4 TGSI, Tungsten Graphics Shader Infrastructure, is an intermediate language
5 for describing shaders. Since Gallium is inherently shaderful, shaders are
6 an important part of the API. TGSI is the only intermediate representation
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
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.
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
42 ^^^^^^^^^^^^^^^^^^^^^^^^^
44 These opcodes are guaranteed to be available regardless of the driver being
47 .. opcode:: ARL - Address Register Load
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
73 .. opcode:: LIT - Light Coefficients
78 dst.y &= max(src.x, 0) \\
79 dst.z &= (src.x > 0) ? max(src.y, 0)^{clamp(src.w, -128, 128))} : 0 \\
83 .. opcode:: RCP - Reciprocal
85 This instruction replicates its result.
92 .. opcode:: RSQ - Reciprocal Square Root
94 This instruction replicates its result. The results are undefined for src <= 0.
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.
110 .. opcode:: EXP - Approximate Exponential Base 2
114 dst.x &= 2^{\lfloor src.x\rfloor} \\
115 dst.y &= src.x - \lfloor src.x\rfloor \\
116 dst.z &= 2^{src.x} \\
120 .. opcode:: LOG - Approximate Logarithm Base 2
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|} \\
130 .. opcode:: MUL - Multiply
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
143 .. opcode:: ADD - Add
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.
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.
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
179 dst.y &= src0.y \times src1.y\\
184 .. opcode:: MIN - Minimum
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
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
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
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
236 .. opcode:: MAD - Multiply And Add
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
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.
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
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
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
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
329 .. opcode:: EX2 - Exponential Base 2
331 This instruction replicates its result.
338 .. opcode:: LG2 - Logarithm Base 2
340 This instruction replicates its result.
347 .. opcode:: POW - Power
349 This instruction replicates its result.
353 dst = src0.x^{src1.x}
355 .. opcode:: XPD - Cross Product
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
368 .. opcode:: DPH - Homogeneous Dot Product
370 This instruction replicates its result.
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.
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.
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.
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.
426 dst = f32\_to\_f16(src.x) | f32\_to\_f16(src.y) << 16
429 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
434 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
439 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
444 .. opcode:: SEQ - Set On Equal
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
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.
479 .. opcode:: SLE - Set On Less Equal Than
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
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.
524 shadow_ref = src0.z or src0.w (optional)
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
544 dst = texture\_sample(unit, coord, shadow_ref)
549 .. opcode:: TXD - Texture Lookup with Derivatives
561 dst = texture\_sample\_deriv(unit, coord, ddx, ddy)
564 .. opcode:: TXP - Projective Texture Lookup
568 coord.x = src0.x / src0.w
570 coord.y = src0.y / src0.w
572 coord.z = src0.z / src0.w
578 dst = texture\_sample(unit, coord)
581 .. opcode:: UP2H - Unpack Two 16-Bit Floats
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)
595 Considered for removal.
597 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
603 Considered for removal.
605 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
611 Considered for removal.
613 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
619 Considered for removal.
622 .. opcode:: ARR - Address Register Load With Round
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
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
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
663 Conditional discard. Allowed in fragment shaders only.
667 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
672 .. opcode:: KILL - Discard
674 Unconditional discard. Allowed in fragment shaders only.
677 .. opcode:: SCS - Sine Cosine
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).
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.
720 Presumably shadow 2d arrays and shadow 3d targets could use
721 this encoding too, but this is not legal.
723 shadow cube map arrays are neither possible nor required.
733 dst = texture\_sample(unit, coord, bias)
736 .. opcode:: DIV - Divide
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.
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).
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
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.
801 dst = texture\_sample(unit, coord, lod)
804 .. opcode:: PUSHA - Push Address Register On Stack
813 Considered for cleanup.
817 Considered for removal.
819 .. opcode:: POPA - Pop Address Register From Stack
828 Considered for cleanup.
832 Considered for removal.
835 .. opcode:: CALLNZ - Subroutine Call If Not Zero
841 Considered for cleanup.
845 Considered for removal.
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
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
882 .. opcode:: MOD - Modulus
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
895 .. opcode:: UARL - Integer Address Register Load
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
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)
933 For components which don't return a resource dimension, their value
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.
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
983 dst = texture\_gather4 (unit, coord, component)
985 (with SM5 - cube array shadow)
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
1006 dst.xy = lodq(uint, coord);
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).
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).
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.
1060 .. opcode:: F2U - Float to Unsigned Integer
1062 Rounding is towards zero (truncate).
1063 Values outside unsigned range (including NaNs) produce undefined results.
1067 dst.x = (unsigned) src.x
1069 dst.y = (unsigned) src.y
1071 dst.z = (unsigned) src.z
1073 dst.w = (unsigned) src.w
1076 .. opcode:: UADD - Integer Add
1078 This instruction works the same for signed and unsigned integers.
1079 The low 32bit of the result is returned.
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
1092 .. opcode:: UMAD - Integer Multiply And Add
1094 This instruction works the same for signed and unsigned integers.
1095 The multiplication returns the low 32bit (as does the result itself).
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.
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.
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.
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.
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.
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.
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
1212 .. opcode:: AND - Bitwise And
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
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
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
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
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
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
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.
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.
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.
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
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
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
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
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
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
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
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
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
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
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
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
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
1529 .. opcode:: IABS - Integer Absolute Value
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.
1552 def ibfe(value, offset, bits):
1553 if offset < 0 or bits < 0 or offset + bits > 32:
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
1566 def ubfe(value, offset, bits):
1567 if offset < 0 or bits < 0 or offset + bits > 32:
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
1580 def bfi(base, insert, offset, bits):
1581 if offset < 0 or bits < 0 or offset + bits > 32:
1583 # << defined such that mask == ~0 when bits == 32, offset == 0
1584 mask = ((1 << bits) - 1) << offset
1585 return ((insert << offset) & mask) | (base & ~mask)
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.
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.
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
1643 .. opcode:: RET - Subroutine Call Return
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.
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
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.
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
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
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.
1746 (some instructions here)
1749 (some instructions here)
1752 (some instructions here)
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
1768 .. opcode:: ENDSWITCH - End of switch
1770 Ends a switch expression.
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)
1801 The double-precision opcodes reinterpret four-component vectors into
1802 two-component vectors with doubled precision in each component.
1804 .. opcode:: DABS - Absolute
1811 .. opcode:: DADD - Add
1815 dst.xy = src0.xy + src1.xy
1817 dst.zw = src0.zw + src1.zw
1819 .. opcode:: DSEQ - Set on Equal
1823 dst.x = src0.xy == src1.xy ? \sim 0 : 0
1825 dst.z = src0.zw == src1.zw ? \sim 0 : 0
1827 .. opcode:: DSNE - Set on Equal
1831 dst.x = src0.xy != src1.xy ? \sim 0 : 0
1833 dst.z = src0.zw != src1.zw ? \sim 0 : 0
1835 .. opcode:: DSLT - Set on Less than
1839 dst.x = src0.xy < src1.xy ? \sim 0 : 0
1841 dst.z = src0.zw < src1.zw ? \sim 0 : 0
1843 .. opcode:: DSGE - Set on Greater equal
1847 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
1849 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
1851 .. opcode:: DFRAC - Fraction
1855 dst.xy = src.xy - \lfloor src.xy\rfloor
1857 dst.zw = src.zw - \lfloor src.zw\rfloor
1859 .. opcode:: DTRUNC - Truncate
1863 dst.xy = trunc(src.xy)
1865 dst.zw = trunc(src.zw)
1867 .. opcode:: DCEIL - Ceiling
1871 dst.xy = \lceil src.xy\rceil
1873 dst.zw = \lceil src.zw\rceil
1875 .. opcode:: DFLR - Floor
1879 dst.xy = \lfloor src.xy\rfloor
1881 dst.zw = \lfloor src.zw\rfloor
1883 .. opcode:: DROUND - Fraction
1887 dst.xy = round(src.xy)
1889 dst.zw = round(src.zw)
1891 .. opcode:: DSSG - Set Sign
1895 dst.xy = (src.xy > 0) ? 1.0 : (src.xy < 0) ? -1.0 : 0.0
1897 dst.zw = (src.zw > 0) ? 1.0 : (src.zw < 0) ? -1.0 : 0.0
1899 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1901 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1902 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1903 :math:`dst1 \times 2^{dst0} = src` .
1907 dst0.xy = exp(src.xy)
1909 dst1.xy = frac(src.xy)
1911 dst0.zw = exp(src.zw)
1913 dst1.zw = frac(src.zw)
1915 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1917 This opcode is the inverse of :opcode:`DFRACEXP`. The second
1918 source is an integer.
1922 dst.xy = src0.xy \times 2^{src1.x}
1924 dst.zw = src0.zw \times 2^{src1.y}
1926 .. opcode:: DMIN - Minimum
1930 dst.xy = min(src0.xy, src1.xy)
1932 dst.zw = min(src0.zw, src1.zw)
1934 .. opcode:: DMAX - Maximum
1938 dst.xy = max(src0.xy, src1.xy)
1940 dst.zw = max(src0.zw, src1.zw)
1942 .. opcode:: DMUL - Multiply
1946 dst.xy = src0.xy \times src1.xy
1948 dst.zw = src0.zw \times src1.zw
1951 .. opcode:: DMAD - Multiply And Add
1955 dst.xy = src0.xy \times src1.xy + src2.xy
1957 dst.zw = src0.zw \times src1.zw + src2.zw
1960 .. opcode:: DFMA - Fused Multiply-Add
1962 Perform a * b + c with no intermediate rounding step.
1966 dst.xy = src0.xy \times src1.xy + src2.xy
1968 dst.zw = src0.zw \times src1.zw + src2.zw
1971 .. opcode:: DDIV - Divide
1975 dst.xy = \frac{src0.xy}{src1.xy}
1977 dst.zw = \frac{src0.zw}{src1.zw}
1980 .. opcode:: DRCP - Reciprocal
1984 dst.xy = \frac{1}{src.xy}
1986 dst.zw = \frac{1}{src.zw}
1988 .. opcode:: DSQRT - Square Root
1992 dst.xy = \sqrt{src.xy}
1994 dst.zw = \sqrt{src.zw}
1996 .. opcode:: DRSQ - Reciprocal Square Root
2000 dst.xy = \frac{1}{\sqrt{src.xy}}
2002 dst.zw = \frac{1}{\sqrt{src.zw}}
2004 .. opcode:: F2D - Float to Double
2008 dst.xy = double(src0.x)
2010 dst.zw = double(src0.y)
2012 .. opcode:: D2F - Double to Float
2016 dst.x = float(src0.xy)
2018 dst.y = float(src0.zw)
2020 .. opcode:: I2D - Int to Double
2024 dst.xy = double(src0.x)
2026 dst.zw = double(src0.y)
2028 .. opcode:: D2I - Double to Int
2032 dst.x = int(src0.xy)
2034 dst.y = int(src0.zw)
2036 .. opcode:: U2D - Unsigned Int to Double
2040 dst.xy = double(src0.x)
2042 dst.zw = double(src0.y)
2044 .. opcode:: D2U - Double to Unsigned Int
2048 dst.x = unsigned(src0.xy)
2050 dst.y = unsigned(src0.zw)
2055 The 64-bit integer opcodes reinterpret four-component vectors into
2056 two-component vectors with 64-bits in each component.
2058 .. opcode:: I64ABS - 64-bit Integer Absolute Value
2065 .. opcode:: I64NEG - 64-bit Integer Negate
2074 .. opcode:: I64SSG - 64-bit Integer Set Sign
2078 dst.xy = (src0.xy < 0) ? -1 : (src0.xy > 0) ? 1 : 0
2079 dst.zw = (src0.zw < 0) ? -1 : (src0.zw > 0) ? 1 : 0
2081 .. opcode:: U64ADD - 64-bit Integer Add
2085 dst.xy = src0.xy + src1.xy
2086 dst.zw = src0.zw + src1.zw
2088 .. opcode:: U64MUL - 64-bit Integer Multiply
2092 dst.xy = src0.xy * src1.xy
2093 dst.zw = src0.zw * src1.zw
2095 .. opcode:: U64SEQ - 64-bit Integer Set on Equal
2099 dst.x = src0.xy == src1.xy ? \sim 0 : 0
2100 dst.z = src0.zw == src1.zw ? \sim 0 : 0
2102 .. opcode:: U64SNE - 64-bit Integer Set on Not Equal
2106 dst.x = src0.xy != src1.xy ? \sim 0 : 0
2107 dst.z = src0.zw != src1.zw ? \sim 0 : 0
2109 .. opcode:: U64SLT - 64-bit Unsigned Integer Set on Less Than
2113 dst.x = src0.xy < src1.xy ? \sim 0 : 0
2114 dst.z = src0.zw < src1.zw ? \sim 0 : 0
2116 .. opcode:: U64SGE - 64-bit Unsigned Integer Set on Greater Equal
2120 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
2121 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
2123 .. opcode:: I64SLT - 64-bit Signed Integer Set on Less Than
2127 dst.x = src0.xy < src1.xy ? \sim 0 : 0
2128 dst.z = src0.zw < src1.zw ? \sim 0 : 0
2130 .. opcode:: I64SGE - 64-bit Signed Integer Set on Greater Equal
2134 dst.x = src0.xy >= src1.xy ? \sim 0 : 0
2135 dst.z = src0.zw >= src1.zw ? \sim 0 : 0
2137 .. opcode:: I64MIN - Minimum of 64-bit Signed Integers
2141 dst.xy = min(src0.xy, src1.xy)
2142 dst.zw = min(src0.zw, src1.zw)
2144 .. opcode:: U64MIN - Minimum of 64-bit Unsigned Integers
2148 dst.xy = min(src0.xy, src1.xy)
2149 dst.zw = min(src0.zw, src1.zw)
2151 .. opcode:: I64MAX - Maximum of 64-bit Signed Integers
2155 dst.xy = max(src0.xy, src1.xy)
2156 dst.zw = max(src0.zw, src1.zw)
2158 .. opcode:: U64MAX - Maximum of 64-bit Unsigned Integers
2162 dst.xy = max(src0.xy, src1.xy)
2163 dst.zw = max(src0.zw, src1.zw)
2165 .. opcode:: U64SHL - Shift Left 64-bit Unsigned Integer
2167 The shift count is masked with 0x3f before the shift is applied.
2171 dst.xy = src0.xy << (0x3f \& src1.x)
2172 dst.zw = src0.zw << (0x3f \& src1.y)
2174 .. opcode:: I64SHR - Arithmetic Shift Right (of 64-bit Signed Integer)
2176 The shift count is masked with 0x3f before the shift is applied.
2180 dst.xy = src0.xy >> (0x3f \& src1.x)
2181 dst.zw = src0.zw >> (0x3f \& src1.y)
2183 .. opcode:: U64SHR - Logical Shift Right (of 64-bit Unsigned Integer)
2185 The shift count is masked with 0x3f before the shift is applied.
2189 dst.xy = src0.xy >> (unsigned) (0x3f \& src1.x)
2190 dst.zw = src0.zw >> (unsigned) (0x3f \& src1.y)
2192 .. opcode:: I64DIV - 64-bit Signed Integer Division
2196 dst.xy = src0.xy \ src1.xy
2197 dst.zw = src0.zw \ src1.zw
2199 .. opcode:: U64DIV - 64-bit Unsigned Integer Division
2203 dst.xy = src0.xy \ src1.xy
2204 dst.zw = src0.zw \ src1.zw
2206 .. opcode:: U64MOD - 64-bit Unsigned Integer Remainder
2210 dst.xy = src0.xy \bmod src1.xy
2211 dst.zw = src0.zw \bmod src1.zw
2213 .. opcode:: I64MOD - 64-bit Signed Integer Remainder
2217 dst.xy = src0.xy \bmod src1.xy
2218 dst.zw = src0.zw \bmod src1.zw
2220 .. opcode:: F2U64 - Float to 64-bit Unsigned Int
2224 dst.xy = (uint64_t) src0.x
2225 dst.zw = (uint64_t) src0.y
2227 .. opcode:: F2I64 - Float to 64-bit Int
2231 dst.xy = (int64_t) src0.x
2232 dst.zw = (int64_t) src0.y
2234 .. opcode:: U2I64 - Unsigned Integer to 64-bit Integer
2236 This is a zero extension.
2240 dst.xy = (uint64_t) src0.x
2241 dst.zw = (uint64_t) src0.y
2243 .. opcode:: I2I64 - Signed Integer to 64-bit Integer
2245 This is a sign extension.
2249 dst.xy = (int64_t) src0.x
2250 dst.zw = (int64_t) src0.y
2252 .. opcode:: D2U64 - Double to 64-bit Unsigned Int
2256 dst.xy = (uint64_t) src0.xy
2257 dst.zw = (uint64_t) src0.zw
2259 .. opcode:: D2I64 - Double to 64-bit Int
2263 dst.xy = (int64_t) src0.xy
2264 dst.zw = (int64_t) src0.zw
2266 .. opcode:: U642F - 64-bit unsigned integer to float
2270 dst.x = (float) src0.xy
2271 dst.y = (float) src0.zw
2273 .. opcode:: I642F - 64-bit Int to Float
2277 dst.x = (float) src0.xy
2278 dst.y = (float) src0.zw
2280 .. opcode:: U642D - 64-bit unsigned integer to double
2284 dst.xy = (double) src0.xy
2285 dst.zw = (double) src0.zw
2287 .. opcode:: I642D - 64-bit Int to double
2291 dst.xy = (double) src0.xy
2292 dst.zw = (double) src0.zw
2294 .. _samplingopcodes:
2296 Resource Sampling Opcodes
2297 ^^^^^^^^^^^^^^^^^^^^^^^^^
2299 Those opcodes follow very closely semantics of the respective Direct3D
2300 instructions. If in doubt double check Direct3D documentation.
2301 Note that the swizzle on SVIEW (src1) determines texel swizzling
2306 Using provided address, sample data from the specified texture using the
2307 filtering mode identified by the given sampler. The source data may come from
2308 any resource type other than buffers.
2310 Syntax: ``SAMPLE dst, address, sampler_view, sampler``
2312 Example: ``SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]``
2314 .. opcode:: SAMPLE_I
2316 Simplified alternative to the SAMPLE instruction. Using the provided
2317 integer address, SAMPLE_I fetches data from the specified sampler view
2318 without any filtering. The source data may come from any resource type
2321 Syntax: ``SAMPLE_I dst, address, sampler_view``
2323 Example: ``SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]``
2325 The 'address' is specified as unsigned integers. If the 'address' is out of
2326 range [0...(# texels - 1)] the result of the fetch is always 0 in all
2327 components. As such the instruction doesn't honor address wrap modes, in
2328 cases where that behavior is desirable 'SAMPLE' instruction should be used.
2329 address.w always provides an unsigned integer mipmap level. If the value is
2330 out of the range then the instruction always returns 0 in all components.
2331 address.yz are ignored for buffers and 1d textures. address.z is ignored
2332 for 1d texture arrays and 2d textures.
2334 For 1D texture arrays address.y provides the array index (also as unsigned
2335 integer). If the value is out of the range of available array indices
2336 [0... (array size - 1)] then the opcode always returns 0 in all components.
2337 For 2D texture arrays address.z provides the array index, otherwise it
2338 exhibits the same behavior as in the case for 1D texture arrays. The exact
2339 semantics of the source address are presented in the table below:
2341 +---------------------------+----+-----+-----+---------+
2342 | resource type | X | Y | Z | W |
2343 +===========================+====+=====+=====+=========+
2344 | ``PIPE_BUFFER`` | x | | | ignored |
2345 +---------------------------+----+-----+-----+---------+
2346 | ``PIPE_TEXTURE_1D`` | x | | | mpl |
2347 +---------------------------+----+-----+-----+---------+
2348 | ``PIPE_TEXTURE_2D`` | x | y | | mpl |
2349 +---------------------------+----+-----+-----+---------+
2350 | ``PIPE_TEXTURE_3D`` | x | y | z | mpl |
2351 +---------------------------+----+-----+-----+---------+
2352 | ``PIPE_TEXTURE_RECT`` | x | y | | mpl |
2353 +---------------------------+----+-----+-----+---------+
2354 | ``PIPE_TEXTURE_CUBE`` | not allowed as source |
2355 +---------------------------+----+-----+-----+---------+
2356 | ``PIPE_TEXTURE_1D_ARRAY`` | x | idx | | mpl |
2357 +---------------------------+----+-----+-----+---------+
2358 | ``PIPE_TEXTURE_2D_ARRAY`` | x | y | idx | mpl |
2359 +---------------------------+----+-----+-----+---------+
2361 Where 'mpl' is a mipmap level and 'idx' is the array index.
2363 .. opcode:: SAMPLE_I_MS
2365 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2367 Syntax: ``SAMPLE_I_MS dst, address, sampler_view, sample``
2369 .. opcode:: SAMPLE_B
2371 Just like the SAMPLE instruction with the exception that an additional bias
2372 is applied to the level of detail computed as part of the instruction
2375 Syntax: ``SAMPLE_B dst, address, sampler_view, sampler, lod_bias``
2377 Example: ``SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2379 .. opcode:: SAMPLE_C
2381 Similar to the SAMPLE instruction but it performs a comparison filter. The
2382 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2383 additional float32 operand, reference value, which must be a register with
2384 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2385 current samplers compare_func (in pipe_sampler_state) to compare reference
2386 value against the red component value for the surce resource at each texel
2387 that the currently configured texture filter covers based on the provided
2390 Syntax: ``SAMPLE_C dst, address, sampler_view.r, sampler, ref_value``
2392 Example: ``SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2394 .. opcode:: SAMPLE_C_LZ
2396 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2399 Syntax: ``SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value``
2401 Example: ``SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2404 .. opcode:: SAMPLE_D
2406 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2407 the source address in the x direction and the y direction are provided by
2410 Syntax: ``SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y``
2412 Example: ``SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]``
2414 .. opcode:: SAMPLE_L
2416 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2417 directly as a scalar value, representing no anisotropy.
2419 Syntax: ``SAMPLE_L dst, address, sampler_view, sampler, explicit_lod``
2421 Example: ``SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2425 Gathers the four texels to be used in a bi-linear filtering operation and
2426 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2427 and cubemaps arrays. For 2D textures, only the addressing modes of the
2428 sampler and the top level of any mip pyramid are used. Set W to zero. It
2429 behaves like the SAMPLE instruction, but a filtered sample is not
2430 generated. The four samples that contribute to filtering are placed into
2431 xyzw in counter-clockwise order, starting with the (u,v) texture coordinate
2432 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2433 magnitude of the deltas are half a texel.
2436 .. opcode:: SVIEWINFO
2438 Query the dimensions of a given sampler view. dst receives width, height,
2439 depth or array size and number of mipmap levels as int4. The dst can have a
2440 writemask which will specify what info is the caller interested in.
2442 Syntax: ``SVIEWINFO dst, src_mip_level, sampler_view``
2444 Example: ``SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]``
2446 src_mip_level is an unsigned integer scalar. If it's out of range then
2447 returns 0 for width, height and depth/array size but the total number of
2448 mipmap is still returned correctly for the given sampler view. The returned
2449 width, height and depth values are for the mipmap level selected by the
2450 src_mip_level and are in the number of texels. For 1d texture array width
2451 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2452 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2453 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2454 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2455 resinfo allowing swizzling dst values is ignored (due to the interaction
2456 with rcpfloat modifier which requires some swizzle handling in the state
2459 .. opcode:: SAMPLE_POS
2461 Query the position of a given sample. dst receives float4 (x, y, 0, 0)
2462 indicated where the sample is located. If the resource is not a multi-sample
2463 resource and not a render target, the result is 0.
2465 .. opcode:: SAMPLE_INFO
2467 dst receives number of samples in x. If the resource is not a multi-sample
2468 resource and not a render target, the result is 0.
2471 .. _resourceopcodes:
2473 Resource Access Opcodes
2474 ^^^^^^^^^^^^^^^^^^^^^^^
2476 .. opcode:: LOAD - Fetch data from a shader buffer or image
2478 Syntax: ``LOAD dst, resource, address``
2480 Example: ``LOAD TEMP[0], BUFFER[0], TEMP[1]``
2482 Using the provided integer address, LOAD fetches data
2483 from the specified buffer or texture without any
2486 The 'address' is specified as a vector of unsigned
2487 integers. If the 'address' is out of range the result
2490 Only the first mipmap level of a resource can be read
2491 from using this instruction.
2493 For 1D or 2D texture arrays, the array index is
2494 provided as an unsigned integer in address.y or
2495 address.z, respectively. address.yz are ignored for
2496 buffers and 1D textures. address.z is ignored for 1D
2497 texture arrays and 2D textures. address.w is always
2500 A swizzle suffix may be added to the resource argument
2501 this will cause the resource data to be swizzled accordingly.
2503 .. opcode:: STORE - Write data to a shader resource
2505 Syntax: ``STORE resource, address, src``
2507 Example: ``STORE BUFFER[0], TEMP[0], TEMP[1]``
2509 Using the provided integer address, STORE writes data
2510 to the specified buffer or texture.
2512 The 'address' is specified as a vector of unsigned
2513 integers. If the 'address' is out of range the result
2516 Only the first mipmap level of a resource can be
2517 written to using this instruction.
2519 For 1D or 2D texture arrays, the array index is
2520 provided as an unsigned integer in address.y or
2521 address.z, respectively. address.yz are ignored for
2522 buffers and 1D textures. address.z is ignored for 1D
2523 texture arrays and 2D textures. address.w is always
2526 .. opcode:: RESQ - Query information about a resource
2528 Syntax: ``RESQ dst, resource``
2530 Example: ``RESQ TEMP[0], BUFFER[0]``
2532 Returns information about the buffer or image resource. For buffer
2533 resources, the size (in bytes) is returned in the x component. For
2534 image resources, .xyz will contain the width/height/layers of the
2535 image, while .w will contain the number of samples for multi-sampled
2538 .. opcode:: FBFETCH - Load data from framebuffer
2540 Syntax: ``FBFETCH dst, output``
2542 Example: ``FBFETCH TEMP[0], OUT[0]``
2544 This is only valid on ``COLOR`` semantic outputs. Returns the color
2545 of the current position in the framebuffer from before this fragment
2546 shader invocation. May return the same value from multiple calls for
2547 a particular output within a single invocation. Note that result may
2548 be undefined if a fragment is drawn multiple times without a blend
2552 .. _threadsyncopcodes:
2554 Inter-thread synchronization opcodes
2555 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2557 These opcodes are intended for communication between threads running
2558 within the same compute grid. For now they're only valid in compute
2561 .. opcode:: MFENCE - Memory fence
2563 Syntax: ``MFENCE resource``
2565 Example: ``MFENCE RES[0]``
2567 This opcode forces strong ordering between any memory access
2568 operations that affect the specified resource. This means that
2569 previous loads and stores (and only those) will be performed and
2570 visible to other threads before the program execution continues.
2573 .. opcode:: LFENCE - Load memory fence
2575 Syntax: ``LFENCE resource``
2577 Example: ``LFENCE RES[0]``
2579 Similar to MFENCE, but it only affects the ordering of memory loads.
2582 .. opcode:: SFENCE - Store memory fence
2584 Syntax: ``SFENCE resource``
2586 Example: ``SFENCE RES[0]``
2588 Similar to MFENCE, but it only affects the ordering of memory stores.
2591 .. opcode:: BARRIER - Thread group barrier
2595 This opcode suspends the execution of the current thread until all
2596 the remaining threads in the working group reach the same point of
2597 the program. Results are unspecified if any of the remaining
2598 threads terminates or never reaches an executed BARRIER instruction.
2600 .. opcode:: MEMBAR - Memory barrier
2604 This opcode waits for the completion of all memory accesses based on
2605 the type passed in. The type is an immediate bitfield with the following
2608 Bit 0: Shader storage buffers
2609 Bit 1: Atomic buffers
2611 Bit 3: Shared memory
2614 These may be passed in in any combination. An implementation is free to not
2615 distinguish between these as it sees fit. However these map to all the
2616 possibilities made available by GLSL.
2623 These opcodes provide atomic variants of some common arithmetic and
2624 logical operations. In this context atomicity means that another
2625 concurrent memory access operation that affects the same memory
2626 location is guaranteed to be performed strictly before or after the
2627 entire execution of the atomic operation. The resource may be a buffer
2628 or an image. In the case of an image, the offset works the same as for
2629 ``LOAD`` and ``STORE``, specified above. These atomic operations may
2630 only be used with 32-bit integer image formats.
2632 .. opcode:: ATOMUADD - Atomic integer addition
2634 Syntax: ``ATOMUADD dst, resource, offset, src``
2636 Example: ``ATOMUADD TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2638 The following operation is performed atomically:
2642 dst_x = resource[offset]
2644 resource[offset] = dst_x + src_x
2647 .. opcode:: ATOMXCHG - Atomic exchange
2649 Syntax: ``ATOMXCHG dst, resource, offset, src``
2651 Example: ``ATOMXCHG TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2653 The following operation is performed atomically:
2657 dst_x = resource[offset]
2659 resource[offset] = src_x
2662 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2664 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
2666 Example: ``ATOMCAS TEMP[0], BUFFER[0], TEMP[1], TEMP[2], TEMP[3]``
2668 The following operation is performed atomically:
2672 dst_x = resource[offset]
2674 resource[offset] = (dst_x == cmp_x ? src_x : dst_x)
2677 .. opcode:: ATOMAND - Atomic bitwise And
2679 Syntax: ``ATOMAND dst, resource, offset, src``
2681 Example: ``ATOMAND TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2683 The following operation is performed atomically:
2687 dst_x = resource[offset]
2689 resource[offset] = dst_x \& src_x
2692 .. opcode:: ATOMOR - Atomic bitwise Or
2694 Syntax: ``ATOMOR dst, resource, offset, src``
2696 Example: ``ATOMOR TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2698 The following operation is performed atomically:
2702 dst_x = resource[offset]
2704 resource[offset] = dst_x | src_x
2707 .. opcode:: ATOMXOR - Atomic bitwise Xor
2709 Syntax: ``ATOMXOR dst, resource, offset, src``
2711 Example: ``ATOMXOR TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2713 The following operation is performed atomically:
2717 dst_x = resource[offset]
2719 resource[offset] = dst_x \oplus src_x
2722 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2724 Syntax: ``ATOMUMIN dst, resource, offset, src``
2726 Example: ``ATOMUMIN TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2728 The following operation is performed atomically:
2732 dst_x = resource[offset]
2734 resource[offset] = (dst_x < src_x ? dst_x : src_x)
2737 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2739 Syntax: ``ATOMUMAX dst, resource, offset, src``
2741 Example: ``ATOMUMAX TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2743 The following operation is performed atomically:
2747 dst_x = resource[offset]
2749 resource[offset] = (dst_x > src_x ? dst_x : src_x)
2752 .. opcode:: ATOMIMIN - Atomic signed minimum
2754 Syntax: ``ATOMIMIN dst, resource, offset, src``
2756 Example: ``ATOMIMIN TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2758 The following operation is performed atomically:
2762 dst_x = resource[offset]
2764 resource[offset] = (dst_x < src_x ? dst_x : src_x)
2767 .. opcode:: ATOMIMAX - Atomic signed maximum
2769 Syntax: ``ATOMIMAX dst, resource, offset, src``
2771 Example: ``ATOMIMAX TEMP[0], BUFFER[0], TEMP[1], TEMP[2]``
2773 The following operation is performed atomically:
2777 dst_x = resource[offset]
2779 resource[offset] = (dst_x > src_x ? dst_x : src_x)
2787 These opcodes compare the given value across the shader invocations
2788 running in the current SIMD group. The details of exactly which
2789 invocations get compared are implementation-defined, and it would be a
2790 correct implementation to only ever consider the current thread's
2791 value. (i.e. SIMD group of 1). The argument is treated as a boolean.
2793 .. opcode:: VOTE_ANY - Value is set in any of the current invocations
2795 .. opcode:: VOTE_ALL - Value is set in all of the current invocations
2797 .. opcode:: VOTE_EQ - Value is the same in all of the current invocations
2800 Explanation of symbols used
2801 ------------------------------
2808 :math:`|x|` Absolute value of `x`.
2810 :math:`\lceil x \rceil` Ceiling of `x`.
2812 clamp(x,y,z) Clamp x between y and z.
2813 (x < y) ? y : (x > z) ? z : x
2815 :math:`\lfloor x\rfloor` Floor of `x`.
2817 :math:`\log_2{x}` Logarithm of `x`, base 2.
2819 max(x,y) Maximum of x and y.
2822 min(x,y) Minimum of x and y.
2825 partialx(x) Derivative of x relative to fragment's X.
2827 partialy(x) Derivative of x relative to fragment's Y.
2829 pop() Pop from stack.
2831 :math:`x^y` `x` to the power `y`.
2833 push(x) Push x on stack.
2837 trunc(x) Truncate x, i.e. drop the fraction bits.
2844 discard Discard fragment.
2848 target Label of target instruction.
2859 Declares a register that is will be referenced as an operand in Instruction
2862 File field contains register file that is being declared and is one
2865 UsageMask field specifies which of the register components can be accessed
2866 and is one of TGSI_WRITEMASK.
2868 The Local flag specifies that a given value isn't intended for
2869 subroutine parameter passing and, as a result, the implementation
2870 isn't required to give any guarantees of it being preserved across
2871 subroutine boundaries. As it's merely a compiler hint, the
2872 implementation is free to ignore it.
2874 If Dimension flag is set to 1, a Declaration Dimension token follows.
2876 If Semantic flag is set to 1, a Declaration Semantic token follows.
2878 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
2880 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
2882 If Array flag is set to 1, a Declaration Array token follows.
2885 ^^^^^^^^^^^^^^^^^^^^^^^^
2887 Declarations can optional have an ArrayID attribute which can be referred by
2888 indirect addressing operands. An ArrayID of zero is reserved and treated as
2889 if no ArrayID is specified.
2891 If an indirect addressing operand refers to a specific declaration by using
2892 an ArrayID only the registers in this declaration are guaranteed to be
2893 accessed, accessing any register outside this declaration results in undefined
2894 behavior. Note that for compatibility the effective index is zero-based and
2895 not relative to the specified declaration
2897 If no ArrayID is specified with an indirect addressing operand the whole
2898 register file might be accessed by this operand. This is strongly discouraged
2899 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
2900 This is only legal for TEMP and CONST register files.
2902 Declaration Semantic
2903 ^^^^^^^^^^^^^^^^^^^^^^^^
2905 Vertex and fragment shader input and output registers may be labeled
2906 with semantic information consisting of a name and index.
2908 Follows Declaration token if Semantic bit is set.
2910 Since its purpose is to link a shader with other stages of the pipeline,
2911 it is valid to follow only those Declaration tokens that declare a register
2912 either in INPUT or OUTPUT file.
2914 SemanticName field contains the semantic name of the register being declared.
2915 There is no default value.
2917 SemanticIndex is an optional subscript that can be used to distinguish
2918 different register declarations with the same semantic name. The default value
2921 The meanings of the individual semantic names are explained in the following
2924 TGSI_SEMANTIC_POSITION
2925 """"""""""""""""""""""
2927 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
2928 output register which contains the homogeneous vertex position in the clip
2929 space coordinate system. After clipping, the X, Y and Z components of the
2930 vertex will be divided by the W value to get normalized device coordinates.
2932 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
2933 fragment shader input (or system value, depending on which one is
2934 supported by the driver) contains the fragment's window position. The X
2935 component starts at zero and always increases from left to right.
2936 The Y component starts at zero and always increases but Y=0 may either
2937 indicate the top of the window or the bottom depending on the fragment
2938 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
2939 The Z coordinate ranges from 0 to 1 to represent depth from the front
2940 to the back of the Z buffer. The W component contains the interpolated
2941 reciprocal of the vertex position W component (corresponding to gl_Fragcoord,
2942 but unlike d3d10 which interpolates the same 1/w but then gives back
2943 the reciprocal of the interpolated value).
2945 Fragment shaders may also declare an output register with
2946 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
2947 the fragment shader to change the fragment's Z position.
2954 For vertex shader outputs or fragment shader inputs/outputs, this
2955 label indicates that the register contains an R,G,B,A color.
2957 Several shader inputs/outputs may contain colors so the semantic index
2958 is used to distinguish them. For example, color[0] may be the diffuse
2959 color while color[1] may be the specular color.
2961 This label is needed so that the flat/smooth shading can be applied
2962 to the right interpolants during rasterization.
2966 TGSI_SEMANTIC_BCOLOR
2967 """"""""""""""""""""
2969 Back-facing colors are only used for back-facing polygons, and are only valid
2970 in vertex shader outputs. After rasterization, all polygons are front-facing
2971 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
2972 so all BCOLORs effectively become regular COLORs in the fragment shader.
2978 Vertex shader inputs and outputs and fragment shader inputs may be
2979 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
2980 a fog coordinate. Typically, the fragment shader will use the fog coordinate
2981 to compute a fog blend factor which is used to blend the normal fragment color
2982 with a constant fog color. But fog coord really is just an ordinary vec4
2983 register like regular semantics.
2989 Vertex shader input and output registers may be labeled with
2990 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
2991 in the form (S, 0, 0, 1). The point size controls the width or diameter
2992 of points for rasterization. This label cannot be used in fragment
2995 When using this semantic, be sure to set the appropriate state in the
2996 :ref:`rasterizer` first.
2999 TGSI_SEMANTIC_TEXCOORD
3000 """"""""""""""""""""""
3002 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
3004 Vertex shader outputs and fragment shader inputs may be labeled with
3005 this semantic to make them replaceable by sprite coordinates via the
3006 sprite_coord_enable state in the :ref:`rasterizer`.
3007 The semantic index permitted with this semantic is limited to <= 7.
3009 If the driver does not support TEXCOORD, sprite coordinate replacement
3010 applies to inputs with the GENERIC semantic instead.
3012 The intended use case for this semantic is gl_TexCoord.
3015 TGSI_SEMANTIC_PCOORD
3016 """"""""""""""""""""
3018 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
3020 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
3021 that the register contains sprite coordinates in the form (x, y, 0, 1), if
3022 the current primitive is a point and point sprites are enabled. Otherwise,
3023 the contents of the register are undefined.
3025 The intended use case for this semantic is gl_PointCoord.
3028 TGSI_SEMANTIC_GENERIC
3029 """""""""""""""""""""
3031 All vertex/fragment shader inputs/outputs not labeled with any other
3032 semantic label can be considered to be generic attributes. Typical
3033 uses of generic inputs/outputs are texcoords and user-defined values.
3036 TGSI_SEMANTIC_NORMAL
3037 """"""""""""""""""""
3039 Indicates that a vertex shader input is a normal vector. This is
3040 typically only used for legacy graphics APIs.
3046 This label applies to fragment shader inputs (or system values,
3047 depending on which one is supported by the driver) and indicates that
3048 the register contains front/back-face information.
3050 If it is an input, it will be a floating-point vector in the form (F, 0, 0, 1),
3051 where F will be positive when the fragment belongs to a front-facing polygon,
3052 and negative when the fragment belongs to a back-facing polygon.
3054 If it is a system value, it will be an integer vector in the form (F, 0, 0, 1),
3055 where F is 0xffffffff when the fragment belongs to a front-facing polygon and
3056 0 when the fragment belongs to a back-facing polygon.
3059 TGSI_SEMANTIC_EDGEFLAG
3060 """"""""""""""""""""""
3062 For vertex shaders, this sematic label indicates that an input or
3063 output is a boolean edge flag. The register layout is [F, x, x, x]
3064 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
3065 simply copies the edge flag input to the edgeflag output.
3067 Edge flags are used to control which lines or points are actually
3068 drawn when the polygon mode converts triangles/quads/polygons into
3072 TGSI_SEMANTIC_STENCIL
3073 """""""""""""""""""""
3075 For fragment shaders, this semantic label indicates that an output
3076 is a writable stencil reference value. Only the Y component is writable.
3077 This allows the fragment shader to change the fragments stencilref value.
3080 TGSI_SEMANTIC_VIEWPORT_INDEX
3081 """"""""""""""""""""""""""""
3083 For geometry shaders, this semantic label indicates that an output
3084 contains the index of the viewport (and scissor) to use.
3085 This is an integer value, and only the X component is used.
3091 For geometry shaders, this semantic label indicates that an output
3092 contains the layer value to use for the color and depth/stencil surfaces.
3093 This is an integer value, and only the X component is used.
3094 (Also known as rendertarget array index.)
3097 TGSI_SEMANTIC_CULLDIST
3098 """"""""""""""""""""""
3100 Used as distance to plane for performing application-defined culling
3101 of individual primitives against a plane. When components of vertex
3102 elements are given this label, these values are assumed to be a
3103 float32 signed distance to a plane. Primitives will be completely
3104 discarded if the plane distance for all of the vertices in the
3105 primitive are < 0. If a vertex has a cull distance of NaN, that
3106 vertex counts as "out" (as if its < 0);
3107 The limits on both clip and cull distances are bound
3108 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
3109 the maximum number of components that can be used to hold the
3110 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
3111 which specifies the maximum number of registers which can be
3112 annotated with those semantics.
3115 TGSI_SEMANTIC_CLIPDIST
3116 """"""""""""""""""""""
3118 Note this covers clipping and culling distances.
3120 When components of vertex elements are identified this way, these
3121 values are each assumed to be a float32 signed distance to a plane.
3124 Primitive setup only invokes rasterization on pixels for which
3125 the interpolated plane distances are >= 0.
3128 Primitives will be completely discarded if the plane distance
3129 for all of the vertices in the primitive are < 0.
3130 If a vertex has a cull distance of NaN, that vertex counts as "out"
3133 Multiple clip/cull planes can be implemented simultaneously, by
3134 annotating multiple components of one or more vertex elements with
3135 the above specified semantic.
3136 The limits on both clip and cull distances are bound
3137 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
3138 the maximum number of components that can be used to hold the
3139 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
3140 which specifies the maximum number of registers which can be
3141 annotated with those semantics.
3142 The properties NUM_CLIPDIST_ENABLED and NUM_CULLDIST_ENABLED
3143 are used to divide up the 2 x vec4 space between clipping and culling.
3145 TGSI_SEMANTIC_SAMPLEID
3146 """"""""""""""""""""""
3148 For fragment shaders, this semantic label indicates that a system value
3149 contains the current sample id (i.e. gl_SampleID).
3150 This is an integer value, and only the X component is used.
3152 TGSI_SEMANTIC_SAMPLEPOS
3153 """""""""""""""""""""""
3155 For fragment shaders, this semantic label indicates that a system value
3156 contains the current sample's position (i.e. gl_SamplePosition). Only the X
3157 and Y values are used.
3159 TGSI_SEMANTIC_SAMPLEMASK
3160 """"""""""""""""""""""""
3162 For fragment shaders, this semantic label indicates that an output contains
3163 the sample mask used to disable further sample processing
3164 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
3166 TGSI_SEMANTIC_INVOCATIONID
3167 """"""""""""""""""""""""""
3169 For geometry shaders, this semantic label indicates that a system value
3170 contains the current invocation id (i.e. gl_InvocationID).
3171 This is an integer value, and only the X component is used.
3173 TGSI_SEMANTIC_INSTANCEID
3174 """"""""""""""""""""""""
3176 For vertex shaders, this semantic label indicates that a system value contains
3177 the current instance id (i.e. gl_InstanceID). It does not include the base
3178 instance. This is an integer value, and only the X component is used.
3180 TGSI_SEMANTIC_VERTEXID
3181 """"""""""""""""""""""
3183 For vertex shaders, this semantic label indicates that a system value contains
3184 the current vertex id (i.e. gl_VertexID). It does (unlike in d3d10) include the
3185 base vertex. This is an integer value, and only the X component is used.
3187 TGSI_SEMANTIC_VERTEXID_NOBASE
3188 """""""""""""""""""""""""""""""
3190 For vertex shaders, this semantic label indicates that a system value contains
3191 the current vertex id without including the base vertex (this corresponds to
3192 d3d10 vertex id, so TGSI_SEMANTIC_VERTEXID_NOBASE + TGSI_SEMANTIC_BASEVERTEX
3193 == TGSI_SEMANTIC_VERTEXID). This is an integer value, and only the X component
3196 TGSI_SEMANTIC_BASEVERTEX
3197 """"""""""""""""""""""""
3199 For vertex shaders, this semantic label indicates that a system value contains
3200 the base vertex (i.e. gl_BaseVertex). Note that for non-indexed draw calls,
3201 this contains the first (or start) value instead.
3202 This is an integer value, and only the X component is used.
3204 TGSI_SEMANTIC_PRIMID
3205 """"""""""""""""""""
3207 For geometry and fragment shaders, this semantic label indicates the value
3208 contains the primitive id (i.e. gl_PrimitiveID). This is an integer value,
3209 and only the X component is used.
3210 FIXME: This right now can be either a ordinary input or a system value...
3216 For tessellation evaluation/control shaders, this semantic label indicates a
3217 generic per-patch attribute. Such semantics will not implicitly be per-vertex
3220 TGSI_SEMANTIC_TESSCOORD
3221 """""""""""""""""""""""
3223 For tessellation evaluation shaders, this semantic label indicates the
3224 coordinates of the vertex being processed. This is available in XYZ; W is
3227 TGSI_SEMANTIC_TESSOUTER
3228 """""""""""""""""""""""
3230 For tessellation evaluation/control shaders, this semantic label indicates the
3231 outer tessellation levels of the patch. Isoline tessellation will only have XY
3232 defined, triangle will have XYZ and quads will have XYZW defined. This
3233 corresponds to gl_TessLevelOuter.
3235 TGSI_SEMANTIC_TESSINNER
3236 """""""""""""""""""""""
3238 For tessellation evaluation/control shaders, this semantic label indicates the
3239 inner tessellation levels of the patch. The X value is only defined for
3240 triangle tessellation, while quads will have XY defined. This is entirely
3241 undefined for isoline tessellation.
3243 TGSI_SEMANTIC_VERTICESIN
3244 """"""""""""""""""""""""
3246 For tessellation evaluation/control shaders, this semantic label indicates the
3247 number of vertices provided in the input patch. Only the X value is defined.
3249 TGSI_SEMANTIC_HELPER_INVOCATION
3250 """""""""""""""""""""""""""""""
3252 For fragment shaders, this semantic indicates whether the current
3253 invocation is covered or not. Helper invocations are created in order
3254 to properly compute derivatives, however it may be desirable to skip
3255 some of the logic in those cases. See ``gl_HelperInvocation`` documentation.
3257 TGSI_SEMANTIC_BASEINSTANCE
3258 """"""""""""""""""""""""""
3260 For vertex shaders, the base instance argument supplied for this
3261 draw. This is an integer value, and only the X component is used.
3263 TGSI_SEMANTIC_DRAWID
3264 """"""""""""""""""""
3266 For vertex shaders, the zero-based index of the current draw in a
3267 ``glMultiDraw*`` invocation. This is an integer value, and only the X
3271 TGSI_SEMANTIC_WORK_DIM
3272 """"""""""""""""""""""
3274 For compute shaders started via opencl this retrieves the work_dim
3275 parameter to the clEnqueueNDRangeKernel call with which the shader
3279 TGSI_SEMANTIC_GRID_SIZE
3280 """""""""""""""""""""""
3282 For compute shaders, this semantic indicates the maximum (x, y, z) dimensions
3283 of a grid of thread blocks.
3286 TGSI_SEMANTIC_BLOCK_ID
3287 """"""""""""""""""""""
3289 For compute shaders, this semantic indicates the (x, y, z) coordinates of the
3290 current block inside of the grid.
3293 TGSI_SEMANTIC_BLOCK_SIZE
3294 """"""""""""""""""""""""
3296 For compute shaders, this semantic indicates the maximum (x, y, z) dimensions
3297 of a block in threads.
3300 TGSI_SEMANTIC_THREAD_ID
3301 """""""""""""""""""""""
3303 For compute shaders, this semantic indicates the (x, y, z) coordinates of the
3304 current thread inside of the block.
3307 Declaration Interpolate
3308 ^^^^^^^^^^^^^^^^^^^^^^^
3310 This token is only valid for fragment shader INPUT declarations.
3312 The Interpolate field specifes the way input is being interpolated by
3313 the rasteriser and is one of TGSI_INTERPOLATE_*.
3315 The Location field specifies the location inside the pixel that the
3316 interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
3317 when per-sample shading is enabled, the implementation may choose to
3318 interpolate at the sample irrespective of the Location field.
3320 The CylindricalWrap bitfield specifies which register components
3321 should be subject to cylindrical wrapping when interpolating by the
3322 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
3323 should be interpolated according to cylindrical wrapping rules.
3326 Declaration Sampler View
3327 ^^^^^^^^^^^^^^^^^^^^^^^^
3329 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
3331 DCL SVIEW[#], resource, type(s)
3333 Declares a shader input sampler view and assigns it to a SVIEW[#]
3336 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
3338 type must be 1 or 4 entries (if specifying on a per-component
3339 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
3341 For TEX\* style texture sample opcodes (as opposed to SAMPLE\* opcodes
3342 which take an explicit SVIEW[#] source register), there may be optionally
3343 SVIEW[#] declarations. In this case, the SVIEW index is implied by the
3344 SAMP index, and there must be a corresponding SVIEW[#] declaration for
3345 each SAMP[#] declaration. Drivers are free to ignore this if they wish.
3346 But note in particular that some drivers need to know the sampler type
3347 (float/int/unsigned) in order to generate the correct code, so cases
3348 where integer textures are sampled, SVIEW[#] declarations should be
3351 NOTE: It is NOT legal to mix SAMPLE\* style opcodes and TEX\* opcodes
3354 Declaration Resource
3355 ^^^^^^^^^^^^^^^^^^^^
3357 Follows Declaration token if file is TGSI_FILE_RESOURCE.
3359 DCL RES[#], resource [, WR] [, RAW]
3361 Declares a shader input resource and assigns it to a RES[#]
3364 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
3367 If the RAW keyword is not specified, the texture data will be
3368 subject to conversion, swizzling and scaling as required to yield
3369 the specified data type from the physical data format of the bound
3372 If the RAW keyword is specified, no channel conversion will be
3373 performed: the values read for each of the channels (X,Y,Z,W) will
3374 correspond to consecutive words in the same order and format
3375 they're found in memory. No element-to-address conversion will be
3376 performed either: the value of the provided X coordinate will be
3377 interpreted in byte units instead of texel units. The result of
3378 accessing a misaligned address is undefined.
3380 Usage of the STORE opcode is only allowed if the WR (writable) flag
3385 ^^^^^^^^^^^^^^^^^^^^^^^^
3387 Properties are general directives that apply to the whole TGSI program.
3392 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
3393 The default value is UPPER_LEFT.
3395 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
3396 increase downward and rightward.
3397 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
3398 increase upward and rightward.
3400 OpenGL defaults to LOWER_LEFT, and is configurable with the
3401 GL_ARB_fragment_coord_conventions extension.
3403 DirectX 9/10 use UPPER_LEFT.
3405 FS_COORD_PIXEL_CENTER
3406 """""""""""""""""""""
3408 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
3409 The default value is HALF_INTEGER.
3411 If HALF_INTEGER, the fractionary part of the position will be 0.5
3412 If INTEGER, the fractionary part of the position will be 0.0
3414 Note that this does not affect the set of fragments generated by
3415 rasterization, which is instead controlled by half_pixel_center in the
3418 OpenGL defaults to HALF_INTEGER, and is configurable with the
3419 GL_ARB_fragment_coord_conventions extension.
3421 DirectX 9 uses INTEGER.
3422 DirectX 10 uses HALF_INTEGER.
3424 FS_COLOR0_WRITES_ALL_CBUFS
3425 """"""""""""""""""""""""""
3426 Specifies that writes to the fragment shader color 0 are replicated to all
3427 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
3428 fragData is directed to a single color buffer, but fragColor is broadcast.
3431 """"""""""""""""""""""""""
3432 If this property is set on the program bound to the shader stage before the
3433 fragment shader, user clip planes should have no effect (be disabled) even if
3434 that shader does not write to any clip distance outputs and the rasterizer's
3435 clip_plane_enable is non-zero.
3436 This property is only supported by drivers that also support shader clip
3438 This is useful for APIs that don't have UCPs and where clip distances written
3439 by a shader cannot be disabled.
3444 Specifies the number of times a geometry shader should be executed for each
3445 input primitive. Each invocation will have a different
3446 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
3449 VS_WINDOW_SPACE_POSITION
3450 """"""""""""""""""""""""""
3451 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
3452 is assumed to contain window space coordinates.
3453 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
3454 directly taken from the 4-th component of the shader output.
3455 Naturally, clipping is not performed on window coordinates either.
3456 The effect of this property is undefined if a geometry or tessellation shader
3462 The number of vertices written by the tessellation control shader. This
3463 effectively defines the patch input size of the tessellation evaluation shader
3469 This sets the tessellation primitive mode, one of ``PIPE_PRIM_TRIANGLES``,
3470 ``PIPE_PRIM_QUADS``, or ``PIPE_PRIM_LINES``. (Unlike in GL, there is no
3471 separate isolines settings, the regular lines is assumed to mean isolines.)
3476 This sets the spacing mode of the tessellation generator, one of
3477 ``PIPE_TESS_SPACING_*``.
3482 This sets the vertex order to be clockwise if the value is 1, or
3483 counter-clockwise if set to 0.
3488 If set to a non-zero value, this turns on point mode for the tessellator,
3489 which means that points will be generated instead of primitives.
3491 NUM_CLIPDIST_ENABLED
3494 How many clip distance scalar outputs are enabled.
3496 NUM_CULLDIST_ENABLED
3499 How many cull distance scalar outputs are enabled.
3501 FS_EARLY_DEPTH_STENCIL
3502 """"""""""""""""""""""
3504 Whether depth test, stencil test, and occlusion query should run before
3505 the fragment shader (regardless of fragment shader side effects). Corresponds
3506 to GLSL early_fragment_tests.
3511 Which shader stage will MOST LIKELY follow after this shader when the shader
3512 is bound. This is only a hint to the driver and doesn't have to be precise.
3513 Only set for VS and TES.
3515 CS_FIXED_BLOCK_WIDTH / HEIGHT / DEPTH
3516 """""""""""""""""""""""""""""""""""""
3518 Threads per block in each dimension, if known at compile time. If the block size
3519 is known all three should be at least 1. If it is unknown they should all be set
3525 The MUL TGSI operation (FP32 multiplication) will return 0 if either
3526 of the operands are equal to 0. That means that 0 * Inf = 0. This
3527 should be set the same way for an entire pipeline. Note that this
3528 applies not only to the literal MUL TGSI opcode, but all FP32
3529 multiplications implied by other operations, such as MAD, FMA, DP2,
3530 DP3, DP4, DPH, DST, LOG, LRP, XPD, and possibly others. If there is a
3531 mismatch between shaders, then it is unspecified whether this behavior
3535 Texture Sampling and Texture Formats
3536 ------------------------------------
3538 This table shows how texture image components are returned as (x,y,z,w) tuples
3539 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
3540 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
3543 +--------------------+--------------+--------------------+--------------+
3544 | Texture Components | Gallium | OpenGL | Direct3D 9 |
3545 +====================+==============+====================+==============+
3546 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
3547 +--------------------+--------------+--------------------+--------------+
3548 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
3549 +--------------------+--------------+--------------------+--------------+
3550 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
3551 +--------------------+--------------+--------------------+--------------+
3552 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
3553 +--------------------+--------------+--------------------+--------------+
3554 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
3555 +--------------------+--------------+--------------------+--------------+
3556 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
3557 +--------------------+--------------+--------------------+--------------+
3558 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
3559 +--------------------+--------------+--------------------+--------------+
3560 | I | (i, i, i, i) | (i, i, i, i) | N/A |
3561 +--------------------+--------------+--------------------+--------------+
3562 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
3563 | | | [#envmap-bumpmap]_ | |
3564 +--------------------+--------------+--------------------+--------------+
3565 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
3566 | | | [#depth-tex-mode]_ | |
3567 +--------------------+--------------+--------------------+--------------+
3568 | S | (s, s, s, s) | unknown | unknown |
3569 +--------------------+--------------+--------------------+--------------+
3571 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
3572 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
3573 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.