an important part of the API. TGSI is the only intermediate representation
used by all drivers.
+Basics
+------
+
+All TGSI instructions, known as *opcodes*, operate on arbitrary-precision
+floating-point four-component vectors. An opcode may have up to one
+destination register, known as *dst*, and between zero and three source
+registers, called *src0* through *src2*, or simply *src* if there is only
+one.
+
+Some instructions, like :opcode:`I2F`, permit re-interpretation of vector
+components as integers. Other instructions permit using registers as
+two-component vectors with double precision; see :ref:`Double Opcodes`.
+
+When an instruction has a scalar result, the result is usually copied into
+each of the components of *dst*. When this happens, the result is said to be
+*replicated* to *dst*. :opcode:`RCP` is one such instruction.
+
Instruction Set
---------------
^^^^^^^^^^^^^^^^^^^^^^^^^
-ARL - Address Register Load
+.. opcode:: ARL - Address Register Load
.. math::
dst.w = \lfloor src.w\rfloor
-MOV - Move
+.. opcode:: MOV - Move
.. math::
dst.w = src.w
-LIT - Light Coefficients
+.. opcode:: LIT - Light Coefficients
.. math::
dst.w = 1
-RCP - Reciprocal
-
-.. math::
+.. opcode:: RCP - Reciprocal
- dst.x = \frac{1}{src.x}
+This instruction replicates its result.
- dst.y = \frac{1}{src.x}
+.. math::
- dst.z = \frac{1}{src.x}
+ dst = \frac{1}{src.x}
- dst.w = \frac{1}{src.x}
+.. opcode:: RSQ - Reciprocal Square Root
-RSQ - Reciprocal Square Root
+This instruction replicates its result.
.. math::
- dst.x = \frac{1}{\sqrt{|src.x|}}
-
- dst.y = \frac{1}{\sqrt{|src.x|}}
-
- dst.z = \frac{1}{\sqrt{|src.x|}}
+ dst = \frac{1}{\sqrt{|src.x|}}
- dst.w = \frac{1}{\sqrt{|src.x|}}
-
-EXP - Approximate Exponential Base 2
+.. opcode:: EXP - Approximate Exponential Base 2
.. math::
dst.w = 1
-LOG - Approximate Logarithm Base 2
+.. opcode:: LOG - Approximate Logarithm Base 2
.. math::
dst.w = 1
-MUL - Multiply
+.. opcode:: MUL - Multiply
.. math::
dst.w = src0.w \times src1.w
-ADD - Add
+.. opcode:: ADD - Add
.. math::
dst.w = src0.w + src1.w
-DP3 - 3-component Dot Product
-
-.. math::
+.. opcode:: DP3 - 3-component Dot Product
- dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+This instruction replicates its result.
- dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+.. math::
- dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+ dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
- dst.w = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+.. opcode:: DP4 - 4-component Dot Product
-DP4 - 4-component Dot Product
+This instruction replicates its result.
.. math::
- dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
-
- dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
-
- dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
+ dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
- dst.w = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
-
-DST - Distance Vector
+.. opcode:: DST - Distance Vector
.. math::
dst.w = src1.w
-MIN - Minimum
+.. opcode:: MIN - Minimum
.. math::
dst.w = min(src0.w, src1.w)
-MAX - Maximum
+.. opcode:: MAX - Maximum
.. math::
dst.w = max(src0.w, src1.w)
-SLT - Set On Less Than
+.. opcode:: SLT - Set On Less Than
.. math::
dst.w = (src0.w < src1.w) ? 1 : 0
-SGE - Set On Greater Equal Than
+.. opcode:: SGE - Set On Greater Equal Than
.. math::
dst.w = (src0.w >= src1.w) ? 1 : 0
-MAD - Multiply And Add
+.. opcode:: MAD - Multiply And Add
.. math::
dst.w = src0.w \times src1.w + src2.w
-SUB - Subtract
+.. opcode:: SUB - Subtract
.. math::
dst.w = src0.w - src1.w
-LRP - Linear Interpolate
+.. opcode:: LRP - Linear Interpolate
.. math::
dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
-CND - Condition
+.. opcode:: CND - Condition
.. math::
dst.w = (src2.w > 0.5) ? src0.w : src1.w
-DP2A - 2-component Dot Product And Add
+.. opcode:: DP2A - 2-component Dot Product And Add
.. math::
dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x
-FRAC - Fraction
+.. opcode:: FRAC - Fraction
.. math::
dst.w = src.w - \lfloor src.w\rfloor
-CLAMP - Clamp
+.. opcode:: CLAMP - Clamp
.. math::
dst.w = clamp(src0.w, src1.w, src2.w)
-FLR - Floor
+.. opcode:: FLR - Floor
-This is identical to ARL.
+This is identical to :opcode:`ARL`.
.. math::
dst.w = \lfloor src.w\rfloor
-ROUND - Round
+.. opcode:: ROUND - Round
.. math::
dst.w = round(src.w)
-EX2 - Exponential Base 2
-
-.. math::
+.. opcode:: EX2 - Exponential Base 2
- dst.x = 2^{src.x}
+This instruction replicates its result.
- dst.y = 2^{src.x}
+.. math::
- dst.z = 2^{src.x}
+ dst = 2^{src.x}
- dst.w = 2^{src.x}
+.. opcode:: LG2 - Logarithm Base 2
-LG2 - Logarithm Base 2
+This instruction replicates its result.
.. math::
- dst.x = \log_2{src.x}
-
- dst.y = \log_2{src.x}
+ dst = \log_2{src.x}
- dst.z = \log_2{src.x}
- dst.w = \log_2{src.x}
+.. opcode:: POW - Power
-
-POW - Power
+This instruction replicates its result.
.. math::
- dst.x = src0.x^{src1.x}
-
- dst.y = src0.x^{src1.x}
-
- dst.z = src0.x^{src1.x}
+ dst = src0.x^{src1.x}
- dst.w = src0.x^{src1.x}
-
-XPD - Cross Product
+.. opcode:: XPD - Cross Product
.. math::
dst.w = 1
-ABS - Absolute
+.. opcode:: ABS - Absolute
.. math::
dst.w = |src.w|
-RCC - Reciprocal Clamped
+.. opcode:: RCC - Reciprocal Clamped
+
+This instruction replicates its result.
XXX cleanup on aisle three
.. math::
- dst.x = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
-
- dst.y = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
+ dst = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
- dst.z = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
- dst.w = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
+.. opcode:: DPH - Homogeneous Dot Product
-
-DPH - Homogeneous Dot Product
+This instruction replicates its result.
.. math::
- dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
-
- dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
-
- dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
+ dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
- dst.w = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
+.. opcode:: COS - Cosine
-COS - Cosine
+This instruction replicates its result.
.. math::
- dst.x = \cos{src.x}
-
- dst.y = \cos{src.x}
-
- dst.z = \cos{src.x}
+ dst = \cos{src.x}
- dst.w = \cos{src.x}
-
-DDX - Derivative Relative To X
+.. opcode:: DDX - Derivative Relative To X
.. math::
dst.w = partialx(src.w)
-DDY - Derivative Relative To Y
+.. opcode:: DDY - Derivative Relative To Y
.. math::
dst.w = partialy(src.w)
-KILP - Predicated Discard
+.. opcode:: KILP - Predicated Discard
discard
-PK2H - Pack Two 16-bit Floats
+.. opcode:: PK2H - Pack Two 16-bit Floats
TBD
-PK2US - Pack Two Unsigned 16-bit Scalars
+.. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
TBD
-PK4B - Pack Four Signed 8-bit Scalars
+.. opcode:: PK4B - Pack Four Signed 8-bit Scalars
TBD
-PK4UB - Pack Four Unsigned 8-bit Scalars
+.. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
TBD
-RFL - Reflection Vector
+.. opcode:: RFL - Reflection Vector
.. math::
dst.w = 1
-Considered for removal.
+.. note::
+
+ Considered for removal.
-SEQ - Set On Equal
+.. opcode:: SEQ - Set On Equal
.. math::
dst.x = (src0.x == src1.x) ? 1 : 0
+
dst.y = (src0.y == src1.y) ? 1 : 0
+
dst.z = (src0.z == src1.z) ? 1 : 0
+
dst.w = (src0.w == src1.w) ? 1 : 0
-SFL - Set On False
+.. opcode:: SFL - Set On False
+
+This instruction replicates its result.
.. math::
- dst.x = 0
- dst.y = 0
- dst.z = 0
- dst.w = 0
+ dst = 0
+
+.. note::
+
+ Considered for removal.
-Considered for removal.
-SGT - Set On Greater Than
+.. opcode:: SGT - Set On Greater Than
.. math::
dst.x = (src0.x > src1.x) ? 1 : 0
+
dst.y = (src0.y > src1.y) ? 1 : 0
- dst.z = (src0.z > src1.z) ? 1 : 0
- dst.w = (src0.w > src1.w) ? 1 : 0
+ dst.z = (src0.z > src1.z) ? 1 : 0
-SIN - Sine
+ dst.w = (src0.w > src1.w) ? 1 : 0
-.. math::
- dst.x = \sin{src.x}
+.. opcode:: SIN - Sine
- dst.y = \sin{src.x}
+This instruction replicates its result.
- dst.z = \sin{src.x}
+.. math::
- dst.w = \sin{src.x}
+ dst = \sin{src.x}
-SLE - Set On Less Equal Than
+.. opcode:: SLE - Set On Less Equal Than
.. math::
dst.x = (src0.x <= src1.x) ? 1 : 0
+
dst.y = (src0.y <= src1.y) ? 1 : 0
+
dst.z = (src0.z <= src1.z) ? 1 : 0
+
dst.w = (src0.w <= src1.w) ? 1 : 0
-SNE - Set On Not Equal
+.. opcode:: SNE - Set On Not Equal
.. math::
dst.x = (src0.x != src1.x) ? 1 : 0
+
dst.y = (src0.y != src1.y) ? 1 : 0
+
dst.z = (src0.z != src1.z) ? 1 : 0
+
dst.w = (src0.w != src1.w) ? 1 : 0
-STR - Set On True
+.. opcode:: STR - Set On True
+
+This instruction replicates its result.
.. math::
- dst.x = 1
- dst.y = 1
- dst.z = 1
- dst.w = 1
+ dst = 1
-TEX - Texture Lookup
+.. opcode:: TEX - Texture Lookup
TBD
-TXD - Texture Lookup with Derivatives
+.. opcode:: TXD - Texture Lookup with Derivatives
TBD
-TXP - Projective Texture Lookup
+.. opcode:: TXP - Projective Texture Lookup
TBD
-UP2H - Unpack Two 16-Bit Floats
+.. opcode:: UP2H - Unpack Two 16-Bit Floats
TBD
- Considered for removal.
+.. note::
+
+ Considered for removal.
-UP2US - Unpack Two Unsigned 16-Bit Scalars
+.. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
TBD
- Considered for removal.
+.. note::
+
+ Considered for removal.
-UP4B - Unpack Four Signed 8-Bit Values
+.. opcode:: UP4B - Unpack Four Signed 8-Bit Values
TBD
- Considered for removal.
+.. note::
-UP4UB - Unpack Four Unsigned 8-Bit Scalars
+ Considered for removal.
+
+.. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
TBD
- Considered for removal.
+.. note::
+
+ Considered for removal.
-X2D - 2D Coordinate Transformation
+.. opcode:: X2D - 2D Coordinate Transformation
.. math::
dst.x = src0.x + src1.x \times src2.x + src1.y \times src2.y
+
dst.y = src0.y + src1.x \times src2.z + src1.y \times src2.w
+
dst.z = src0.x + src1.x \times src2.x + src1.y \times src2.y
+
dst.w = src0.y + src1.x \times src2.z + src1.y \times src2.w
-Considered for removal.
+.. note::
+
+ Considered for removal.
From GL_NV_vertex_program2
^^^^^^^^^^^^^^^^^^^^^^^^^^
-ARA - Address Register Add
+.. opcode:: ARA - Address Register Add
TBD
- Considered for removal.
+.. note::
-ARR - Address Register Load With Round
+ Considered for removal.
+
+.. opcode:: ARR - Address Register Load With Round
.. math::
dst.w = round(src.w)
-BRA - Branch
+.. opcode:: BRA - Branch
pc = target
- Considered for removal.
+.. note::
+
+ Considered for removal.
-CAL - Subroutine Call
+.. opcode:: CAL - Subroutine Call
push(pc)
pc = target
-RET - Subroutine Call Return
+.. opcode:: RET - Subroutine Call Return
pc = pop()
Potential restrictions:
* Only occurs at end of function.
-SSG - Set Sign
+.. opcode:: SSG - Set Sign
.. math::
dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
-CMP - Compare
+.. opcode:: CMP - Compare
.. math::
dst.w = (src0.w < 0) ? src1.w : src2.w
-KIL - Conditional Discard
+.. opcode:: KIL - Conditional Discard
.. math::
endif
-SCS - Sine Cosine
+.. opcode:: SCS - Sine Cosine
.. math::
dst.y = 1
-TXB - Texture Lookup With Bias
+.. opcode:: TXB - Texture Lookup With Bias
TBD
-NRM - 3-component Vector Normalise
+.. opcode:: NRM - 3-component Vector Normalise
.. math::
dst.w = 1
-DIV - Divide
+.. opcode:: DIV - Divide
.. math::
dst.w = \frac{src0.w}{src1.w}
-DP2 - 2-component Dot Product
+.. opcode:: DP2 - 2-component Dot Product
-.. math::
+This instruction replicates its result.
- dst.x = src0.x \times src1.x + src0.y \times src1.y
-
- dst.y = src0.x \times src1.x + src0.y \times src1.y
-
- dst.z = src0.x \times src1.x + src0.y \times src1.y
+.. math::
- dst.w = src0.x \times src1.x + src0.y \times src1.y
+ dst = src0.x \times src1.x + src0.y \times src1.y
-TXL - Texture Lookup With LOD
+.. opcode:: TXL - Texture Lookup With LOD
TBD
-BRK - Break
+.. opcode:: BRK - Break
TBD
-IF - If
+.. opcode:: IF - If
TBD
-BGNFOR - Begin a For-Loop
+.. opcode:: BGNFOR - Begin a For-Loop
dst.x = floor(src.x)
dst.y = floor(src.y)
Note: The destination must be a loop register.
The source must be a constant register.
- Considered for cleanup / removal.
+.. note::
+
+ Considered for cleanup.
+
+.. note::
+
+ Considered for removal.
-REP - Repeat
+.. opcode:: REP - Repeat
TBD
-ELSE - Else
+.. opcode:: ELSE - Else
TBD
-ENDIF - End If
+.. opcode:: ENDIF - End If
TBD
-ENDFOR - End a For-Loop
+.. opcode:: ENDFOR - End a For-Loop
dst.x = dst.x + dst.z
dst.y = dst.y - 1.0
Note: The destination must be a loop register.
- Considered for cleanup / removal.
+.. note::
-ENDREP - End Repeat
+ Considered for cleanup.
+
+.. note::
+
+ Considered for removal.
+
+.. opcode:: ENDREP - End Repeat
TBD
-PUSHA - Push Address Register On Stack
+.. opcode:: PUSHA - Push Address Register On Stack
push(src.x)
push(src.y)
push(src.z)
push(src.w)
- Considered for cleanup / removal.
+.. note::
+
+ Considered for cleanup.
+
+.. note::
+
+ Considered for removal.
-POPA - Pop Address Register From Stack
+.. opcode:: POPA - Pop Address Register From Stack
dst.w = pop()
dst.z = pop()
dst.y = pop()
dst.x = pop()
- Considered for cleanup / removal.
+.. note::
+
+ Considered for cleanup.
+
+.. note::
+
+ Considered for removal.
From GL_NV_gpu_program4
Support for these opcodes indicated by a special pipe capability bit (TBD).
-CEIL - Ceiling
+.. opcode:: CEIL - Ceiling
.. math::
dst.w = \lceil src.w\rceil
-I2F - Integer To Float
+.. opcode:: I2F - Integer To Float
.. math::
dst.w = (float) src.w
-NOT - Bitwise Not
+.. opcode:: NOT - Bitwise Not
.. math::
dst.w = ~src.w
-TRUNC - Truncate
+.. opcode:: TRUNC - Truncate
.. math::
dst.w = trunc(src.w)
-SHL - Shift Left
+.. opcode:: SHL - Shift Left
.. math::
dst.w = src0.w << src1.x
-SHR - Shift Right
+.. opcode:: SHR - Shift Right
.. math::
dst.w = src0.w >> src1.x
-AND - Bitwise And
+.. opcode:: AND - Bitwise And
.. math::
dst.w = src0.w & src1.w
-OR - Bitwise Or
+.. opcode:: OR - Bitwise Or
.. math::
dst.w = src0.w | src1.w
-MOD - Modulus
+.. opcode:: MOD - Modulus
.. math::
dst.w = src0.w \bmod src1.w
-XOR - Bitwise Xor
+.. opcode:: XOR - Bitwise Xor
.. math::
- dst.x = src0.x ^ src1.x
+ dst.x = src0.x \oplus src1.x
- dst.y = src0.y ^ src1.y
+ dst.y = src0.y \oplus src1.y
- dst.z = src0.z ^ src1.z
+ dst.z = src0.z \oplus src1.z
- dst.w = src0.w ^ src1.w
+ dst.w = src0.w \oplus src1.w
-SAD - Sum Of Absolute Differences
+.. opcode:: SAD - Sum Of Absolute Differences
.. math::
dst.w = |src0.w - src1.w| + src2.w
-TXF - Texel Fetch
+.. opcode:: TXF - Texel Fetch
TBD
-TXQ - Texture Size Query
+.. opcode:: TXQ - Texture Size Query
TBD
-CONT - Continue
+.. opcode:: CONT - Continue
TBD
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-EMIT - Emit
+.. opcode:: EMIT - Emit
TBD
-ENDPRIM - End Primitive
+.. opcode:: ENDPRIM - End Primitive
TBD
^^^^^^^^^^
-BGNLOOP - Begin a Loop
+.. opcode:: BGNLOOP - Begin a Loop
TBD
-BGNSUB - Begin Subroutine
+.. opcode:: BGNSUB - Begin Subroutine
TBD
-ENDLOOP - End a Loop
+.. opcode:: ENDLOOP - End a Loop
TBD
-ENDSUB - End Subroutine
+.. opcode:: ENDSUB - End Subroutine
TBD
-NOP - No Operation
+.. opcode:: NOP - No Operation
Do nothing.
-NRM4 - 4-component Vector Normalise
-
-.. math::
-
- dst.x = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
+.. opcode:: NRM4 - 4-component Vector Normalise
- dst.y = \frac{src.y}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
+This instruction replicates its result.
- dst.z = \frac{src.z}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
+.. math::
- dst.w = \frac{src.w}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
+ dst = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
ps_2_x
^^^^^^^^^^^^
-CALLNZ - Subroutine Call If Not Zero
+.. opcode:: CALLNZ - Subroutine Call If Not Zero
TBD
-IFC - If
+.. opcode:: IFC - If
TBD
-BREAKC - Break Conditional
+.. opcode:: BREAKC - Break Conditional
TBD
+.. _doubleopcodes:
+
+Double Opcodes
+^^^^^^^^^^^^^^^
+
+.. opcode:: DADD - Add Double
+
+.. math::
+
+ dst.xy = src0.xy + src1.xy
+
+ dst.zw = src0.zw + src1.zw
+
+
+.. opcode:: DDIV - Divide Double
+
+.. math::
+
+ dst.xy = src0.xy / src1.xy
+
+ dst.zw = src0.zw / src1.zw
+
+.. opcode:: DSEQ - Set Double on Equal
+
+.. math::
+
+ dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
+
+ dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
+
+.. opcode:: DSLT - Set Double on Less than
+
+.. math::
+
+ dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
+
+ dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
+
+.. opcode:: DFRAC - Double Fraction
+
+.. math::
+
+ dst.xy = src.xy - \lfloor src.xy\rfloor
+
+ dst.zw = src.zw - \lfloor src.zw\rfloor
+
+
+.. opcode:: DFRACEXP - Convert Double Number to Fractional and Integral Components
+
+.. math::
+
+ dst0.xy = frexp(src.xy, dst1.xy)
+
+ dst0.zw = frexp(src.zw, dst1.zw)
+
+.. opcode:: DLDEXP - Multiple Double Number by Integral Power of 2
+
+.. math::
+
+ dst.xy = ldexp(src0.xy, src1.xy)
+
+ dst.zw = ldexp(src0.zw, src1.zw)
+
+.. opcode:: DMIN - Minimum Double
+
+.. math::
+
+ dst.xy = min(src0.xy, src1.xy)
+
+ dst.zw = min(src0.zw, src1.zw)
+
+.. opcode:: DMAX - Maximum Double
+
+.. math::
+
+ dst.xy = max(src0.xy, src1.xy)
+
+ dst.zw = max(src0.zw, src1.zw)
+
+.. opcode:: DMUL - Multiply Double
+
+.. math::
+
+ dst.xy = src0.xy \times src1.xy
+
+ dst.zw = src0.zw \times src1.zw
+
+
+.. opcode:: DMAD - Multiply And Add Doubles
+
+.. math::
+
+ dst.xy = src0.xy \times src1.xy + src2.xy
+
+ dst.zw = src0.zw \times src1.zw + src2.zw
+
+
+.. opcode:: DRCP - Reciprocal Double
+
+.. math::
+
+ dst.xy = \frac{1}{src.xy}
+
+ dst.zw = \frac{1}{src.zw}
+
+.. opcode:: DSQRT - Square root double
+
+.. math::
+
+ dst.xy = \sqrt{src.xy}
+
+ dst.zw = \sqrt{src.zw}
+
Explanation of symbols used
------------------------------
discard Discard fragment.
- dst First destination register.
+ pc Program counter.
- dst0 First destination register.
+ target Label of target instruction.
- pc Program counter.
- src First source register.
+Other tokens
+---------------
- src0 First source register.
- src1 Second source register.
+Declaration
+^^^^^^^^^^^
- src2 Third source register.
- target Label of target instruction.
+Declares a register that is will be referenced as an operand in Instruction
+tokens.
+File field contains register file that is being declared and is one
+of TGSI_FILE.
-Other tokens
----------------
+UsageMask field specifies which of the register components can be accessed
+and is one of TGSI_WRITEMASK.
+
+Interpolate field is only valid for fragment shader INPUT register files.
+It specifes the way input is being interpolated by the rasteriser and is one
+of TGSI_INTERPOLATE.
+
+If Dimension flag is set to 1, a Declaration Dimension token follows.
+
+If Semantic flag is set to 1, a Declaration Semantic token follows.
+
+CylindricalWrap bitfield is only valid for fragment shader INPUT register
+files. It specifies which register components should be subject to cylindrical
+wrapping when interpolating by the rasteriser. If TGSI_CYLINDRICAL_WRAP_X
+is set to 1, the X component should be interpolated according to cylindrical
+wrapping rules.
Declaration Semantic
for the perspective divide, if enabled.
As a vertex shader output, position should be scaled to the viewport. When
-used in fragment shaders, position will ---
-
-XXX --- wait a minute. Should position be in [0,1] for x and y?
+used in fragment shaders, position will be in window coordinates. The convention
+used depends on the FS_COORD_ORIGIN and FS_COORD_PIXEL_CENTER properties.
XXX additionally, is there a way to configure the perspective divide? it's
accelerated on most chipsets AFAIK...
""""""""""""""""""""""
XXX no clue
+
+
+Properties
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+
+ Properties are general directives that apply to the whole TGSI program.
+
+FS_COORD_ORIGIN
+"""""""""""""""
+
+Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
+The default value is UPPER_LEFT.
+
+If UPPER_LEFT, the position will be (0,0) at the upper left corner and
+increase downward and rightward.
+If LOWER_LEFT, the position will be (0,0) at the lower left corner and
+increase upward and rightward.
+
+OpenGL defaults to LOWER_LEFT, and is configurable with the
+GL_ARB_fragment_coord_conventions extension.
+
+DirectX 9/10 use UPPER_LEFT.
+
+FS_COORD_PIXEL_CENTER
+"""""""""""""""""""""
+
+Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
+The default value is HALF_INTEGER.
+
+If HALF_INTEGER, the fractionary part of the position will be 0.5
+If INTEGER, the fractionary part of the position will be 0.0
+
+Note that this does not affect the set of fragments generated by
+rasterization, which is instead controlled by gl_rasterization_rules in the
+rasterizer.
+
+OpenGL defaults to HALF_INTEGER, and is configurable with the
+GL_ARB_fragment_coord_conventions extension.
+
+DirectX 9 uses INTEGER.
+DirectX 10 uses HALF_INTEGER.
+
+
+
+Texture Sampling and Texture Formats
+------------------------------------
+
+This table shows how texture image components are returned as (x,y,z,w) tuples
+by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
+:opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
+well.
+
++--------------------+--------------+--------------------+--------------+
+| Texture Components | Gallium | OpenGL | Direct3D 9 |
++====================+==============+====================+==============+
+| R | XXX TBD | (r, 0, 0, 1) | (r, 1, 1, 1) |
++--------------------+--------------+--------------------+--------------+
+| RG | XXX TBD | (r, g, 0, 1) | (r, g, 1, 1) |
++--------------------+--------------+--------------------+--------------+
+| RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
++--------------------+--------------+--------------------+--------------+
+| RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
++--------------------+--------------+--------------------+--------------+
+| A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
++--------------------+--------------+--------------------+--------------+
+| L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
++--------------------+--------------+--------------------+--------------+
+| LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
++--------------------+--------------+--------------------+--------------+
+| I | (i, i, i, i) | (i, i, i, i) | N/A |
++--------------------+--------------+--------------------+--------------+
+| UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
+| | | [#envmap-bumpmap]_ | |
++--------------------+--------------+--------------------+--------------+
+| Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
+| | | [#depth-tex-mode]_ | |
++--------------------+--------------+--------------------+--------------+
+
+.. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
+.. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
+ or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.
projects / mesa.git / blobdiff