----- Original Message ----- > From: Roland Scheidegger <srol...@vmware.com> > > docs were missing, especially the opcode-from-hell switch however is anything > but obvious. > --- > src/gallium/docs/source/tgsi.rst | 57 > ++++++++++++++++++++++++++++++++++---- > 1 file changed, 51 insertions(+), 6 deletions(-) > > diff --git a/src/gallium/docs/source/tgsi.rst > b/src/gallium/docs/source/tgsi.rst > index b7180f8..b46347e 100644 > --- a/src/gallium/docs/source/tgsi.rst > +++ b/src/gallium/docs/source/tgsi.rst > @@ -861,7 +861,18 @@ This instruction replicates its result. > > .. opcode:: BRK - Break > > - TBD > + Unconditionally moves the point of execution to the instruction after the > + next endloop or endswitch. The instruction must appear within a > loop/endloop > + or switch/endswitch. > + > + > +.. opcode:: BREAKC - Break Conditional > + > + Conditionally moves the point of execution to the instruction after the > + next endloop or endswitch. The instruction must appear within a > loop/endloop > + or switch/endswitch. > + Condition evaluates to true if src0.x != 0 where src0.x is interpreted > + as an integer register.
This is fine. But I do wonder if hardware can really benefit from "UIF foo; BREAK; ENDIF" vs "BREAKC foo", or if this is just syntactic sugar that merely burdens developers. BTW, svga translates BREAKC, though I think it doesn't follow anywhere near these semantics, so that translation should be removed from the driver: $ git grep BREAKC [...] src/gallium/drivers/svga/svga_tgsi_insn.c: case TGSI_OPCODE_BREAKC: return SVGA3DOP_BREAKC; [...] > > .. opcode:: IF - Float If > @@ -892,6 +903,45 @@ This instruction replicates its result. > Ends an IF or UIF block. > > > +.. opcode:: SWITCH - Switch > + > + Starts a c-style switch expression. The switch consists of one or C-style > multiple > + CASE statements, and at most one DEFAULT statement. Execution of a > statement > + ends when a BRK is hit, but just like in C falling through to other cases > + without a break is allowed. Similarly, DEFAULT label is allowed anywhere > not > + just as last statement, and fallthrough is allowed into/from it. > + CASE src arguments are evaulated at bit level against the SWITCH src evaluated > argument. > + > + Example: > + SWITCH src[0].x > + CASE src[0].x > + (some instructions here) > + (optional BRK here) > + DEFAULT > + (some instructions here) > + (optional BRK here) > + CASE src[0].x > + (some instructions here) > + (optional BRK here) > + ENDSWITCH > + > + > +.. opcode:: CASE - Switch case > + > + This represents a switch case label. The src arg must be an integer > immediate. > + > + > +.. opcode:: DEFAULT - Switch default > + > + This represents the default case in the switch, which is taken if no > other > + case matches. > + > + > +.. opcode:: ENDSWITCH - End of switch > + > + Ends a switch expression. > + > + > .. opcode:: PUSHA - Push Address Register On Stack > > push(src.x) > @@ -1210,11 +1260,6 @@ XXX wait what > > TBD > > - > -.. opcode:: BREAKC - Break Conditional > - > - TBD > - > .. _doubleopcodes: > > Double ISA > -- > 1.7.9.5 > Reviewed-by: Jose Fonseca <jfons...@vmware.com> _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
