0.z \times src1.z
140 dst.w = src0.w \times src1.w
145 .. math::
147 dst.x = src0.x + src1.x
149 dst.y = src0.y + src1.y
151 dst.z = src0.z + src1.z
153 dst.w = src0.w + src1.w
156 .. opcode:: DP3 - 3-component Dot Product
158 This instruction replicates its result.
160 .. math::
162 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
165 .. opcode:: DP4 - 4-component Dot Product
167 This instruction replicates its result.
169 .. math::
171 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
174 .. opcode:: DST - Distance Vector
176 .. math::
178 dst.x &= 1\\
179 dst.y &= src0.y \times src1.y\\
180 dst.z &= src0.z\\
181 dst.w &= src1.w
184 .. opcode:: MIN - Minimum
186 .. math::
188 dst.x = min(src0.x, src1.x)
190 dst.y = min(src0.y, src1.y)
192 dst.z = min(src0.z, src1.z)
194 dst.w = min(src0.w, src1.w)
197 .. opcode:: MAX - Maximum
199 .. math::
201 dst.x = max(src0.x, src1.x)
203 dst.y = max(src0.y, src1.y)
205 dst.z = max(src0.z, src1.z)
207 dst.w = max(src0.w, src1.w)
210 .. opcode:: SLT - Set On Less Than
212 .. math::
214 dst.x = (src0.x < src1.x) ? 1.0F : 0.0F
216 dst.y = (src0.y < src1.y) ? 1.0F : 0.0F
218 dst.z = (src0.z < src1.z) ? 1.0F : 0.0F
220 dst.w = (src0.w < src1.w) ? 1.0F : 0.0F
223 .. opcode:: SGE - Set On Greater Equal Than
225 .. math::
227 dst.x = (src0.x >= src1.x) ? 1.0F : 0.0F
229 dst.y = (src0.y >= src1.y) ? 1.0F : 0.0F
231 dst.z = (src0.z >= src1.z) ? 1.0F : 0.0F
233 dst.w = (src0.w >= src1.w) ? 1.0F : 0.0F
238 .. math::
240 dst.x = src0.x \times src1.x + src2.x
242 dst.y = src0.y \times src1.y + src2.y
244 dst.z = src0.z \times src1.z + src2.z
246 dst.w = src0.w \times src1.w + src2.w
249 .. opcode:: LRP - Linear Interpolate
251 .. math::
253 dst.x = src0.x \times src1.x + (1 - src0.x) \times src2.x
255 dst.y = src0.y \times src1.y + (1 - src0.y) \times src2.y
257 dst.z = src0.z \times src1.z + (1 - src0.z) \times src2.z
259 dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
262 .. opcode:: FMA - Fused Multiply-Add
264 Perform a * b + c with no intermediate rounding step.
266 .. math::
268 dst.x = src0.x \times src1.x + src2.x
270 dst.y = src0.y \times src1.y + src2.y
272 dst.z = src0.z \times src1.z + src2.z
274 dst.w = src0.w \times src1.w + src2.w
277 .. opcode:: DP2A - 2-component Dot Product And Add
279 .. math::
281 dst.x = src0.x \times src1.x + src0.y \times src1.y + src2.x
283 dst.y = src0.x \times src1.x + src0.y \times src1.y + src2.x
285 dst.z = src0.x \times src1.x + src0.y \times src1.y + src2.x
287 dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x
290 .. opcode:: FRC - Fraction
292 .. math::
294 dst.x = src.x - \lfloor src.x\rfloor
296 dst.y = src.y - \lfloor src.y\rfloor
298 dst.z = src.z - \lfloor src.z\rfloor
300 dst.w = src.w - \lfloor src.w\rfloor
303 .. opcode:: FLR - Floor
305 .. math::
307 dst.x = \lfloor src.x\rfloor
309 dst.y = \lfloor src.y\rfloor
311 dst.z = \lfloor src.z\rfloor
313 dst.w = \lfloor src.w\rfloor
316 .. opcode:: ROUND - Round
318 .. math::
320 dst.x = round(src.x)
322 dst.y = round(src.y)
324 dst.z = round(src.z)
326 dst.w = round(src.w)
329 .. opcode:: EX2 - Exponential Base 2
331 This instruction replicates its result.
333 .. math::
335 dst = 2^{src.x}
338 .. opcode:: LG2 - Logarithm Base 2
340 This instruction replicates its result.
342 .. math::
344 dst = \log_2{src.x}
347 .. opcode:: POW - Power
349 This instruction replicates its result.
351 .. math::
353 dst = src0.x^{src1.x}
355 .. opcode:: XPD - Cross Product
357 .. math::
359 dst.x = src0.y \times src1.z - src1.y \times src0.z
361 dst.y = src0.z \times src1.x - src1.z \times src0.x
363 dst.z = src0.x \times src1.y - src1.x \times src0.y
365 dst.w = 1
368 .. opcode:: DPH - Homogeneous Dot Product
370 This instruction replicates its result.
372 .. math::
374 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
377 .. opcode:: COS - Cosine
379 This instruction replicates its result.
381 .. math::
383 dst = \cos{src.x}
386 .. opcode:: DDX, DDX_FINE - Derivative Relative To X
388 The fine variant is only used when PIPE_CAP_TGSI_FS_FINE_DERIVATIVE is
389 advertised. When it is, the fine version guarantees one derivative per row
390 while DDX is allowed to be the same for the entire 2x2 quad.
392 .. math::
394 dst.x = partialx(src.x)
396 dst.y = partialx(src.y)
398 dst.z = partialx(src.z)
400 dst.w = partialx(src.w)
403 .. opcode:: DDY, DDY_FINE - Derivative Relative To Y
405 The fine variant is only used when PIPE_CAP_TGSI_FS_FINE_DERIVATIVE is
406 advertised. When it is, the fine version guarantees one derivative per column
407 while DDY is allowed to be the same for the entire 2x2 quad.
409 .. math::
411 dst.x = partialy(src.x)
413 dst.y = partialy(src.y)
415 dst.z = partialy(src.z)
417 dst.w = partialy(src.w)
420 .. opcode:: PK2H - Pack Two 16-bit Floats
422 This instruction replicates its result.
424 .. math::
426 dst = f32\_to\_f16(src.x) | f32\_to\_f16(src.y) << 16
429 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
431 TBD
434 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
436 TBD
439 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
441 TBD
444 .. opcode:: SEQ - Set On Equal
446 .. math::
448 dst.x = (src0.x == src1.x) ? 1.0F : 0.0F
450 dst.y = (src0.y == src1.y) ? 1.0F : 0.0F
452 dst.z = (src0.z == src1.z) ? 1.0F : 0.0F
454 dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
457 .. opcode:: SGT - Set On Greater Than
459 .. math::
461 dst.x = (src0.x > src1.x) ? 1.0F : 0.0F
463 dst.y = (src0.y > src1.y) ? 1.0F : 0.0F
465 dst.z = (src0.z > src1.z) ? 1.0F : 0.0F
467 dst.w = (src0.w > src1.w) ? 1.0F : 0.0F
470 .. opcode:: SIN - Sine
472 This instruction replicates its result.
474 .. math::
476 dst = \sin{src.x}
479 .. opcode:: SLE - Set On Less Equal Than
481 .. math::
483 dst.x = (src0.x <= src1.x) ? 1.0F : 0.0F
485 dst.y = (src0.y <= src1.y) ? 1.0F : 0.0F
487 dst.z = (src0.z <= src1.z) ? 1.0F : 0.0F
489 dst.w = (src0.w <= src1.w) ? 1.0F : 0.0F
492 .. opcode:: SNE - Set On Not Equal
494 .. math::
496 dst.x = (src0.x != src1.x) ? 1.0F : 0.0F
498 dst.y = (src0.y != src1.y) ? 1.0F : 0.0F
500 dst.z = (src0.z != src1.z) ? 1.0F : 0.0F
502 dst.w = (src0.w != src1.w) ? 1.0F : 0.0F
505 .. opcode:: TEX - Texture Lookup
507 for array textures src0.y contains the slice for 1D,
508 and src0.z contain the slice for 2D.
510 for shadow textures with no arrays (and not cube map),
511 src0.z contains the reference value.
513 for shadow textures with arrays, src0.z contains
514 the reference value for 1D arrays, and src0.w contains
515 the reference value for 2D arrays and cube maps.
517 for cube map array shadow textures, the reference value
518 cannot be passed in src0.w, and TEX2 must be used instead.
520 .. math::
522 coord = src0
524 shadow_ref = src0.z or src0.w (optional)
526 unit = src1
528 dst = texture\_sample(unit, coord, shadow_ref)
531 .. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only)
533 this is the same as TEX, but uses another reg to encode the
534 reference value.
536 .. math::
538 coord = src0
542 unit = src2
544 dst = texture\_sample(unit, coord, shadow_ref)
549 .. opcode:: TXD - Texture Lookup with Derivatives
551 .. math::
553 coord = src0
555 ddx = src1
557 ddy = src2
559 unit = src3
561 dst = texture\_sample\_deriv(unit, coord, ddx, ddy)
564 .. opcode:: TXP - Projective Texture Lookup
566 .. math::
568 coord.x = src0.x / src0.w
570 coord.y = src0.y / src0.w
572 coord.z = src0.z / src0.w
574 coord.w = src0.w
576 unit = src1
578 dst = texture\_sample(unit, coord)
581 .. opcode:: UP2H - Unpack Two 16-Bit Floats
583 .. math::
585 dst.x = f16\_to\_f32(src0.x \& 0xffff)
587 dst.y = f16\_to\_f32(src0.x >> 16)
589 dst.z = f16\_to\_f32(src0.x \& 0xffff)
591 dst.w = f16\_to\_f32(src0.x >> 16)
593 .. note::
595 Considered for removal.
597 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
599 TBD
601 .. note::
603 Considered for removal.
605 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
607 TBD
609 .. note::
611 Considered for removal.
613 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
615 TBD
617 .. note::
619 Considered for removal.
624 .. math::
626 dst.x = (int) round(src.x)
628 dst.y = (int) round(src.y)
630 dst.z = (int) round(src.z)
632 dst.w = (int) round(src.w)
635 .. opcode:: SSG - Set Sign
637 .. math::
639 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
641 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
643 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
645 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
648 .. opcode:: CMP - Compare
650 .. math::
652 dst.x = (src0.x < 0) ? src1.x : src2.x
654 dst.y = (src0.y < 0) ? src1.y : src2.y
656 dst.z = (src0.z < 0) ? src1.z : src2.z
658 dst.w = (src0.w < 0) ? src1.w : src2.w
661 .. opcode:: KILL_IF - Conditional Discard
665 .. math::
667 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
669 endif
672 .. opcode:: KILL - Discard
677 .. opcode:: SCS - Sine Cosine
679 .. math::
681 dst.x = \cos{src.x}
683 dst.y = \sin{src.x}
685 dst.z = 0
687 dst.w = 1
690 .. opcode:: TXB - Texture Lookup With Bias
692 for cube map array textures and shadow cube maps, the bias value
693 cannot be passed in src0.w, and TXB2 must be used instead.
695 if the target is a shadow texture, the reference value is always
696 in src.z (this prevents shadow 3d and shadow 2d arrays from
697 using this instruction, but this is not needed).
699 .. math::
701 coord.x = src0.x
703 coord.y = src0.y
705 coord.z = src0.z
707 coord.w = none
709 bias = src0.w
711 unit = src1
713 dst = texture\_sample(unit, coord, bias)
716 .. opcode:: TXB2 - Texture Lookup With Bias (some cube maps only)
718 this is the same as TXB, but uses another reg to encode the
719 lod bias value for cube map arrays and shadow cube maps.
721 this encoding too, but this is not legal.
723 shadow cube map arrays are neither possible nor required.
725 .. math::
727 coord = src0
729 bias = src1.x
731 unit = src2
733 dst = texture\_sample(unit, coord, bias)
736 .. opcode:: DIV - Divide
738 .. math::
740 dst.x = \frac{src0.x}{src1.x}
742 dst.y = \frac{src0.y}{src1.y}
744 dst.z = \frac{src0.z}{src1.z}
746 dst.w = \frac{src0.w}{src1.w}
749 .. opcode:: DP2 - 2-component Dot Product
751 This instruction replicates its result.
753 .. math::
755 dst = src0.x \times src1.x + src0.y \times src1.y
758 .. opcode:: TXL - Texture Lookup With explicit LOD
760 for cube map array textures, the explicit lod value
761 cannot be passed in src0.w, and TXL2 must be used instead.
763 if the target is a shadow texture, the reference value is always
764 in src.z (this prevents shadow 3d / 2d array / cube targets from
765 using this instruction, but this is not needed).
767 .. math::
769 coord.x = src0.x
771 coord.y = src0.y
773 coord.z = src0.z
775 coord.w = none
777 lod = src0.w
779 unit = src1
781 dst = texture\_sample(unit, coord, lod)
784 .. opcode:: TXL2 - Texture Lookup With explicit LOD (for cube map arrays only)
786 this is the same as TXL, but uses another reg to encode the
787 explicit lod value.
788 Presumably shadow 3d / 2d array / cube targets could use
789 this encoding too, but this is not legal.
791 shadow cube map arrays are neither possible nor required.
793 .. math::
795 coord = src0
797 lod = src1.x
799 unit = src2
801 dst = texture\_sample(unit, coord, lod)
804 .. opcode:: PUSHA - Push Address Register On Stack
806 push(src.x)
807 push(src.y)
808 push(src.z)
809 push(src.w)
811 .. note::
813 Considered for cleanup.
815 .. note::
817 Considered for removal.
819 .. opcode:: POPA - Pop Address Register From Stack
821 dst.w = pop()
822 dst.z = pop()
823 dst.y = pop()
824 dst.x = pop()
826 .. note::
828 Considered for cleanup.
830 .. note::
832 Considered for removal.
835 .. opcode:: CALLNZ - Subroutine Call If Not Zero
837 TBD
839 .. note::
841 Considered for cleanup.
843 .. note::
845 Considered for removal.
848 Compute ISA
849 ^^^^^^^^^^^^^^^^^^^^^^^^
851 These opcodes are primarily provided for special-use computational shaders.
852 Support for these opcodes indicated by a special pipe capability bit (TBD).
854 XXX doesn't look like most of the opcodes really belong here.
856 .. opcode:: CEIL - Ceiling
858 .. math::
860 dst.x = \lceil src.x\rceil
862 dst.y = \lceil src.y\rceil
864 dst.z = \lceil src.z\rceil
866 dst.w = \lceil src.w\rceil
869 .. opcode:: TRUNC - Truncate
871 .. math::
873 dst.x = trunc(src.x)
875 dst.y = trunc(src.y)
877 dst.z = trunc(src.z)
879 dst.w = trunc(src.w)
882 .. opcode:: MOD - Modulus
884 .. math::
886 dst.x = src0.x \bmod src1.x
888 dst.y = src0.y \bmod src1.y
890 dst.z = src0.z \bmod src1.z
892 dst.w = src0.w \bmod src1.w
897 Moves the contents of the source register, assumed to be an integer, into the
898 destination register, which is assumed to be an address (ADDR) register.
901 .. opcode:: SAD - Sum Of Absolute Differences
903 .. math::
905 dst.x = |src0.x - src1.x| + src2.x
907 dst.y = |src0.y - src1.y| + src2.y
909 dst.z = |src0.z - src1.z| + src2.z
911 dst.w = |src0.w - src1.w| + src2.w
914 .. opcode:: TXF - Texel Fetch
916 As per NV_gpu_shader4, extract a single texel from a specified texture
917 image. The source sampler may not be a CUBE or SHADOW. src 0 is a
918 four-component signed integer vector used to identify the single texel
919 accessed. 3 components + level. Just like texture instructions, an optional
920 offset vector is provided, which is subject to various driver restrictions
921 (regarding range, source of offsets).
922 TXF(uint_vec coord, int_vec offset).
925 .. opcode:: TXQ - Texture Size Query
927 As per NV_gpu_program4, retrieve the dimensions of the texture depending on
928 the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
929 depth), 1D array (width, layers), 2D array (width, height, layers).
930 Also return the number of accessible levels (last_level - first_level + 1)
931 in W.
933 For components which don't return a resource dimension, their value
934 is undefined.
936 .. math::
938 lod = src0.x
940 dst.x = texture\_width(unit, lod)
942 dst.y = texture\_height(unit, lod)
944 dst.z = texture\_depth(unit, lod)
946 dst.w = texture\_levels(unit)
949 .. opcode:: TXQS - Texture Samples Query
951 This retrieves the number of samples in the texture, and stores it
952 into the x component. The other components are undefined.
954 .. math::
956 dst.x = texture\_samples(unit)
959 .. opcode:: TG4 - Texture Gather
961 As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
962 filtering operation and packs them into a single register. Only works with
963 2D, 2D array, cubemaps, and cubemaps arrays. For 2D textures, only the
964 addressing modes of the sampler and the top level of any mip pyramid are
965 used. Set W to zero. It behaves like the TEX instruction, but a filtered
966 sample is not generated. The four samples that contribute to filtering are
967 placed into xyzw in clockwise order, starting with the (u,v) texture
968 coordinate delta at the following locations (-, +), (+, +), (+, -), (-, -),
969 where the magnitude of the deltas are half a texel.
971 PIPE_CAP_TEXTURE_SM5 enhances this instruction to support shadow per-sample
972 depth compares, single component selection, and a non-constant offset. It
973 doesn't allow support for the GL independent offset to get i0,j0. This would
974 require another CAP is hw can do it natively. For now we lower that before
975 TGSI.
977 .. math::
979 coord = src0
981 component = src1
983 dst = texture\_gather4 (unit, coord, component)
985 (with SM5 - cube array shadow)
987 .. math::
989 coord = src0
991 compare = src1
993 dst = texture\_gather (uint, coord, compare)
995 .. opcode:: LODQ - level of detail query
997 Compute the LOD information that the texture pipe would use to access the
998 texture. The Y component contains the computed LOD lambda_prime. The X
999 component contains the LOD that will be accessed, based on min/max lod's
1000 and mipmap filters.
1002 .. math::
1004 coord = src0
1006 dst.xy = lodq(uint, coord);
1008 Integer ISA
1009 ^^^^^^^^^^^^^^^^^^^^^^^^
1010 These opcodes are used for integer operations.
1011 Support for these opcodes indicated by PIPE_SHADER_CAP_INTEGERS (all of them?)
1014 .. opcode:: I2F - Signed Integer To Float
1016 Rounding is unspecified (round to nearest even suggested).
1018 .. math::
1020 dst.x = (float) src.x
1022 dst.y = (float) src.y
1024 dst.z = (float) src.z
1026 dst.w = (float) src.w
1029 .. opcode:: U2F - Unsigned Integer To Float
1031 Rounding is unspecified (round to nearest even suggested).
1033 .. math::
1035 dst.x = (float) src.x
1037 dst.y = (float) src.y
1039 dst.z = (float) src.z
1041 dst.w = (float) src.w
1044 .. opcode:: F2I - Float to Signed Integer
1046 Rounding is towards zero (truncate).
1047 Values outside signed range (including NaNs) produce undefined results.
1049 .. math::
1051 dst.x = (int) src.x
1053 dst.y = (int) src.y
1055 dst.z = (int) src.z
1057 dst.w = (int) src.w
1060 .. opcode:: F2U - Float to Unsigned Integer
1062 Rounding is towards zero (truncate).
1063 Values outside unsigned range (including NaNs) produce undefined results.
1065 .. math::
1067 dst.x = (unsigned) src.x
1069 dst.y = (unsigned) src.y
1071 dst.z = (unsigned) src.z
1073 dst.w = (unsigned) src.w
1078 This instruction works the same for signed and unsigned integers.
1079 The low 32bit of the result is returned.
1081 .. math::
1083 dst.x = src0.x + src1.x
1085 dst.y = src0.y + src1.y
1087 dst.z = src0.z + src1.z
1089 dst.w = src0.w + src1.w
1094 This instruction works the same for signed and unsigned integers.
1095 The multiplication returns the low 32bit (as does the result itself).
1097 .. math::
1099 dst.x = src0.x \times src1.x + src2.x
1101 dst.y = src0.y \times src1.y + src2.y
1103 dst.z = src0.z \times src1.z + src2.z
1105 dst.w = src0.w \times src1.w + src2.w
1108 .. opcode:: UMUL - Integer Multiply
1110 This instruction works the same for signed and unsigned integers.
1111 The low 32bit of the result is returned.
1113 .. math::
1115 dst.x = src0.x \times src1.x
1117 dst.y = src0.y \times src1.y
1119 dst.z = src0.z \times src1.z
1121 dst.w = src0.w \times src1.w
1124 .. opcode:: IMUL_HI - Signed Integer Multiply High Bits
1126 The high 32bits of the multiplication of 2 signed integers are returned.
1128 .. math::
1130 dst.x = (src0.x \times src1.x) >> 32
1132 dst.y = (src0.y \times src1.y) >> 32
1134 dst.z = (src0.z \times src1.z) >> 32
1136 dst.w = (src0.w \times src1.w) >> 32
1139 .. opcode:: UMUL_HI - Unsigned Integer Multiply High Bits
1141 The high 32bits of the multiplication of 2 unsigned integers are returned.
1143 .. math::
1145 dst.x = (src0.x \times src1.x) >> 32
1147 dst.y = (src0.y \times src1.y) >> 32
1149 dst.z = (src0.z \times src1.z) >> 32
1151 dst.w = (src0.w \times src1.w) >> 32
1154 .. opcode:: IDIV - Signed Integer Division
1156 TBD: behavior for division by zero.
1158 .. math::
1160 dst.x = src0.x \ src1.x
1162 dst.y = src0.y \ src1.y
1164 dst.z = src0.z \ src1.z
1166 dst.w = src0.w \ src1.w
1169 .. opcode:: UDIV - Unsigned Integer Division
1171 For division by zero, 0xffffffff is returned.
1173 .. math::
1175 dst.x = src0.x \ src1.x
1177 dst.y = src0.y \ src1.y
1179 dst.z = src0.z \ src1.z
1181 dst.w = src0.w \ src1.w
1184 .. opcode:: UMOD - Unsigned Integer Remainder
1186 If second arg is zero, 0xffffffff is returned.
1188 .. math::
1190 dst.x = src0.x \ src1.x
1192 dst.y = src0.y \ src1.y
1194 dst.z = src0.z \ src1.z
1196 dst.w = src0.w \ src1.w
1199 .. opcode:: NOT - Bitwise Not
1201 .. math::
1203 dst.x = \sim src.x
1205 dst.y = \sim src.y
1207 dst.z = \sim src.z
1209 dst.w = \sim src.w
1212 .. opcode:: AND - Bitwise And
1214 .. math::
1216 dst.x = src0.x \& src1.x
1218 dst.y = src0.y \& src1.y
1220 dst.z = src0.z \& src1.z
1222 dst.w = src0.w \& src1.w
1225 .. opcode:: OR - Bitwise Or
1227 .. math::
1229 dst.x = src0.x | src1.x
1231 dst.y = src0.y | src1.y
1233 dst.z = src0.z | src1.z
1235 dst.w = src0.w | src1.w
1238 .. opcode:: XOR - Bitwise Xor
1240 .. math::
1242 dst.x = src0.x \oplus src1.x
1244 dst.y = src0.y \oplus src1.y
1246 dst.z = src0.z \oplus src1.z
1248 dst.w = src0.w \oplus src1.w
1251 .. opcode:: IMAX - Maximum of Signed Integers
1253 .. math::
1255 dst.x = max(src0.x, src1.x)
1257 dst.y = max(src0.y, src1.y)
1259 dst.z = max(src0.z, src1.z)
1261 dst.w = max(src0.w, src1.w)
1264 .. opcode:: UMAX - Maximum of Unsigned Integers
1266 .. math::
1268 dst.x = max(src0.x, src1.x)
1270 dst.y = max(src0.y, src1.y)
1272 dst.z = max(src0.z, src1.z)
1274 dst.w = max(src0.w, src1.w)
1277 .. opcode:: IMIN - Minimum of Signed Integers
1279 .. math::
1281 dst.x = min(src0.x, src1.x)
1283 dst.y = min(src0.y, src1.y)
1285 dst.z = min(src0.z, src1.z)
1287 dst.w = min(src0.w, src1.w)
1290 .. opcode:: UMIN - Minimum of Unsigned Integers
1292 .. math::
1294 dst.x = min(src0.x, src1.x)
1296 dst.y = min(src0.y, src1.y)
1298 dst.z = min(src0.z, src1.z)
1300 dst.w = min(src0.w, src1.w)
1303 .. opcode:: SHL - Shift Left
1305 The shift count is masked with 0x1f before the shift is applied.
1307 .. math::
1309 dst.x = src0.x << (0x1f \& src1.x)
1311 dst.y = src0.y << (0x1f \& src1.y)
1313 dst.z = src0.z << (0x1f \& src1.z)
1315 dst.w = src0.w << (0x1f \& src1.w)
1318 .. opcode:: ISHR - Arithmetic Shift Right (of Signed Integer)
1320 The shift count is masked with 0x1f before the shift is applied.
1322 .. math::
1324 dst.x = src0.x >> (0x1f \& src1.x)
1326 dst.y = src0.y >> (0x1f \& src1.y)
1328 dst.z = src0.z >> (0x1f \& src1.z)
1330 dst.w = src0.w >> (0x1f \& src1.w)
1333 .. opcode:: USHR - Logical Shift Right
1335 The shift count is masked with 0x1f before the shift is applied.
1337 .. math::
1339 dst.x = src0.x >> (unsigned) (0x1f \& src1.x)
1341 dst.y = src0.y >> (unsigned) (0x1f \& src1.y)
1343 dst.z = src0.z >> (unsigned) (0x1f \& src1.z)
1345 dst.w = src0.w >> (unsigned) (0x1f \& src1.w)
1348 .. opcode:: UCMP - Integer Conditional Move
1350 .. math::
1352 dst.x = src0.x ? src1.x : src2.x
1354 dst.y = src0.y ? src1.y : src2.y
1356 dst.z = src0.z ? src1.z : src2.z
1358 dst.w = src0.w ? src1.w : src2.w
1362 .. opcode:: ISSG - Integer Set Sign
1364 .. math::
1366 dst.x = (src0.x < 0) ? -1 : (src0.x > 0) ? 1 : 0
1368 dst.y = (src0.y < 0) ? -1 : (src0.y > 0) ? 1 : 0
1370 dst.z = (src0.z < 0) ? -1 : (src0.z > 0) ? 1 : 0
1372 dst.w = (src0.w < 0) ? -1 : (src0.w > 0) ? 1 : 0
1376 .. opcode:: FSLT - Float Set On Less Than (ordered)
1378 Same comparison as SLT but returns integer instead of 1.0/0.0 float
1380 .. math::
1382 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1384 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1386 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1388 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1391 .. opcode:: ISLT - Signed Integer Set On Less Than
1393 .. math::
1395 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1397 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1399 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1401 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1404 .. opcode:: USLT - Unsigned Integer Set On Less Than
1406 .. math::
1408 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1410 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1412 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1414 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1417 .. opcode:: FSGE - Float Set On Greater Equal Than (ordered)
1419 Same comparison as SGE but returns integer instead of 1.0/0.0 float
1421 .. math::
1423 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1425 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1427 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1429 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1432 .. opcode:: ISGE - Signed Integer Set On Greater Equal Than
1434 .. math::
1436 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1438 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1440 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1442 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1445 .. opcode:: USGE - Unsigned Integer Set On Greater Equal Than
1447 .. math::
1449 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1451 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1453 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1455 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1458 .. opcode:: FSEQ - Float Set On Equal (ordered)
1460 Same comparison as SEQ but returns integer instead of 1.0/0.0 float
1462 .. math::
1464 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1466 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1468 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1470 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1473 .. opcode:: USEQ - Integer Set On Equal
1475 .. math::
1477 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1479 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1481 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1483 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1486 .. opcode:: FSNE - Float Set On Not Equal (unordered)
1488 Same comparison as SNE but returns integer instead of 1.0/0.0 float
1490 .. math::
1492 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1494 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1496 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1498 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1501 .. opcode:: USNE - Integer Set On Not Equal
1503 .. math::
1505 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1507 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1509 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1511 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1514 .. opcode:: INEG - Integer Negate
1516 Two's complement.
1518 .. math::
1520 dst.x = -src.x
1522 dst.y = -src.y
1524 dst.z = -src.z
1526 dst.w = -src.w
1529 .. opcode:: IABS - Integer Absolute Value
1531 .. math::
1533 dst.x = |src.x|
1535 dst.y = |src.y|
1537 dst.z = |src.z|
1539 dst.w = |src.w|
1541 Bitwise ISA
1542 ^^^^^^^^^^^
1543 These opcodes are used for bit-level manipulation of integers.
1545 .. opcode:: IBFE - Signed Bitfield Extract
1547 Like GLSL bitfieldExtract. Extracts a set of bits from the input, and
1548 sign-extends them if the high bit of the extracted window is set.
1550 Pseudocode::
1552 def ibfe(value, offset, bits):
1553 if offset < 0 or bits < 0 or offset + bits > 32:
1554 return undefined
1555 if bits == 0: return 0
1556 # Note: >> sign-extends
1557 return (value << (32 - offset - bits)) >> (32 - bits)
1559 .. opcode:: UBFE - Unsigned Bitfield Extract
1561 Like GLSL bitfieldExtract. Extracts a set of bits from the input, without
1562 any sign-extension.
1564 Pseudocode::
1566 def ubfe(value, offset, bits):
1567 if offset < 0 or bits < 0 or offset + bits > 32:
1568 return undefined
1569 if bits == 0: return 0
1570 # Note: >> does not sign-extend
1571 return (value << (32 - offset - bits)) >> (32 - bits)
1573 .. opcode:: BFI - Bitfield Insert
1575 Like GLSL bitfieldInsert. Replaces a bit region of 'base' with the low bits
1576 of 'insert'.
1578 Pseudocode::
1580 def bfi(base, insert, offset, bits):
1581 if offset < 0 or bits < 0 or offset + bits > 32:
1582 return undefined
1583 # << defined such that mask == ~0 when bits == 32, offset == 0
1584 mask = ((1 << bits) - 1) << offset
1587 .. opcode:: BREV - Bitfield Reverse
1589 See SM5 instruction BFREV. Reverses the bits of the argument.
1591 .. opcode:: POPC - Population Count
1593 See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
1595 .. opcode:: LSB - Index of lowest set bit
1597 See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
1598 bit of the argument. Returns -1 if none are set.
1600 .. opcode:: IMSB - Index of highest non-sign bit
1602 See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
1603 non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
1604 highest 1 bit for positive numbers). Returns -1 if all bits are the same
1605 (i.e. for inputs 0 and -1).
1607 .. opcode:: UMSB - Index of highest set bit
1609 See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
1610 set bit of the argument. Returns -1 if none are set.
1612 Geometry ISA
1613 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1615 These opcodes are only supported in geometry shaders; they have no meaning
1616 in any other type of shader.
1618 .. opcode:: EMIT - Emit
1620 Generate a new vertex for the current primitive into the specified vertex
1621 stream using the values in the output registers.
1624 .. opcode:: ENDPRIM - End Primitive
1626 Complete the current primitive in the specified vertex stream (consisting of
1627 the emitted vertices), and start a new one.
1630 GLSL ISA
1631 ^^^^^^^^^^
1633 These opcodes are part of :term:GLSL's opcode set. Support for these
1634 opcodes is determined by a special capability bit, GLSL.
1635 Some require glsl version 1.30 (UIF/BREAKC/SWITCH/CASE/DEFAULT/ENDSWITCH).
1637 .. opcode:: CAL - Subroutine Call
1639 push(pc)
1640 pc = target
1643 .. opcode:: RET - Subroutine Call Return
1645 pc = pop()
1648 .. opcode:: CONT - Continue
1650 Unconditionally moves the point of execution to the instruction after the
1651 last bgnloop. The instruction must appear within a bgnloop/endloop.
1653 .. note::
1655 Support for CONT is determined by a special capability bit,
1656 TGSI_CONT_SUPPORTED. See :ref:Screen for more information.
1659 .. opcode:: BGNLOOP - Begin a Loop
1661 Start a loop. Must have a matching endloop.
1664 .. opcode:: BGNSUB - Begin Subroutine
1666 Starts definition of a subroutine. Must have a matching endsub.
1669 .. opcode:: ENDLOOP - End a Loop
1671 End a loop started with bgnloop.
1674 .. opcode:: ENDSUB - End Subroutine
1676 Ends definition of a subroutine.
1679 .. opcode:: NOP - No Operation
1681 Do nothing.
1684 .. opcode:: BRK - Break
1686 Unconditionally moves the point of execution to the instruction after the
1687 next endloop or endswitch. The instruction must appear within a loop/endloop
1688 or switch/endswitch.
1691 .. opcode:: BREAKC - Break Conditional
1693 Conditionally moves the point of execution to the instruction after the
1694 next endloop or endswitch. The instruction must appear within a loop/endloop
1695 or switch/endswitch.
1696 Condition evaluates to true if src0.x != 0 where src0.x is interpreted
1697 as an integer register.
1699 .. note::
1701 Considered for removal as it's quite inconsistent wrt other opcodes
1702 (could emulate with UIF/BRK/ENDIF).
1705 .. opcode:: IF - Float If
1707 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
1709 src0.x != 0.0
1711 where src0.x is interpreted as a floating point register.
1714 .. opcode:: UIF - Bitwise If
1716 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
1718 src0.x != 0
1720 where src0.x is interpreted as an integer register.
1723 .. opcode:: ELSE - Else
1725 Starts an else block, after an IF or UIF statement.
1728 .. opcode:: ENDIF - End If
1730 Ends an IF or UIF block.
1733 .. opcode:: SWITCH - Switch
1735 Starts a C-style switch expression. The switch consists of one or multiple
1736 CASE statements, and at most one DEFAULT statement. Execution of a statement
1737 ends when a BRK is hit, but just like in C falling through to other cases
1738 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
1739 just as last statement, and fallthrough is allowed into/from it.
1740 CASE src arguments are evaluated at bit level against the SWITCH src argument.
1742 Example::
1744 SWITCH src[0].x
1745 CASE src[0].x
1746 (some instructions here)
1747 (optional BRK here)
1748 DEFAULT
1749 (some instructions here)
1750 (optional BRK here)
1751 CASE src[0].x
1752 (some instructions here)
1753 (optional BRK here)
1754 ENDSWITCH
1757 .. opcode:: CASE - Switch case
1759 This represents a switch case label. The src arg must be an integer immediate.
1762 .. opcode:: DEFAULT - Switch default
1764 This represents the default case in the switch, which is taken if no other
1765 case matches.
1768 .. opcode:: ENDSWITCH - End of switch
1770 Ends a switch expression.
1773 Interpolation ISA
1774 ^^^^^^^^^^^^^^^^^
1776 The interpolation instructions allow an input to be interpolated in a
1777 different way than its declaration. This corresponds to the GLSL 4.00
1778 interpolateAt* functions. The first argument of each of these must come from
1779 TGSI_FILE_INPUT.
1781 .. opcode:: INTERP_CENTROID - Interpolate at the centroid
1783 Interpolates the varying specified by src0 at the centroid
1785 .. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
1787 Interpolates the varying specified by src0 at the sample id specified by
1788 src1.x (interpreted as an integer)
1790 .. opcode:: INTERP_OFFSET - Interpolate at the specified offset
1792 Interpolates the varying specified by src0 at the offset src1.xy from the
1793 pixel center (interpreted as floats)
1796 .. _doubleopcodes:
1798 Double ISA
1799 ^^^^^^^^^^^^^^^
1801 The double-precision opcodes reinterpret four-component vectors into
1802 two-component vectors with doubled precision in each component.
1804 .. opcode:: DABS - Absolute
1806 dst.xy = |src0.xy|
1807 dst.zw = |src0.zw|
1811 .. math::
1813 dst.xy = src0.xy + src1.xy
1815 dst.zw = src0.zw + src1.zw
1817 .. opcode:: DSEQ - Set on Equal
1819 .. math::
1821 dst.x = src0.xy == src1.xy ? \sim 0 : 0
1823 dst.z = src0.zw == src1.zw ? \sim 0 : 0
1825 .. opcode:: DSNE - Set on Equal
1827 .. math::
1829 dst.x = src0.xy != src1.xy ? \sim 0 : 0
1831 dst.z = src0.zw != src1.zw ? \sim 0 : 0
1833 .. opcode:: DSLT - Set on Less than
1835 .. math::
1837 dst.x = src0.xy < src1.xy ? \sim 0 : 0
1839 dst.z = src0.zw < src1.zw ? \sim 0 : 0
1841 .. opcode:: DSGE - Set on Greater equal
1843 .. math::
1845 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
1847 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
1849 .. opcode:: DFRAC - Fraction
1851 .. math::
1853 dst.xy = src.xy - \lfloor src.xy\rfloor
1855 dst.zw = src.zw - \lfloor src.zw\rfloor
1857 .. opcode:: DTRUNC - Truncate
1859 .. math::
1861 dst.xy = trunc(src.xy)
1863 dst.zw = trunc(src.zw)
1865 .. opcode:: DCEIL - Ceiling
1867 .. math::
1869 dst.xy = \lceil src.xy\rceil
1871 dst.zw = \lceil src.zw\rceil
1873 .. opcode:: DFLR - Floor
1875 .. math::
1877 dst.xy = \lfloor src.xy\rfloor
1879 dst.zw = \lfloor src.zw\rfloor
1881 .. opcode:: DROUND - Fraction
1883 .. math::
1885 dst.xy = round(src.xy)
1887 dst.zw = round(src.zw)
1889 .. opcode:: DSSG - Set Sign
1891 .. math::
1893 dst.xy = (src.xy > 0) ? 1.0 : (src.xy < 0) ? -1.0 : 0.0
1895 dst.zw = (src.zw > 0) ? 1.0 : (src.zw < 0) ? -1.0 : 0.0
1897 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1899 Like the frexp() routine in many math libraries, this opcode stores the
1900 exponent of its source to dst0, and the significand to dst1, such that
1901 :math:dst1 \times 2^{dst0} = src .
1903 .. math::
1905 dst0.xy = exp(src.xy)
1907 dst1.xy = frac(src.xy)
1909 dst0.zw = exp(src.zw)
1911 dst1.zw = frac(src.zw)
1913 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1915 This opcode is the inverse of :opcode:DFRACEXP. The second
1916 source is an integer.
1918 .. math::
1920 dst.xy = src0.xy \times 2^{src1.x}
1922 dst.zw = src0.zw \times 2^{src1.y}
1924 .. opcode:: DMIN - Minimum
1926 .. math::
1928 dst.xy = min(src0.xy, src1.xy)
1930 dst.zw = min(src0.zw, src1.zw)
1932 .. opcode:: DMAX - Maximum
1934 .. math::
1936 dst.xy = max(src0.xy, src1.xy)
1938 dst.zw = max(src0.zw, src1.zw)
1940 .. opcode:: DMUL - Multiply
1942 .. math::
1944 dst.xy = src0.xy \times src1.xy
1946 dst.zw = src0.zw \times src1.zw
1951 .. math::
1953 dst.xy = src0.xy \times src1.xy + src2.xy
1955 dst.zw = src0.zw \times src1.zw + src2.zw
1958 .. opcode:: DFMA - Fused Multiply-Add
1960 Perform a * b + c with no intermediate rounding step.
1962 .. math::
1964 dst.xy = src0.xy \times src1.xy + src2.xy
1966 dst.zw = src0.zw \times src1.zw + src2.zw
1969 .. opcode:: DDIV - Divide
1971 .. math::
1973 dst.xy = \frac{src0.xy}{src1.xy}
1975 dst.zw = \frac{src0.zw}{src1.zw}
1978 .. opcode:: DRCP - Reciprocal
1980 .. math::
1982 dst.xy = \frac{1}{src.xy}
1984 dst.zw = \frac{1}{src.zw}
1986 .. opcode:: DSQRT - Square Root
1988 .. math::
1990 dst.xy = \sqrt{src.xy}
1992 dst.zw = \sqrt{src.zw}
1994 .. opcode:: DRSQ - Reciprocal Square Root
1996 .. math::
1998 dst.xy = \frac{1}{\sqrt{src.xy}}
2000 dst.zw = \frac{1}{\sqrt{src.zw}}
2002 .. opcode:: F2D - Float to Double
2004 .. math::
2006 dst.xy = double(src0.x)
2008 dst.zw = double(src0.y)
2010 .. opcode:: D2F - Double to Float
2012 .. math::
2014 dst.x = float(src0.xy)
2016 dst.y = float(src0.zw)
2018 .. opcode:: I2D - Int to Double
2020 .. math::
2022 dst.xy = double(src0.x)
2024 dst.zw = double(src0.y)
2026 .. opcode:: D2I - Double to Int
2028 .. math::
2030 dst.x = int(src0.xy)
2032 dst.y = int(src0.zw)
2034 .. opcode:: U2D - Unsigned Int to Double
2036 .. math::
2038 dst.xy = double(src0.x)
2040 dst.zw = double(src0.y)
2042 .. opcode:: D2U - Double to Unsigned Int
2044 .. math::
2046 dst.x = unsigned(src0.xy)
2048 dst.y = unsigned(src0.zw)
2050 64-bit Integer ISA
2051 ^^^^^^^^^^^^^^^^^^
2053 The 64-bit integer opcodes reinterpret four-component vectors into
2054 two-component vectors with 64-bits in each component.
2056 .. opcode:: I64ABS - 64-bit Integer Absolute Value
2058 dst.xy = |src0.xy|
2059 dst.zw = |src0.zw|
2061 .. opcode:: I64NEG - 64-bit Integer Negate
2063 Two's complement.
2065 .. math::
2067 dst.xy = -src.xy
2068 dst.zw = -src.zw
2070 .. opcode:: I64SSG - 64-bit Integer Set Sign
2072 .. math::
2074 dst.xy = (src0.xy < 0) ? -1 : (src0.xy > 0) ? 1 : 0
2075 dst.zw = (src0.zw < 0) ? -1 : (src0.zw > 0) ? 1 : 0
2079 .. math::
2081 dst.xy = src0.xy + src1.xy
2082 dst.zw = src0.zw + src1.zw
2084 .. opcode:: U64MUL - 64-bit Integer Multiply
2086 .. math::
2088 dst.xy = src0.xy * src1.xy
2089 dst.zw = src0.zw * src1.zw
2091 .. opcode:: U64SEQ - 64-bit Integer Set on Equal
2093 .. math::
2095 dst.x = src0.xy == src1.xy ? \sim 0 : 0
2096 dst.z = src0.zw == src1.zw ? \sim 0 : 0
2098 .. opcode:: U64SNE - 64-bit Integer Set on Not Equal
2100 .. math::
2102 dst.x = src0.xy != src1.xy ? \sim 0 : 0
2103 dst.z = src0.zw != src1.zw ? \sim 0 : 0
2105 .. opcode:: U64SLT - 64-bit Unsigned Integer Set on Less Than
2107 .. math::
2109 dst.x = src0.xy < src1.xy ? \sim 0 : 0
2110 dst.z = src0.zw < src1.zw ? \sim 0 : 0
2112 .. opcode:: U64SGE - 64-bit Unsigned Integer Set on Greater Equal
2114 .. math::
2116 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
2117 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
2119 .. opcode:: I64SLT - 64-bit Signed Integer Set on Less Than
2121 .. math::
2123 dst.x = src0.xy < src1.xy ? \sim 0 : 0
2124 dst.z = src0.zw < src1.zw ? \sim 0 : 0
2126 .. opcode:: I64SGE - 64-bit Signed Integer Set on Greater Equal
2128 .. math::
2130 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
2131 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
2133 .. opcode:: I64MIN - Minimum of 64-bit Signed Integers
2135 .. math::
2137 dst.xy = min(src0.xy, src1.xy)
2138 dst.zw = min(src0.zw, src1.zw)
2140 .. opcode:: U64MIN - Minimum of 64-bit Unsigned Integers
2142 .. math::
2144 dst.xy = min(src0.xy, src1.xy)
2145 dst.zw = min(src0.zw, src1.zw)
2147 .. opcode:: I64MAX - Maximum of 64-bit Signed Integers
2149 .. math::
2151 dst.xy = max(src0.xy, src1.xy)
2152 dst.zw = max(src0.zw, src1.zw)
2154 .. opcode:: U64MAX - Maximum of 64-bit Unsigned Integers
2156 .. math::
2158 dst.xy = max(src0.xy, src1.xy)
2159 dst.zw = max(src0.zw, src1.zw)
2161 .. opcode:: U64SHL - Shift Left 64-bit Unsigned Integer
2163 The shift count is masked with 0x3f before the shift is applied.
2165 .. math::
2167 dst.xy = src0.xy << (0x3f \& src1.x)
2168 dst.zw = src0.zw << (0x3f \& src1.y)
2170 .. opcode:: I64SHR - Arithmetic Shift Right (of 64-bit Signed Integer)
2172 The shift count is masked with 0x3f before the shift is applied.
2174 .. math::
2176 dst.xy = src0.xy >> (0x3f \& src1.x)
2177 dst.zw = src0.zw >> (0x3f \& src1.y)
2179 .. opcode:: U64SHR - Logical Shift Right (of 64-bit Unsigned Integer)
2181 The shift count is masked with 0x3f before the shift is applied.
2183 .. math::
2185 dst.xy = src0.xy >> (unsigned) (0x3f \& src1.x)
2186 dst.zw = src0.zw >> (unsigned) (0x3f \& src1.y)
2188 .. opcode:: I64DIV - 64-bit Signed Integer Division
2190 .. math::
2192 dst.xy = src0.xy \ src1.xy
2193 dst.zw = src0.zw \ src1.zw
2195 .. opcode:: U64DIV - 64-bit Unsigned Integer Division
2197 .. math::
2199 dst.xy = src0.xy \ src1.xy
2200 dst.zw = src0.zw \ src1.zw
2202 .. opcode:: U64MOD - 64-bit Unsigned Integer Remainder
2204 .. math::
2206 dst.xy = src0.xy \bmod src1.xy
2207 dst.zw = src0.zw \bmod src1.zw
2209 .. opcode:: I64MOD - 64-bit Signed Integer Remainder
2211 .. math::
2213 dst.xy = src0.xy \bmod src1.xy
2214 dst.zw = src0.zw \bmod src1.zw
2216 .. opcode:: F2U64 - Float to 64-bit Unsigned Int
2218 .. math::
2220 dst.xy = (uint64_t) src0.x
2221 dst.zw = (uint64_t) src0.y
2223 .. opcode:: F2I64 - Float to 64-bit Int
2225 .. math::
2227 dst.xy = (int64_t) src0.x
2228 dst.zw = (int64_t) src0.y
2230 .. opcode:: U2I64 - Unsigned Integer to 64-bit Integer
2232 This is a zero extension.
2234 .. math::
2236 dst.xy = (uint64_t) src0.x
2237 dst.zw = (uint64_t) src0.y
2239 .. opcode:: I2I64 - Signed Integer to 64-bit Integer
2241 This is a sign extension.
2243 .. math::
2245 dst.xy = (int64_t) src0.x
2246 dst.zw = (int64_t) src0.y
2248 .. opcode:: D2U64 - Double to 64-bit Unsigned Int
2250 .. math::
2252 dst.xy = (uint64_t) src0.xy
2253 dst.zw = (uint64_t) src0.zw
2255 .. opcode:: D2I64 - Double to 64-bit Int
2257 .. math::
2259 dst.xy = (int64_t) src0.xy
2260 dst.zw = (int64_t) src0.zw
2262 .. opcode:: U642F - 64-bit unsigned integer to float
2264 .. math::
2266 dst.x = (float) src0.xy
2267 dst.y = (float) src0.zw
2269 .. opcode:: I642F - 64-bit Int to Float
2271 .. math::
2273 dst.x = (float) src0.xy
2274 dst.y = (float) src0.zw
2276 .. opcode:: U642D - 64-bit unsigned integer to double
2278 .. math::
2280 dst.xy = (double) src0.xy
2281 dst.zw = (double) src0.zw
2283 .. opcode:: I642D - 64-bit Int to double
2285 .. math::
2287 dst.xy = (double) src0.xy
2288 dst.zw = (double) src0.zw
2290 .. _samplingopcodes:
2292 Resource Sampling Opcodes
2293 ^^^^^^^^^^^^^^^^^^^^^^^^^
2295 Those opcodes follow very closely semantics of the respective Direct3D
2296 instructions. If in doubt double check Direct3D documentation.
2297 Note that the swizzle on SVIEW (src1) determines texel swizzling
2298 after lookup.
2300 .. opcode:: SAMPLE
2302 Using provided address, sample data from the specified texture using the
2303 filtering mode identified by the given sampler. The source data may come from
2304 any resource type other than buffers.
2306 Syntax: SAMPLE dst, address, sampler_view, sampler
2308 Example: SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]
2310 .. opcode:: SAMPLE_I
2312 Simplified alternative to the SAMPLE instruction. Using the provided
2313 integer address, SAMPLE_I fetches data from the specified sampler view
2314 without any filtering. The source data may come from any resource type
2315 other than CUBE.
2317 Syntax: SAMPLE_I dst, address, sampler_view
2319 Example: SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]
2321 The 'address' is specified as unsigned integers. If the 'address' is out of
2322 range [0...(# texels - 1)] the result of the fetch is always 0 in all
2323 components. As such the instruction doesn't honor address wrap modes, in
2324 cases where that behavior is desirable 'SAMPLE' instruction should be used.
2325 address.w always provides an unsigned integer mipmap level. If the value is
2326 out of the range then the instruction always returns 0 in all components.
2327 address.yz are ignored for buffers and 1d textures. address.z is ignored
2328 for 1d texture arrays and 2d textures.
2330 For 1D texture arrays address.y provides the array index (also as unsigned
2331 integer). If the value is out of the range of available array indices
2332 [0... (array size - 1)] then the opcode always returns 0 in all components.
2333 For 2D texture arrays address.z provides the array index, otherwise it
2334 exhibits the same behavior as in the case for 1D texture arrays. The exact
2335 semantics of the source address are presented in the table below:
2337 +---------------------------+----+-----+-----+---------+
2338 | resource type | X | Y | Z | W |
2339 +===========================+====+=====+=====+=========+
2340 | PIPE_BUFFER | x | | | ignored |
2341 +---------------------------+----+-----+-----+---------+
2342 | PIPE_TEXTURE_1D | x | | | mpl |
2343 +---------------------------+----+-----+-----+---------+
2344 | PIPE_TEXTURE_2D | x | y | | mpl |
2345 +---------------------------+----+-----+-----+---------+
2346 | PIPE_TEXTURE_3D | x | y | z | mpl |
2347 +---------------------------+----+-----+-----+---------+
2348 | PIPE_TEXTURE_RECT | x | y | | mpl |
2349 +---------------------------+----+-----+-----+---------+
2350 | PIPE_TEXTURE_CUBE | not allowed as source |
2351 +---------------------------+----+-----+-----+---------+
2352 | PIPE_TEXTURE_1D_ARRAY | x | idx | | mpl |
2353 +---------------------------+----+-----+-----+---------+
2354 | PIPE_TEXTURE_2D_ARRAY | x | y | idx | mpl |
2355 +---------------------------+----+-----+-----+---------+
2357 Where 'mpl' is a mipmap level and 'idx' is the array index.
2359 .. opcode:: SAMPLE_I_MS
2361 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2363 Syntax: SAMPLE_I_MS dst, address, sampler_view, sample
2365 .. opcode:: SAMPLE_B
2367 Just like the SAMPLE instruction with the exception that an additional bias
2368 is applied to the level of detail computed as part of the instruction
2369 execution.
2371 Syntax: SAMPLE_B dst, address, sampler_view, sampler, lod_bias
2373 Example: SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x
2375 .. opcode:: SAMPLE_C
2377 Similar to the SAMPLE instruction but it performs a comparison filter. The
2378 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2379 additional float32 operand, reference value, which must be a register with
2380 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2381 current samplers compare_func (in pipe_sampler_state) to compare reference
2382 value against the red component value for the surce resource at each texel
2383 that the currently configured texture filter covers based on the provided
2384 coordinates.
2386 Syntax: SAMPLE_C dst, address, sampler_view.r, sampler, ref_value
2388 Example: SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x
2390 .. opcode:: SAMPLE_C_LZ
2392 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2393 for level-zero.
2395 Syntax: SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value
2397 Example: SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x
2400 .. opcode:: SAMPLE_D
2402 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2403 the source address in the x direction and the y direction are provided by
2404 extra parameters.
2406 Syntax: SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y
2408 Example: SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]
2410 .. opcode:: SAMPLE_L
2412 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2413 directly as a scalar value, representing no anisotropy.
2415 Syntax: SAMPLE_L dst, address, sampler_view, sampler, explicit_lod
2417 Example: SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x
2419 .. opcode:: GATHER4
2421 Gathers the four texels to be used in a bi-linear filtering operation and
2422 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2423 and cubemaps arrays. For 2D textures, only the addressing modes of the
2424 sampler and the top level of any mip pyramid are used. Set W to zero. It
2425 behaves like the SAMPLE instruction, but a filtered sample is not
2426 generated. The four samples that contribute to filtering are placed into
2427 xyzw in counter-clockwise order, starting with the (u,v) texture coordinate
2428 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2429 magnitude of the deltas are half a texel.
2432 .. opcode:: SVIEWINFO
2434 Query the dimensions of a given sampler view. dst receives width, height,
2435 depth or array size and number of mipmap levels as int4. The dst can have a
2436 writemask which will specify what info is the caller interested in.
2438 Syntax: SVIEWINFO dst, src_mip_level, sampler_view
2440 Example: SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]
2442 src_mip_level is an unsigned integer scalar. If it's out of range then
2443 returns 0 for width, height and depth/array size but the total number of
2444 mipmap is still returned correctly for the given sampler view. The returned
2445 width, height and depth values are for the mipmap level selected by the
2446 src_mip_level and are in the number of texels. For 1d texture array width
2447 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2448 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2449 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2450 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2451 resinfo allowing swizzling dst values is ignored (due to the interaction
2452 with rcpfloat modifier which requires some swizzle handling in the state
2453 tracker anyway).
2455 .. opcode:: SAMPLE_POS
2457 Query the position of a given sample. dst receives float4 (x, y, 0, 0)
2458 indicated where the sample is located. If the resource is not a multi-sample
2459 resource and not a render target, the result is 0.
2461 .. opcode:: SAMPLE_INFO
2463 dst receives number of samples in x. If the resource is not a multi-sample
2464 resource and not a render target, the result is 0.
2467 .. _resourceopcodes:
2469 Resource Access Opcodes
2470 ^^^^^^^^^^^^^^^^^^^^^^^
2472 .. opcode:: LOAD - Fetch data from a shader buffer or image
2474 Syntax: LOAD dst, resource, address
2476 Example: LOAD TEMP[0], BUFFER[0], TEMP[1]
2479 from the specified buffer or texture without any
2480 filtering.
2482 The 'address' is specified as a vector of unsigned
2483 integers. If the 'address' is out of range the result
2484 is unspecified.
2486 Only the first mipmap level of a resource can be read
2487 from using this instruction.
2489 For 1D or 2D texture arrays, the array index is
2490 provided as an unsigned integer in address.y or
2492 buffers and 1D textures. address.z is ignored for 1D
2493 texture arrays and 2D textures. address.w is always
2494 ignored.
2496 A swizzle suffix may be added to the resource argument
2497 this will cause the resource data to be swizzled accordingly.
2499 .. opcode:: STORE - Write data to a shader resource
2501 Syntax: STORE resource, address, src
2503 Example: STORE BUFFER[0], TEMP[0], TEMP[1]
2505 Using the provided integer address, STORE writes data
2506 to the specified buffer or texture.
2508 The 'address' is specified as a vector of unsigned
2509 integers. If the 'address' is out of range the result
2510 is unspecified.
2512 Only the first mipmap level of a resource can be
2513 written to using this instruction.
2515 For 1D or 2D texture arrays, the array index is
2516 provided as an unsigned integer in address.y or
2518 buffers and 1D textures. address.z is ignored for 1D
2519 texture arrays and 2D textures. address.w is always
2520 ignored.
2522 .. opcode:: RESQ - Query information about a resource
2524 Syntax: RESQ dst, resource
2526 Example: RESQ TEMP[0], BUFFER[0]
2528 Returns information about the buffer or image resource. For buffer
2529 resources, the size (in bytes) is returned in the x component. For
2530 image resources, .xyz will contain the width/height/layers of the
2531 image, while .w will contain the number of samples for multi-sampled
2532 images.
2534 .. opcode:: FBFETCH - Load data from framebuffer
2536 Syntax: FBFETCH dst, output
2538 Example: FBFETCH TEMP[0], OUT[0]
2540 This is only valid on COLOR semantic outputs. Returns the color
2541 of the current position in the framebuffer from before this fragment
2542 shader invocation. May return the same value from multiple calls for
2543 a particular output within a single invocation. Note that result may
2544 be undefined if a fragment is drawn multiple times without a blend
2545 barrier in between.
2551 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2553 These opcodes are intended for communication between threads running
2554 within the same compute grid. For now they're only valid in compute
2555 programs.
2557 .. opcode:: MFENCE - Memory fence
2559 Syntax: MFENCE resource
2561 Example: MFENCE RES[0]
2563 This opcode forces strong ordering between any memory access
2564 operations that affect the specified resource. This means that
2565 previous loads and stores (and only those) will be performed and
2566 visible to other threads before the program execution continues.
2569 .. opcode:: LFENCE - Load memory fence
2571 Syntax: LFENCE resource
2573 Example: LFENCE RES[0]
2575 Similar to MFENCE, but it only affects the ordering of memory loads.
2578 .. opcode:: SFENCE - Store memory fence
2580 Syntax: SFENCE resource
2582 Example: SFENCE RES[0]
2584 Similar to MFENCE, but it only affects the ordering of memory stores.
2587 .. opcode:: BARRIER - Thread group barrier
2589 BARRIER
2591 This opcode suspends the execution of the current thread until all
2592 the remaining threads in the working group reach the same point of
2593 the program. Results are unspecified if any of the remaining
2594 threads terminates or never reaches an executed BARRIER instruction.
2596 .. opcode:: MEMBAR - Memory barrier
2598 MEMBAR type
2600 This opcode waits for the completion of all memory accesses based on
2601 the type passed in. The type is an immediate bitfield with the following
2602 meaning:
2604 Bit 0: Shader storage buffers
2605 Bit 1: Atomic buffers
2606 Bit 2: Images
2607 Bit 3: Shared memory
2610 These may be passed in in any combination. An implementation is free to not
2611 distinguish between these as it sees fit. However these map to all the
2612 possibilities made available by GLSL.
2614 .. _atomopcodes:
2616 Atomic opcodes
2617 ^^^^^^^^^^^^^^
2619 These opcodes provide atomic variants of some common arithmetic and
2620 logical operations. In this context atomicity means that another
2621 concurrent memory access operation that affects the same memory
2622 location is guaranteed to be performed strictly before or after the
2623 entire execution of the atomic operation. The resource may be a buffer
2624 or an image. In the case of an image, the offset works the same as for
2625 LOAD and STORE, specified above. These atomic operations may
2626 only be used with 32-bit integer image formats.
2630 Syntax: ATOMUADD dst, resource, offset, src
2632 Example: ATOMUADD TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2634 The following operation is performed atomically:
2636 .. math::
2638 dst_x = resource[offset]
2640 resource[offset] = dst_x + src_x
2643 .. opcode:: ATOMXCHG - Atomic exchange
2645 Syntax: ATOMXCHG dst, resource, offset, src
2647 Example: ATOMXCHG TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2649 The following operation is performed atomically:
2651 .. math::
2653 dst_x = resource[offset]
2655 resource[offset] = src_x
2658 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2660 Syntax: ATOMCAS dst, resource, offset, cmp, src
2662 Example: ATOMCAS TEMP[0], BUFFER[0], TEMP[1], TEMP[2], TEMP[3]
2664 The following operation is performed atomically:
2666 .. math::
2668 dst_x = resource[offset]
2670 resource[offset] = (dst_x == cmp_x ? src_x : dst_x)
2673 .. opcode:: ATOMAND - Atomic bitwise And
2675 Syntax: ATOMAND dst, resource, offset, src
2677 Example: ATOMAND TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2679 The following operation is performed atomically:
2681 .. math::
2683 dst_x = resource[offset]
2685 resource[offset] = dst_x \& src_x
2688 .. opcode:: ATOMOR - Atomic bitwise Or
2690 Syntax: ATOMOR dst, resource, offset, src
2692 Example: ATOMOR TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2694 The following operation is performed atomically:
2696 .. math::
2698 dst_x = resource[offset]
2700 resource[offset] = dst_x | src_x
2703 .. opcode:: ATOMXOR - Atomic bitwise Xor
2705 Syntax: ATOMXOR dst, resource, offset, src
2707 Example: ATOMXOR TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2709 The following operation is performed atomically:
2711 .. math::
2713 dst_x = resource[offset]
2715 resource[offset] = dst_x \oplus src_x
2718 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2720 Syntax: ATOMUMIN dst, resource, offset, src
2722 Example: ATOMUMIN TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2724 The following operation is performed atomically:
2726 .. math::
2728 dst_x = resource[offset]
2730 resource[offset] = (dst_x < src_x ? dst_x : src_x)
2733 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2735 Syntax: ATOMUMAX dst, resource, offset, src
2737 Example: ATOMUMAX TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2739 The following operation is performed atomically:
2741 .. math::
2743 dst_x = resource[offset]
2745 resource[offset] = (dst_x > src_x ? dst_x : src_x)
2748 .. opcode:: ATOMIMIN - Atomic signed minimum
2750 Syntax: ATOMIMIN dst, resource, offset, src
2752 Example: ATOMIMIN TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2754 The following operation is performed atomically:
2756 .. math::
2758 dst_x = resource[offset]
2760 resource[offset] = (dst_x < src_x ? dst_x : src_x)
2763 .. opcode:: ATOMIMAX - Atomic signed maximum
2765 Syntax: ATOMIMAX dst, resource, offset, src
2767 Example: ATOMIMAX TEMP[0], BUFFER[0], TEMP[1], TEMP[2]
2769 The following operation is performed atomically:
2771 .. math::
2773 dst_x = resource[offset]
2775 resource[offset] = (dst_x > src_x ? dst_x : src_x)
2778 .. _voteopcodes:
2780 Vote opcodes
2781 ^^^^^^^^^^^^
2783 These opcodes compare the given value across the shader invocations
2784 running in the current SIMD group. The details of exactly which
2785 invocations get compared are implementation-defined, and it would be a
2786 correct implementation to only ever consider the current thread's
2787 value. (i.e. SIMD group of 1). The argument is treated as a boolean.
2789 .. opcode:: VOTE_ANY - Value is set in any of the current invocations
2791 .. opcode:: VOTE_ALL - Value is set in all of the current invocations
2793 .. opcode:: VOTE_EQ - Value is the same in all of the current invocations
2796 Explanation of symbols used
2797 ------------------------------
2800 Functions
2801 ^^^^^^^^^^^^^^
2804 :math:|x| Absolute value of x.
2806 :math:\lceil x \rceil Ceiling of x.
2808 clamp(x,y,z) Clamp x between y and z.
2809 (x < y) ? y : (x > z) ? z : x
2811 :math:\lfloor x\rfloor Floor of x.
2813 :math:\log_2{x} Logarithm of x, base 2.
2815 max(x,y) Maximum of x and y.
2816 (x > y) ? x : y
2818 min(x,y) Minimum of x and y.
2819 (x < y) ? x : y
2821 partialx(x) Derivative of x relative to fragment's X.
2823 partialy(x) Derivative of x relative to fragment's Y.
2825 pop() Pop from stack.
2827 :math:x^y x to the power y.
2829 push(x) Push x on stack.
2831 round(x) Round x.
2833 trunc(x) Truncate x, i.e. drop the fraction bits.
2836 Keywords
2837 ^^^^^^^^^^^^^
2842 pc Program counter.
2844 target Label of target instruction.
2847 Other tokens
2848 ---------------
2851 Declaration
2852 ^^^^^^^^^^^
2855 Declares a register that is will be referenced as an operand in Instruction
2856 tokens.
2858 File field contains register file that is being declared and is one
2859 of TGSI_FILE.
2861 UsageMask field specifies which of the register components can be accessed
2862 and is one of TGSI_WRITEMASK.
2864 The Local flag specifies that a given value isn't intended for
2865 subroutine parameter passing and, as a result, the implementation
2866 isn't required to give any guarantees of it being preserved across
2867 subroutine boundaries. As it's merely a compiler hint, the
2868 implementation is free to ignore it.
2870 If Dimension flag is set to 1, a Declaration Dimension token follows.
2872 If Semantic flag is set to 1, a Declaration Semantic token follows.
2874 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
2876 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
2878 If Array flag is set to 1, a Declaration Array token follows.
2880 Array Declaration
2881 ^^^^^^^^^^^^^^^^^^^^^^^^
2883 Declarations can optional have an ArrayID attribute which can be referred by
2884 indirect addressing operands. An ArrayID of zero is reserved and treated as
2885 if no ArrayID is specified.
2887 If an indirect addressing operand refers to a specific declaration by using
2888 an ArrayID only the registers in this declaration are guaranteed to be
2889 accessed, accessing any register outside this declaration results in undefined
2890 behavior. Note that for compatibility the effective index is zero-based and
2891 not relative to the specified declaration
2893 If no ArrayID is specified with an indirect addressing operand the whole
2894 register file might be accessed by this operand. This is strongly discouraged
2895 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
2896 This is only legal for TEMP and CONST register files.
2898 Declaration Semantic
2899 ^^^^^^^^^^^^^^^^^^^^^^^^
2901 Vertex and fragment shader input and output registers may be labeled
2902 with semantic information consisting of a name and index.
2904 Follows Declaration token if Semantic bit is set.
2906 Since its purpose is to link a shader with other stages of the pipeline,
2907 it is valid to follow only those Declaration tokens that declare a register
2908 either in INPUT or OUTPUT file.
2910 SemanticName field contains the semantic name of the register being declared.
2911 There is no default value.
2913 SemanticIndex is an optional subscript that can be used to distinguish
2914 different register declarations with the same semantic name. The default value
2915 is 0.
2917 The meanings of the individual semantic names are explained in the following
2918 sections.
2920 TGSI_SEMANTIC_POSITION
2921 """"""""""""""""""""""
2924 output register which contains the homogeneous vertex position in the clip
2925 space coordinate system. After clipping, the X, Y and Z components of the
2926 vertex will be divided by the W value to get normalized device coordinates.
2928 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
2929 fragment shader input (or system value, depending on which one is
2930 supported by the driver) contains the fragment's window position. The X
2931 component starts at zero and always increases from left to right.
2932 The Y component starts at zero and always increases but Y=0 may either
2933 indicate the top of the window or the bottom depending on the fragment
2934 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
2935 The Z coordinate ranges from 0 to 1 to represent depth from the front
2936 to the back of the Z buffer. The W component contains the interpolated
2937 reciprocal of the vertex position W component (corresponding to gl_Fragcoord,
2938 but unlike d3d10 which interpolates the same 1/w but then gives back
2939 the reciprocal of the interpolated value).
2941 Fragment shaders may also declare an output register with
2942 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
2943 the fragment shader to change the fragment's Z position.
2947 TGSI_SEMANTIC_COLOR
2948 """""""""""""""""""
2951 label indicates that the register contains an R,G,B,A color.
2953 Several shader inputs/outputs may contain colors so the semantic index
2954 is used to distinguish them. For example, color[0] may be the diffuse
2955 color while color[1] may be the specular color.
2957 This label is needed so that the flat/smooth shading can be applied
2958 to the right interpolants during rasterization.
2962 TGSI_SEMANTIC_BCOLOR
2963 """"""""""""""""""""
2965 Back-facing colors are only used for back-facing polygons, and are only valid
2966 in vertex shader outputs. After rasterization, all polygons are front-facing
2967 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
2968 so all BCOLORs effectively become regular COLORs in the fragment shader.
2971 TGSI_SEMANTIC_FOG
2972 """""""""""""""""
2974 Vertex shader inputs and outputs and fragment shader inputs may be
2975 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
2976 a fog coordinate. Typically, the fragment shader will use the fog coordinate
2977 to compute a fog blend factor which is used to blend the normal fragment color
2978 with a constant fog color. But fog coord really is just an ordinary vec4
2979 register like regular semantics.
2982 TGSI_SEMANTIC_PSIZE
2983 """""""""""""""""""
2985 Vertex shader input and output registers may be labeled with
2986 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
2987 in the form (S, 0, 0, 1). The point size controls the width or diameter
2988 of points for rasterization. This label cannot be used in fragment
2991 When using this semantic, be sure to set the appropriate state in the
2992 :ref:rasterizer first.
2995 TGSI_SEMANTIC_TEXCOORD
2996 """"""""""""""""""""""
2998 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
3000 Vertex shader outputs and fragment shader inputs may be labeled with
3001 this semantic to make them replaceable by sprite coordinates via the
3002 sprite_coord_enable state in the :ref:rasterizer.
3003 The semantic index permitted with this semantic is limited to <= 7.
3005 If the driver does not support TEXCOORD, sprite coordinate replacement
3006 applies to inputs with the GENERIC semantic instead.
3008 The intended use case for this semantic is gl_TexCoord.
3011 TGSI_SEMANTIC_PCOORD
3012 """"""""""""""""""""
3014 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
3016 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
3017 that the register contains sprite coordinates in the form (x, y, 0, 1), if
3018 the current primitive is a point and point sprites are enabled. Otherwise,
3019 the contents of the register are undefined.
3021 The intended use case for this semantic is gl_PointCoord.
3024 TGSI_SEMANTIC_GENERIC
3025 """""""""""""""""""""
3027 All vertex/fragment shader inputs/outputs not labeled with any other
3028 semantic label can be considered to be generic attributes. Typical
3029 uses of generic inputs/outputs are texcoords and user-defined values.
3032 TGSI_SEMANTIC_NORMAL
3033 """"""""""""""""""""
3035 Indicates that a vertex shader input is a normal vector. This is
3036 typically only used for legacy graphics APIs.
3039 TGSI_SEMANTIC_FACE
3040 """"""""""""""""""
3042 This label applies to fragment shader inputs (or system values,
3043 depending on which one is supported by the driver) and indicates that
3044 the register contains front/back-face information.
3046 If it is an input, it will be a floating-point vector in the form (F, 0, 0, 1),
3047 where F will be positive when the fragment belongs to a front-facing polygon,
3048 and negative when the fragment belongs to a back-facing polygon.
3050 If it is a system value, it will be an integer vector in the form (F, 0, 0, 1),
3051 where F is 0xffffffff when the fragment belongs to a front-facing polygon and
3052 0 when the fragment belongs to a back-facing polygon.
3055 TGSI_SEMANTIC_EDGEFLAG
3056 """"""""""""""""""""""
3058 For vertex shaders, this sematic label indicates that an input or
3059 output is a boolean edge flag. The register layout is [F, x, x, x]
3060 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
3061 simply copies the edge flag input to the edgeflag output.
3063 Edge flags are used to control which lines or points are actually
3064 drawn when the polygon mode converts triangles/quads/polygons into
3065 points or lines.
3068 TGSI_SEMANTIC_STENCIL
3069 """""""""""""""""""""
3071 For fragment shaders, this semantic label indicates that an output
3072 is a writable stencil reference value. Only the Y component is writable.
3073 This allows the fragment shader to change the fragments stencilref value.
3076 TGSI_SEMANTIC_VIEWPORT_INDEX
3077 """"""""""""""""""""""""""""
3079 For geometry shaders, this semantic label indicates that an output
3080 contains the index of the viewport (and scissor) to use.
3081 This is an integer value, and only the X component is used.
3084 TGSI_SEMANTIC_LAYER
3085 """""""""""""""""""
3087 For geometry shaders, this semantic label indicates that an output
3088 contains the layer value to use for the color and depth/stencil surfaces.
3089 This is an integer value, and only the X component is used.
3090 (Also known as rendertarget array index.)
3093 TGSI_SEMANTIC_CULLDIST
3094 """"""""""""""""""""""
3096 Used as distance to plane for performing application-defined culling
3097 of individual primitives against a plane. When components of vertex
3098 elements are given this label, these values are assumed to be a
3099 float32 signed distance to a plane. Primitives will be completely
3100 discarded if the plane distance for all of the vertices in the
3101 primitive are < 0. If a vertex has a cull distance of NaN, that
3102 vertex counts as "out" (as if its < 0);
3103 The limits on both clip and cull distances are bound
3104 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
3105 the maximum number of components that can be used to hold the
3106 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
3107 which specifies the maximum number of registers which can be
3108 annotated with those semantics.
3111 TGSI_SEMANTIC_CLIPDIST
3112 """"""""""""""""""""""
3114 Note this covers clipping and culling distances.
3116 When components of vertex elements are identified this way, these
3117 values are each assumed to be a float32 signed distance to a plane.
3119 For clip distances:
3120 Primitive setup only invokes rasterization on pixels for which
3121 the interpolated plane distances are >= 0.
3123 For cull distances:
3124 Primitives will be completely discarded if the plane distance
3125 for all of the vertices in the primitive are < 0.
3126 If a vertex has a cull distance of NaN, that vertex counts as "out"
3127 (as if its < 0);
3129 Multiple clip/cull planes can be implemented simultaneously, by
3130 annotating multiple components of one or more vertex elements with
3131 the above specified semantic.
3132 The limits on both clip and cull distances are bound
3133 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
3134 the maximum number of components that can be used to hold the
3135 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
3136 which specifies the maximum number of registers which can be
3137 annotated with those semantics.
3138 The properties NUM_CLIPDIST_ENABLED and NUM_CULLDIST_ENABLED
3139 are used to divide up the 2 x vec4 space between clipping and culling.
3141 TGSI_SEMANTIC_SAMPLEID
3142 """"""""""""""""""""""
3144 For fragment shaders, this semantic label indicates that a system value
3145 contains the current sample id (i.e. gl_SampleID).
3146 This is an integer value, and only the X component is used.
3148 TGSI_SEMANTIC_SAMPLEPOS
3149 """""""""""""""""""""""
3151 For fragment shaders, this semantic label indicates that a system value
3152 contains the current sample's position (i.e. gl_SamplePosition). Only the X
3153 and Y values are used.
3156 """"""""""""""""""""""""
3158 For fragment shaders, this semantic label indicates that an output contains
3159 the sample mask used to disable further sample processing
3160 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
3162 TGSI_SEMANTIC_INVOCATIONID
3163 """"""""""""""""""""""""""
3165 For geometry shaders, this semantic label indicates that a system value
3166 contains the current invocation id (i.e. gl_InvocationID).
3167 This is an integer value, and only the X component is used.
3169 TGSI_SEMANTIC_INSTANCEID
3170 """"""""""""""""""""""""
3172 For vertex shaders, this semantic label indicates that a system value contains
3173 the current instance id (i.e. gl_InstanceID). It does not include the base
3174 instance. This is an integer value, and only the X component is used.
3176 TGSI_SEMANTIC_VERTEXID
3177 """"""""""""""""""""""
3179 For vertex shaders, this semantic label indicates that a system value contains
3180 the current vertex id (i.e. gl_VertexID). It does (unlike in d3d10) include the
3181 base vertex. This is an integer value, and only the X component is used.
3183 TGSI_SEMANTIC_VERTEXID_NOBASE
3184 """""""""""""""""""""""""""""""
3186 For vertex shaders, this semantic label indicates that a system value contains
3187 the current vertex id without including the base vertex (this corresponds to
3188 d3d10 vertex id, so TGSI_SEMANTIC_VERTEXID_NOBASE + TGSI_SEMANTIC_BASEVERTEX
3189 == TGSI_SEMANTIC_VERTEXID). This is an integer value, and only the X component
3190 is used.
3192 TGSI_SEMANTIC_BASEVERTEX
3193 """"""""""""""""""""""""
3195 For vertex shaders, this semantic label indicates that a system value contains
3196 the base vertex (i.e. gl_BaseVertex). Note that for non-indexed draw calls,
3197 this contains the first (or start) value instead.
3198 This is an integer value, and only the X component is used.
3200 TGSI_SEMANTIC_PRIMID
3201 """"""""""""""""""""
3203 For geometry and fragment shaders, this semantic label indicates the value
3204 contains the primitive id (i.e. gl_PrimitiveID). This is an integer value,
3205 and only the X component is used.
3206 FIXME: This right now can be either a ordinary input or a system value...
3209 TGSI_SEMANTIC_PATCH
3210 """""""""""""""""""
3212 For tessellation evaluation/control shaders, this semantic label indicates a
3213 generic per-patch attribute. Such semantics will not implicitly be per-vertex
3214 arrays.
3216 TGSI_SEMANTIC_TESSCOORD
3217 """""""""""""""""""""""
3219 For tessellation evaluation shaders, this semantic label indicates the
3220 coordinates of the vertex being processed. This is available in XYZ; W is
3221 undefined.
3223 TGSI_SEMANTIC_TESSOUTER
3224 """""""""""""""""""""""
3226 For tessellation evaluation/control shaders, this semantic label indicates the
3227 outer tessellation levels of the patch. Isoline tessellation will only have XY
3228 defined, triangle will have XYZ and quads will have XYZW defined. This
3229 corresponds to gl_TessLevelOuter.
3231 TGSI_SEMANTIC_TESSINNER
3232 """""""""""""""""""""""
3234 For tessellation evaluation/control shaders, this semantic label indicates the
3235 inner tessellation levels of the patch. The X value is only defined for
3236 triangle tessellation, while quads will have XY defined. This is entirely
3237 undefined for isoline tessellation.
3239 TGSI_SEMANTIC_VERTICESIN
3240 """"""""""""""""""""""""
3242 For tessellation evaluation/control shaders, this semantic label indicates the
3243 number of vertices provided in the input patch. Only the X value is defined.
3245 TGSI_SEMANTIC_HELPER_INVOCATION
3246 """""""""""""""""""""""""""""""
3248 For fragment shaders, this semantic indicates whether the current
3249 invocation is covered or not. Helper invocations are created in order
3250 to properly compute derivatives, however it may be desirable to skip
3251 some of the logic in those cases. See gl_HelperInvocation documentation.
3253 TGSI_SEMANTIC_BASEINSTANCE
3254 """"""""""""""""""""""""""
3256 For vertex shaders, the base instance argument supplied for this
3257 draw. This is an integer value, and only the X component is used.
3259 TGSI_SEMANTIC_DRAWID
3260 """"""""""""""""""""
3262 For vertex shaders, the zero-based index of the current draw in a
3263 glMultiDraw* invocation. This is an integer value, and only the X
3264 component is used.
3267 TGSI_SEMANTIC_WORK_DIM
3268 """"""""""""""""""""""
3270 For compute shaders started via opencl this retrieves the work_dim
3271 parameter to the clEnqueueNDRangeKernel call with which the shader
3272 was started.
3275 TGSI_SEMANTIC_GRID_SIZE
3276 """""""""""""""""""""""
3278 For compute shaders, this semantic indicates the maximum (x, y, z) dimensions
3279 of a grid of thread blocks.
3282 TGSI_SEMANTIC_BLOCK_ID
3283 """"""""""""""""""""""
3285 For compute shaders, this semantic indicates the (x, y, z) coordinates of the
3286 current block inside of the grid.
3289 TGSI_SEMANTIC_BLOCK_SIZE
3290 """"""""""""""""""""""""
3292 For compute shaders, this semantic indicates the maximum (x, y, z) dimensions
3293 of a block in threads.
3297 """""""""""""""""""""""
3299 For compute shaders, this semantic indicates the (x, y, z) coordinates of the
3300 current thread inside of the block.
3303 Declaration Interpolate
3304 ^^^^^^^^^^^^^^^^^^^^^^^
3306 This token is only valid for fragment shader INPUT declarations.
3308 The Interpolate field specifes the way input is being interpolated by
3309 the rasteriser and is one of TGSI_INTERPOLATE_*.
3311 The Location field specifies the location inside the pixel that the
3312 interpolation should be done at, one of TGSI_INTERPOLATE_LOC_*. Note that
3313 when per-sample shading is enabled, the implementation may choose to
3314 interpolate at the sample irrespective of the Location field.
3316 The CylindricalWrap bitfield specifies which register components
3317 should be subject to cylindrical wrapping when interpolating by the
3318 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
3319 should be interpolated according to cylindrical wrapping rules.
3322 Declaration Sampler View
3323 ^^^^^^^^^^^^^^^^^^^^^^^^
3325 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
3327 DCL SVIEW[#], resource, type(s)
3329 Declares a shader input sampler view and assigns it to a SVIEW[#]
3330 register.
3332 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
3334 type must be 1 or 4 entries (if specifying on a per-component
3335 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
3337 For TEX\* style texture sample opcodes (as opposed to SAMPLE\* opcodes
3338 which take an explicit SVIEW[#] source register), there may be optionally
3339 SVIEW[#] declarations. In this case, the SVIEW index is implied by the
3340 SAMP index, and there must be a corresponding SVIEW[#] declaration for
3341 each SAMP[#] declaration. Drivers are free to ignore this if they wish.
3342 But note in particular that some drivers need to know the sampler type
3343 (float/int/unsigned) in order to generate the correct code, so cases
3344 where integer textures are sampled, SVIEW[#] declarations should be
3345 used.
3347 NOTE: It is NOT legal to mix SAMPLE\* style opcodes and TEX\* opcodes
3350 Declaration Resource
3351 ^^^^^^^^^^^^^^^^^^^^
3353 Follows Declaration token if file is TGSI_FILE_RESOURCE.
3355 DCL RES[#], resource [, WR] [, RAW]
3357 Declares a shader input resource and assigns it to a RES[#]
3358 register.
3360 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
3361 2DArray.
3363 If the RAW keyword is not specified, the texture data will be
3364 subject to conversion, swizzling and scaling as required to yield
3365 the specified data type from the physical data format of the bound
3366 resource.
3368 If the RAW keyword is specified, no channel conversion will be
3369 performed: the values read for each of the channels (X,Y,Z,W) will
3370 correspond to consecutive words in the same order and format
3371 they're found in memory. No element-to-address conversion will be
3372 performed either: the value of the provided X coordinate will be
3373 interpreted in byte units instead of texel units. The result of
3374 accessing a misaligned address is undefined.
3376 Usage of the STORE opcode is only allowed if the WR (writable) flag
3377 is set.
3380 Properties
3381 ^^^^^^^^^^^^^^^^^^^^^^^^
3383 Properties are general directives that apply to the whole TGSI program.
3385 FS_COORD_ORIGIN
3386 """""""""""""""
3388 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
3389 The default value is UPPER_LEFT.
3391 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
3392 increase downward and rightward.
3393 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
3394 increase upward and rightward.
3396 OpenGL defaults to LOWER_LEFT, and is configurable with the
3397 GL_ARB_fragment_coord_conventions extension.
3399 DirectX 9/10 use UPPER_LEFT.
3401 FS_COORD_PIXEL_CENTER
3402 """""""""""""""""""""
3404 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
3405 The default value is HALF_INTEGER.
3407 If HALF_INTEGER, the fractionary part of the position will be 0.5
3408 If INTEGER, the fractionary part of the position will be 0.0
3410 Note that this does not affect the set of fragments generated by
3411 rasterization, which is instead controlled by half_pixel_center in the
3412 rasterizer.
3414 OpenGL defaults to HALF_INTEGER, and is configurable with the
3415 GL_ARB_fragment_coord_conventions extension.
3417 DirectX 9 uses INTEGER.
3418 DirectX 10 uses HALF_INTEGER.
3420 FS_COLOR0_WRITES_ALL_CBUFS
3421 """"""""""""""""""""""""""
3422 Specifies that writes to the fragment shader color 0 are replicated to all
3423 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
3424 fragData is directed to a single color buffer, but fragColor is broadcast.
3426 VS_PROHIBIT_UCPS
3427 """"""""""""""""""""""""""
3428 If this property is set on the program bound to the shader stage before the
3429 fragment shader, user clip planes should have no effect (be disabled) even if
3430 that shader does not write to any clip distance outputs and the rasterizer's
3431 clip_plane_enable is non-zero.
3432 This property is only supported by drivers that also support shader clip
3433 distance outputs.
3434 This is useful for APIs that don't have UCPs and where clip distances written
3435 by a shader cannot be disabled.
3437 GS_INVOCATIONS
3438 """"""""""""""
3440 Specifies the number of times a geometry shader should be executed for each
3441 input primitive. Each invocation will have a different
3442 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
3443 be 1.
3445 VS_WINDOW_SPACE_POSITION
3446 """"""""""""""""""""""""""
3447 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
3448 is assumed to contain window space coordinates.
3449 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
3450 directly taken from the 4-th component of the shader output.
3451 Naturally, clipping is not performed on window coordinates either.
3452 The effect of this property is undefined if a geometry or tessellation shader
3453 are in use.
3455 TCS_VERTICES_OUT
3456 """"""""""""""""
3458 The number of vertices written by the tessellation control shader. This
3459 effectively defines the patch input size of the tessellation evaluation shader
3460 as well.
3462 TES_PRIM_MODE
3463 """""""""""""
3465 This sets the tessellation primitive mode, one of PIPE_PRIM_TRIANGLES,
3466 PIPE_PRIM_QUADS, or PIPE_PRIM_LINES. (Unlike in GL, there is no
3467 separate isolines settings, the regular lines is assumed to mean isolines.)
3469 TES_SPACING
3470 """""""""""
3472 This sets the spacing mode of the tessellation generator, one of
3473 PIPE_TESS_SPACING_*.
3475 TES_VERTEX_ORDER_CW
3476 """""""""""""""""""
3478 This sets the vertex order to be clockwise if the value is 1, or
3479 counter-clockwise if set to 0.
3481 TES_POINT_MODE
3482 """"""""""""""
3484 If set to a non-zero value, this turns on point mode for the tessellator,
3485 which means that points will be generated instead of primitives.
3487 NUM_CLIPDIST_ENABLED
3488 """"""""""""""""
3490 How many clip distance scalar outputs are enabled.
3492 NUM_CULLDIST_ENABLED
3493 """"""""""""""""
3495 How many cull distance scalar outputs are enabled.
3497 FS_EARLY_DEPTH_STENCIL
3498 """"""""""""""""""""""
3500 Whether depth test, stencil test, and occlusion query should run before
3502 to GLSL early_fragment_tests.
3505 """""""""""
3508 is bound. This is only a hint to the driver and doesn't have to be precise.
3509 Only set for VS and TES.
3511 CS_FIXED_BLOCK_WIDTH / HEIGHT / DEPTH
3512 """""""""""""""""""""""""""""""""""""
3514 Threads per block in each dimension, if known at compile time. If the block size
3515 is known all three should be at least 1. If it is unknown they should all be set
3516 to 0 or not set.
3518 MUL_ZERO_WINS
3519 """""""""""""
3521 The MUL TGSI operation (FP32 multiplication) will return 0 if either
3522 of the operands are equal to 0. That means that 0 * Inf = 0. This
3523 should be set the same way for an entire pipeline. Note that this
3524 applies not only to the literal MUL TGSI opcode, but all FP32
3525 multiplications implied by other operations, such as MAD, FMA, DP2,
3526 DP3, DP4, DPH, DST, LOG, LRP, XPD, and possibly others. If there is a
3527 mismatch between shaders, then it is unspecified whether this behavior
3528 will be enabled.
3531 Texture Sampling and Texture Formats
3532 ------------------------------------
3534 This table shows how texture image components are returned as (x,y,z,w) tuples
3535 by TGSI texture instructions, such as :opcode:TEX, :opcode:TXD, and
3536 :opcode:TXP. For reference, OpenGL and Direct3D conventions are shown as
3537 well.
3539 +--------------------+--------------+--------------------+--------------+
3540 | Texture Components | Gallium | OpenGL | Direct3D 9 |
3541 +====================+==============+====================+==============+
3542 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
3543 +--------------------+--------------+--------------------+--------------+
3544 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
3545 +--------------------+--------------+--------------------+--------------+
3546 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
3547 +--------------------+--------------+--------------------+--------------+
3548 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
3549 +--------------------+--------------+--------------------+--------------+
3550 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
3551 +--------------------+--------------+--------------------+--------------+
3552 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
3553 +--------------------+--------------+--------------------+--------------+
3554 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
3555 +--------------------+--------------+--------------------+--------------+
3556 | I | (i, i, i, i) | (i, i, i, i) | N/A |
3557 +--------------------+--------------+--------------------+--------------+
3558 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
3559 | | | [#envmap-bumpmap]_ | |
3560 +--------------------+--------------+--------------------+--------------+
3561 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
3562 | | | [#depth-tex-mode]_ | |
3563 +--------------------+--------------+--------------------+--------------+
3564 | S | (s, s, s, s) | unknown | unknown |
3565 +--------------------+--------------+--------------------+--------------+
3567 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
3568 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
3569 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.