gallium: Add SWITCH, CASE, DEFAULT and ENDSWITCH opcodes to TGSI.

Provide reference implementation of them in tgsi_exec.

Note that BREAK opcode is overloaded and can be used to break out
of either a loop or a switch-case statement.

1 files changed, 34 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.h b/src/gallium/auxiliary/tgsi/tgsi_exec.h
index afaf5c39c4..aa3a98d7f1 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.h
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.h
@@ -179,6 +179,7 @@ struct tgsi_exec_labels
 
 #define TGSI_EXEC_MAX_COND_NESTING  32
 #define TGSI_EXEC_MAX_LOOP_NESTING  32
+#define TGSI_EXEC_MAX_SWITCH_NESTING 32
 #define TGSI_EXEC_MAX_CALL_NESTING  32
 
 /* The maximum number of input attributes per vertex. For 2D
@@ -206,9 +207,29 @@ struct tgsi_call_record
    uint CondStackTop;
    uint LoopStackTop;
    uint ContStackTop;
+   int SwitchStackTop;
+   int BreakStackTop;
    uint ReturnAddr;
 };
 
+
+/* Switch-case block state. */
+struct tgsi_switch_record {
+   uint mask;                          /**< execution mask */
+   union tgsi_exec_channel selector;   /**< a value case statements are compared to */
+   uint defaultMask;                   /**< non-execute mask for default case */
+};
+
+
+enum tgsi_break_type {
+   TGSI_EXEC_BREAK_INSIDE_LOOP,
+   TGSI_EXEC_BREAK_INSIDE_SWITCH
+};
+
+
+#define TGSI_EXEC_MAX_BREAK_STACK (TGSI_EXEC_MAX_LOOP_NESTING + TGSI_EXEC_MAX_SWITCH_NESTING)
+
+
 /**
  * Run-time virtual machine state for executing TGSI shader.
  */
@@ -251,6 +272,12 @@ struct tgsi_exec_machine
    uint FuncMask;  /**< For function calls */
    uint ExecMask;  /**< = CondMask & LoopMask */
 
+   /* Current switch-case state. */
+   struct tgsi_switch_record Switch;
+
+   /* Current break type. */
+   enum tgsi_break_type BreakType;
+
    /** Condition mask stack (for nested conditionals) */
    uint CondStack[TGSI_EXEC_MAX_COND_NESTING];
    int CondStackTop;
@@ -271,6 +298,13 @@ struct tgsi_exec_machine
    uint ContStack[TGSI_EXEC_MAX_LOOP_NESTING];
    int ContStackTop;
 
+   /** Switch case stack */
+   struct tgsi_switch_record SwitchStack[TGSI_EXEC_MAX_SWITCH_NESTING];
+   int SwitchStackTop;
+
+   enum tgsi_break_type BreakStack[TGSI_EXEC_MAX_BREAK_STACK];
+   int BreakStackTop;
+
    /** Function execution mask stack (for executing subroutine code) */
    uint FuncStack[TGSI_EXEC_MAX_CALL_NESTING];
    int FuncStackTop;