Modifiers are actually very useful with MOV. However I don't think the modifiers really care what the type is. They just change the sign bit of float (which is a bitwise operation). Also, UCMP doesn't do anything with the 2nd and 3rd argument, so their types don't matter.
I think the ABS and SUB opcodes should be removed in favor of the modifiers. Marek On Wed, May 8, 2013 at 12:14 PM, Christoph Bumiller <e0425...@student.tuwien.ac.at> wrote: > On 08.05.2013 03:48, srol...@vmware.com wrote: >> From: Roland Scheidegger <srol...@vmware.com> >> >> UCMP while an integer opcode isn't really consistently implemented as >> having all integer arguments. softpipe will assume all arguments are >> ints, whereas gallivm has the arguments defined as untyped which >> means they'll get treated as floats. This means input modifiers will >> not work the same. Fix this by saying only first arg is an integer, >> which seems more useful than making all arguments integers - this would >> be similar to d3d10 movc opcode. >> --- >> src/gallium/docs/source/tgsi.rst | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/src/gallium/docs/source/tgsi.rst >> b/src/gallium/docs/source/tgsi.rst >> index 3af1fb7..852f8a0 100644 >> --- a/src/gallium/docs/source/tgsi.rst >> +++ b/src/gallium/docs/source/tgsi.rst >> @@ -1291,6 +1291,11 @@ Support for these opcodes indicated by >> PIPE_SHADER_CAP_INTEGERS (all of them?) >> >> .. opcode:: UCMP - Integer Conditional Move >> >> +.. note:: >> + >> + Only the first source arg is an integer, the 2nd and 3rd ones are >> + considered floats (for input modifier purposes). >> + > > As long as you patch up all the occurrences of > tgsi_opcode_infer_src_type and make it take an argument to identify the > source ... > > I'd rather just forbid modifiers on moves, i.e. MOV and UCMP, since at > least MOV returns TGSI_TYPE_UNTYPED and untyped values can't be operated on. > For the ordinary MOV we have NEG and ABS, and for UCMP the backend > optimizer can take care of merging modifiers into the instruction > (nvc0's UCMP (slct u32) doesn't support modifiers). > >> .. math:: >> >> dst.x = src0.x ? src1.x : src2.x >> > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
