Kenneth Graunke
10ff6772c8
Consider the following code sequence: mul(8) g4<1>F g1<0,4,1>.wzwwF g3<4,4,1>.wzwwF mov.sat(8) m1<1>.xyF g4<4,4,1>F mul(8) g4<1>F g1<0,4,1>.xxyxF g3<4,4,1>.xxyxF mov.sat(8) m1<1>.zwF g4<4,4,1>F The compute-to-MRF pass will discover the first mov.sat and attempt to replace it by rewriting earlier instructions. Everything works out, so it replaces scan_inst's destination file, reg, and reg_offset, resulting in: mul(8) m1<1>F g1<0,4,1>.wzwwF g3<4,4,1>.wzwwF mul(8) g4<1>F g1<0,4,1>.xxyxF g3<4,4,1>.xxyxF mov.sat(8) m1<1>.zwF g4<4,4,1>F Unfortunately, it loses the .xy writemask on the mov.sat's MRF destination. While this doesn't pose an immediate problem, it then proceeds to transform the second mov.sat, resulting in: mul(8) m1<1>F g1<0,4,1>.wzwwF g3<4,4,1>.wzwwF mul(8) m1<1>F g1<0,4,1>.xxyxF g3<4,4,1>.xxyxF Instead of writing both halves of the vector (like the original code), it overwrites the full vector both times, clobbering the desired .xy values. When encountering a MOV, the compute-to-MRF code scans for instructions which generate channels of the MOV source. It ensures that all necessary channels are available (possibly written by several instructions). In this case, *more* channels are available than necessary, so we want to take the subset that's actually used. Taking the bitwise and of both writemasks should accomplish that. This was discovered by analyzing an ARB_vertex_program test (glean/vertProg1/MUL test (with swizzle and masking)) with my new Mesa IR -> Vec4 IR translator code. However, it should be possible with GLSL programs as well. NOTE: This is a candidate for stable release branches. Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Eric Anholt <eric@anholt.net>
File: docs/README.WIN32 Last updated: 23 April 2011 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons osmesa mesagdi to build classic mesa Windows GDI drivers; or scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.