From: Francisco Jerez Date: Wed, 22 Apr 2015 13:44:18 +0000 (+0300) Subject: i965/fs: Import image memory offset calculation code. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1a37619763a99b78aa574aca0058eda86de7a0dc;p=mesa.git i965/fs: Import image memory offset calculation code. Define a function to calculate the memory address of the image location given by a vector of coordinates. This is required in cases where we need to fall back to untyped surface access, which take a raw memory offset and know nothing about surface coordinates, type conversion or memory tiling and swizzling. They are still useful because typed surface reads don't support any 64 or 128-bit formats on IVB, and they don't support any 128-bit formats on HSW and BDW. The tiling algorithm is implemented based on a number of parameters which are passed in as uniforms and determine whether the surface layout is X-tiled, Y-tiled or untiled. This allows binding surfaces of different tiling layouts to the pipeline without recompiling the program. v2: Drop VEC4 suport. v3: Rebase. v4: Add plenty of comments (Jason). Reviewed-by: Jason Ekstrand --- diff --git a/src/mesa/drivers/dri/i965/brw_fs_surface_builder.cpp b/src/mesa/drivers/dri/i965/brw_fs_surface_builder.cpp index 5ee04dece88..a0bedf26bc9 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_surface_builder.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_surface_builder.cpp @@ -215,4 +215,173 @@ namespace { return BRW_PREDICATE_NORMAL; } } + + namespace image_coordinates { + /** + * Calculate the offset in memory of the texel given by \p coord. + * + * This is meant to be used with untyped surface messages to access a + * tiled surface, what involves taking into account the tiling and + * swizzling modes of the surface manually so it will hopefully not + * happen very often. + * + * The tiling algorithm implemented here matches either the X or Y + * tiling layouts supported by the hardware depending on the tiling + * coefficients passed to the program as uniforms. See Volume 1 Part 2 + * Section 4.5 "Address Tiling Function" of the IVB PRM for an in-depth + * explanation of the hardware tiling format. + */ + fs_reg + emit_address_calculation(const fs_builder &bld, const fs_reg &image, + const fs_reg &coord, unsigned dims) + { + const brw_device_info *devinfo = bld.shader->devinfo; + const fs_reg off = offset(image, bld, BRW_IMAGE_PARAM_OFFSET_OFFSET); + const fs_reg stride = offset(image, bld, BRW_IMAGE_PARAM_STRIDE_OFFSET); + const fs_reg tile = offset(image, bld, BRW_IMAGE_PARAM_TILING_OFFSET); + const fs_reg swz = offset(image, bld, BRW_IMAGE_PARAM_SWIZZLING_OFFSET); + const fs_reg addr = bld.vgrf(BRW_REGISTER_TYPE_UD, 2); + const fs_reg tmp = bld.vgrf(BRW_REGISTER_TYPE_UD, 2); + const fs_reg minor = bld.vgrf(BRW_REGISTER_TYPE_UD, 2); + const fs_reg major = bld.vgrf(BRW_REGISTER_TYPE_UD, 2); + const fs_reg dst = bld.vgrf(BRW_REGISTER_TYPE_UD); + + /* Shift the coordinates by the fixed surface offset. It may be + * non-zero if the image is a single slice of a higher-dimensional + * surface, or if a non-zero mipmap level of the surface is bound to + * the pipeline. The offset needs to be applied here rather than at + * surface state set-up time because the desired slice-level may + * start mid-tile, so simply shifting the surface base address + * wouldn't give a well-formed tiled surface in the general case. + */ + for (unsigned c = 0; c < 2; ++c) + bld.ADD(offset(addr, bld, c), offset(off, bld, c), + (c < dims ? + offset(retype(coord, BRW_REGISTER_TYPE_UD), bld, c) : + fs_reg(0))); + + /* The layout of 3-D textures in memory is sort-of like a tiling + * format. At each miplevel, the slices are arranged in rows of + * 2^level slices per row. The slice row is stored in tmp.y and + * the slice within the row is stored in tmp.x. + * + * The layout of 2-D array textures and cubemaps is much simpler: + * Depending on whether the ARYSPC_LOD0 layout is in use it will be + * stored in memory as an array of slices, each one being a 2-D + * arrangement of miplevels, or as a 2D arrangement of miplevels, + * each one being an array of slices. In either case the separation + * between slices of the same LOD is equal to the qpitch value + * provided as stride.w. + * + * This code can be made to handle either 2D arrays and 3D textures + * by passing in the miplevel as tile.z for 3-D textures and 0 in + * tile.z for 2-D array textures. + * + * See Volume 1 Part 1 of the Gen7 PRM, sections 6.18.4.7 "Surface + * Arrays" and 6.18.6 "3D Surfaces" for a more extensive discussion + * of the hardware 3D texture and 2D array layouts. + */ + if (dims > 2) { + /* Decompose z into a major (tmp.y) and a minor (tmp.x) + * index. + */ + bld.BFE(offset(tmp, bld, 0), offset(tile, bld, 2), fs_reg(0), + offset(retype(coord, BRW_REGISTER_TYPE_UD), bld, 2)); + bld.SHR(offset(tmp, bld, 1), + offset(retype(coord, BRW_REGISTER_TYPE_UD), bld, 2), + offset(tile, bld, 2)); + + /* Take into account the horizontal (tmp.x) and vertical (tmp.y) + * slice offset. + */ + for (unsigned c = 0; c < 2; ++c) { + bld.MUL(offset(tmp, bld, c), + offset(stride, bld, 2 + c), offset(tmp, bld, c)); + bld.ADD(offset(addr, bld, c), + offset(addr, bld, c), offset(tmp, bld, c)); + } + } + + if (dims > 1) { + /* Calculate the major/minor x and y indices. In order to + * accommodate both X and Y tiling, the Y-major tiling format is + * treated as being a bunch of narrow X-tiles placed next to each + * other. This means that the tile width for Y-tiling is actually + * the width of one sub-column of the Y-major tile where each 4K + * tile has 8 512B sub-columns. + * + * The major Y value is the row of tiles in which the pixel lives. + * The major X value is the tile sub-column in which the pixel + * lives; for X tiling, this is the same as the tile column, for Y + * tiling, each tile has 8 sub-columns. The minor X and Y indices + * are the position within the sub-column. + */ + for (unsigned c = 0; c < 2; ++c) { + /* Calculate the minor x and y indices. */ + bld.BFE(offset(minor, bld, c), offset(tile, bld, c), + fs_reg(0), offset(addr, bld, c)); + + /* Calculate the major x and y indices. */ + bld.SHR(offset(major, bld, c), + offset(addr, bld, c), offset(tile, bld, c)); + } + + /* Calculate the texel index from the start of the tile row and + * the vertical coordinate of the row. + * Equivalent to: + * tmp.x = (major.x << tile.y << tile.x) + + * (minor.y << tile.x) + minor.x + * tmp.y = major.y << tile.y + */ + bld.SHL(tmp, major, offset(tile, bld, 1)); + bld.ADD(tmp, tmp, offset(minor, bld, 1)); + bld.SHL(tmp, tmp, offset(tile, bld, 0)); + bld.ADD(tmp, tmp, minor); + bld.SHL(offset(tmp, bld, 1), + offset(major, bld, 1), offset(tile, bld, 1)); + + /* Add it to the start of the tile row. */ + bld.MUL(offset(tmp, bld, 1), + offset(tmp, bld, 1), offset(stride, bld, 1)); + bld.ADD(tmp, tmp, offset(tmp, bld, 1)); + + /* Multiply by the Bpp value. */ + bld.MUL(dst, tmp, stride); + + if (devinfo->gen < 8 && !devinfo->is_baytrail) { + /* Take into account the two dynamically specified shifts. + * Both need are used to implement swizzling of X-tiled + * surfaces. For Y-tiled surfaces only one bit needs to be + * XOR-ed with bit 6 of the memory address, so a swz value of + * 0xff (actually interpreted as 31 by the hardware) will be + * provided to cause the relevant bit of tmp.y to be zero and + * turn the first XOR into the identity. For linear surfaces + * or platforms lacking address swizzling both shifts will be + * 0xff causing the relevant bits of both tmp.x and .y to be + * zero, what effectively disables swizzling. + */ + for (unsigned c = 0; c < 2; ++c) + bld.SHR(offset(tmp, bld, c), dst, offset(swz, bld, c)); + + /* XOR tmp.x and tmp.y with bit 6 of the memory address. */ + bld.XOR(tmp, tmp, offset(tmp, bld, 1)); + bld.AND(tmp, tmp, fs_reg(1 << 6)); + bld.XOR(dst, dst, tmp); + } + + } else { + /* Multiply by the Bpp/stride value. Note that the addr.y may be + * non-zero even if the image is one-dimensional because a + * vertical offset may have been applied above to select a + * non-zero slice or level of a higher-dimensional texture. + */ + bld.MUL(offset(addr, bld, 1), + offset(addr, bld, 1), offset(stride, bld, 1)); + bld.ADD(addr, addr, offset(addr, bld, 1)); + bld.MUL(dst, addr, stride); + } + + return dst; + } + } }