+.. _resourceopcodes:
+
+Resource Access Opcodes
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+Those opcodes follow very closely semantics of the respective Direct3D
+instructions. If in doubt double check Direct3D documentation.
+
+.. opcode:: LOAD - Simplified alternative to the "SAMPLE" instruction.
+ Using the provided integer address, LOAD fetches data
+ from the specified buffer/texture without any filtering.
+ The source data may come from any resource type other
+ than CUBE.
+ LOAD dst, address, resource
+ e.g.
+ LOAD TEMP[0], TEMP[1], RES[0]
+ The 'address' is specified as unsigned integers. If the
+ 'address' is out of range [0...(# texels - 1)] the
+ result of the fetch is always 0 in all components.
+ As such the instruction doesn't honor address wrap
+ modes, in cases where that behavior is desirable
+ 'sample' instruction should be used.
+ address.w always provides an unsigned integer mipmap
+ level. If the value is out of the range then the
+ instruction always returns 0 in all components.
+ address.yz are ignored for buffers and 1d textures.
+ address.z is ignored for 1d texture arrays and 2d
+ textures.
+ For 1D texture arrays address.y provides the array
+ index (also as unsigned integer). If the value is
+ out of the range of available array indices
+ [0... (array size - 1)] then the opcode always returns
+ 0 in all components.
+ For 2D texture arrays address.z provides the array
+ index, otherwise it exhibits the same behavior as in
+ the case for 1D texture arrays.
+ The exeact semantics of the source address are presented
+ in the table below:
+ resource type X Y Z W
+ ------------- ------------------------
+ PIPE_BUFFER x ignored
+ PIPE_TEXTURE_1D x mpl
+ PIPE_TEXTURE_2D x y mpl
+ PIPE_TEXTURE_3D x y z mpl
+ PIPE_TEXTURE_RECT x y mpl
+ PIPE_TEXTURE_CUBE not allowed as source
+ PIPE_TEXTURE_1D_ARRAY x idx mpl
+ PIPE_TEXTURE_2D_ARRAY x y idx mpl
+
+ Where 'mpl' is a mipmap level and 'idx' is the
+ array index.
+
+
+.. opcode:: LOAD_MS - Just like LOAD but allows fetch data from
+ multi-sampled surfaces.
+
+.. opcode:: SAMPLE - Using provided address, sample data from the
+ specified texture using the filtering mode identified
+ by the gven sampler. The source data may come from
+ any resource type other than buffers.
+ SAMPLE dst, address, resource, sampler
+ e.g.
+ SAMPLE TEMP[0], TEMP[1], RES[0], SAMP[0]
+
+.. opcode:: SAMPLE_B - Just like the SAMPLE instruction with the
+ exception that an additiona bias is applied to the
+ level of detail computed as part of the instruction
+ execution.
+ SAMPLE_B dst, address, resource, sampler, lod_bias
+ e.g.
+ SAMPLE_B TEMP[0], TEMP[1], RES[0], SAMP[0], TEMP[2].x
+
+.. opcode:: SAMPLE_C - Similar to the SAMPLE instruction but it
+ performs a comparison filter. The operands to SAMPLE_C
+ are identical to SAMPLE, except that tere is an additional
+ float32 operand, reference value, which must be a register
+ with single-component, or a scalar literal.
+ SAMPLE_C makes the hardware use the current samplers
+ compare_func (in pipe_sampler_state) to compare
+ reference value against the red component value for the
+ surce resource at each texel that the currently configured
+ texture filter covers based on the provided coordinates.
+ SAMPLE_C dst, address, resource.r, sampler, ref_value
+ e.g.
+ SAMPLE_C TEMP[0], TEMP[1], RES[0].r, SAMP[0], TEMP[2].x
+
+.. opcode:: SAMPLE_C_LZ - Same as SAMPLE_C, but LOD is 0 and derivatives
+ are ignored. The LZ stands for level-zero.
+ SAMPLE_C_LZ dst, address, resource.r, sampler, ref_value
+ e.g.
+ SAMPLE_C_LZ TEMP[0], TEMP[1], RES[0].r, SAMP[0], TEMP[2].x
+
+
+.. opcode:: SAMPLE_D - SAMPLE_D is identical to the SAMPLE opcode except
+ that the derivatives for the source address in the x
+ direction and the y direction are provided by extra
+ parameters.
+ SAMPLE_D dst, address, resource, sampler, der_x, der_y
+ e.g.
+ SAMPLE_D TEMP[0], TEMP[1], RES[0], SAMP[0], TEMP[2], TEMP[3]
+
+.. opcode:: SAMPLE_L - SAMPLE_L is identical to the SAMPLE opcode except
+ that the LOD is provided directly as a scalar value,
+ representing no anisotropy. Source addresses A channel
+ is used as the LOD.
+ SAMPLE_L dst, address, resource, sampler
+ e.g.
+ SAMPLE_L TEMP[0], TEMP[1], RES[0], SAMP[0]
+
+
+.. opcode:: GATHER4 - Gathers the four texels to be used in a bi-linear
+ filtering operation and packs them into a single register.
+ Only woth with 2D, 2D array, cubemaps, and cubemaps arrays.
+ For 2D textures, only the addressing modes of the sampler and
+ the top level of any mip pyramid are used. Set W to zero.
+ It behaves like the SAMPLE instruction, but a filtered
+ sample is not generated. The four samples that contribute
+ to filtering are places into xyzw in cunter-clockwise order,
+ starting with the (u,v) texture coordinate delta at the
+ following locations (-, +), (+, +), (+, -), (-, -), where
+ the magnitude of the deltas are half a texel.
+
+
+.. opcode:: RESINFO - query the dimensions of a given input buffer.
+ dst receives width, height, depth or array size and
+ number of mipmap levels. The dst can have a writemask
+ which will specify what info is the caller interested
+ in.
+ RESINFO dst, src_mip_level, resource
+ e.g.
+ RESINFO TEMP[0], TEMP[1].x, RES[0]
+ src_mip_level is an unsigned integer scalar. If it's
+ out of range then returns 0 for width, height and
+ depth/array size but the total number of mipmap is
+ still returned correctly for the given resource.
+ The returned width, height and depth values are for
+ the mipmap level selected by the src_mip_level and
+ are in the number of texels.
+ For 1d texture array width is in dst.x, array size
+ is in dst.y and dst.zw are always 0.
+
+.. opcode:: SAMPLE_POS - query the position of a given sample.
+ dst receives float4 (x, y, 0, 0) indicated where the
+ sample is located. If the resource is not a multi-sample
+ resource and not a render target, the result is 0.
+
+.. opcode:: SAMPLE_INFO - dst receives number of samples in x.
+ If the resource is not a multi-sample resource and
+ not a render target, the result is 0.
+
+
projects / mesa.git / blobdiff