From 794579105a7c4868403f371e7a7deaf022373082 Mon Sep 17 00:00:00 2001 From: Roland Scheidegger Date: Sat, 20 Apr 2013 00:34:20 +0200 Subject: [PATCH] gallium: document breakc and switch/case/default/endswitch docs were missing, especially the opcode-from-hell switch however is anything but obvious. Reviewed-by: Jose Fonseca --- 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 b7180f85df4..03bbd6fd23a 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. .. 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 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 evaluated at bit level against the SWITCH src 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 -- 2.30.2