r300/compiler: r500 hw support for break and continue in loops.

The BGNLOOP and ENDLOOP instructions are now being used correctly, which
makes break and continue possible.  The deadcode pass has been modified to
handle breaks, and the compiler is more careful about which loops are
unrolled.

1 files changed, 76 insertions, 38 deletions

diff --git a/src/mesa/drivers/dri/r300/compiler/r500_fragprog_emit.c b/src/mesa/drivers/dri/r300/compiler/r500_fragprog_emit.c
index 0bd8f0a239..c3f817ad4e 100644
--- a/src/mesa/drivers/dri/r300/compiler/r500_fragprog_emit.c
+++ b/src/mesa/drivers/dri/r300/compiler/r500_fragprog_emit.c
@@ -64,7 +64,12 @@ struct branch_info {
 };
 
 struct loop_info {
-	int LoopStart;
+	int BgnLoop;
+
+	int BranchDepth;
+	int * Brks;
+	int BrkCount;
+	int BrkReserved;
 };
 
 struct emit_state {
@@ -368,6 +373,12 @@ static void emit_flowcontrol(struct emit_state * s, struct rc_instruction * inst
 
 	unsigned int newip = ++s->Code->inst_end;
 
+	/* Currently all loops use the same integer constant to intialize
+	 * the loop variables. */
+	if(!s->Code->int_constants[0]) {
+		s->Code->int_constants[0] = R500_FC_INT_CONST_KR(0xff);
+		s->Code->int_constant_count = 1;
+	}
 	s->Code->inst[newip].inst0 = R500_INST_TYPE_FC | R500_INST_ALU_WAIT;
 
 	switch(inst->U.I.Opcode){
@@ -378,32 +389,69 @@ static void emit_flowcontrol(struct emit_state * s, struct rc_instruction * inst
 			s->Loops, s->CurrentLoopDepth, s->LoopsReserved, 1);
 
 		loop = &s->Loops[s->CurrentLoopDepth++];
-		
-		/* We don't emit an instruction for BGNLOOP, so we need to
-		 * decrement the instruction counter, but first we need to
-		 * set LoopStart to the current value of inst_end, which
-		 * will end up being the first real instruction in the loop.*/
-		loop->LoopStart = s->Code->inst_end--;
+		memset(loop, 0, sizeof(struct loop_info));
+		loop->BranchDepth = s->CurrentBranchDepth;
+		loop->BgnLoop = newip;
+
+		s->Code->inst[newip].inst2 = R500_FC_OP_LOOP
+			| R500_FC_JUMP_FUNC(0x00)
+			| R500_FC_IGNORE_UNCOVERED
+			;
 		break;
-	
 	case RC_OPCODE_BRK:
-		/* Don't emit an instruction for BRK */
-		s->Code->inst_end--;
+		loop = &s->Loops[s->CurrentLoopDepth - 1];
+		memory_pool_array_reserve(&s->C->Pool, int, loop->Brks,
+					loop->BrkCount, loop->BrkReserved, 1);
+
+		loop->Brks[loop->BrkCount++] = newip;
+		s->Code->inst[newip].inst2 = R500_FC_OP_BREAKLOOP
+			| R500_FC_JUMP_FUNC(0xff)
+			| R500_FC_B_OP1_DECR
+			| R500_FC_B_POP_CNT(
+				s->CurrentBranchDepth - loop->BranchDepth)
+			| R500_FC_IGNORE_UNCOVERED
+			;
 		break;
 
 	case RC_OPCODE_CONTINUE:
 		loop = &s->Loops[s->CurrentLoopDepth - 1];
-		s->Code->inst[newip].inst2 = R500_FC_OP_JUMP |
-			R500_FC_JUMP_FUNC(0xff);
-		s->Code->inst[newip].inst3 = R500_FC_JUMP_ADDR(loop->LoopStart);
+		s->Code->inst[newip].inst2 = R500_FC_OP_JUMP
+			| R500_FC_JUMP_FUNC(0xff)
+			| R500_FC_B_OP1_DECR
+			| R500_FC_B_POP_CNT(
+				s->CurrentBranchDepth -	loop->BranchDepth)
+			;
+		s->Code->inst[newip].inst3 = R500_FC_JUMP_ADDR(loop->BgnLoop);
 		break;
 
 	case RC_OPCODE_ENDLOOP:
-		/* Don't emit an instruction for ENDLOOP */
-		s->Code->inst_end--;
+	{
+		unsigned int i;
+		loop = &s->Loops[s->CurrentLoopDepth - 1];
+		/* Emit ENDLOOP */
+		s->Code->inst[newip].inst2 = R500_FC_OP_ENDLOOP
+			| R500_FC_JUMP_FUNC(0xff)
+			| R500_FC_JUMP_ANY
+			| R500_FC_IGNORE_UNCOVERED
+			;
+		/* The constant integer at index 0 is used by all loops. */
+		s->Code->inst[newip].inst3 = R500_FC_INT_ADDR(0)
+			| R500_FC_JUMP_ADDR(loop->BgnLoop + 1)
+			;
+
+		/* Set jump address and int constant for BGNLOOP */
+		s->Code->inst[loop->BgnLoop].inst3 = R500_FC_INT_ADDR(0)
+			| R500_FC_JUMP_ADDR(newip)
+			;
+
+		/* Set jump address for the BRK instructions. */
+		while(loop->BrkCount--) {
+			s->Code->inst[loop->Brks[loop->BrkCount]].inst3 =
+						R500_FC_JUMP_ADDR(newip + 1);
+		}
 		s->CurrentLoopDepth--;
 		break;
-
+	}
 	case RC_OPCODE_IF:
 		if ( s->CurrentBranchDepth >= MAX_BRANCH_DEPTH_FULL) {
 			rc_error(s->C, "Branch depth exceeds hardware limit");
@@ -442,24 +490,16 @@ static void emit_flowcontrol(struct emit_state * s, struct rc_instruction * inst
 		}
 
 		branch = &s->Branches[s->CurrentBranchDepth - 1];
-		
-		if(inst->Prev->U.I.Opcode == RC_OPCODE_BRK){
-			branch->Endif = --s->Code->inst_end;
-			s->Code->inst[branch->Endif].inst2 |=
-				R500_FC_B_OP0_DECR;
-		}
-		else{
-			branch->Endif = newip;
-		
-			s->Code->inst[branch->Endif].inst2 = R500_FC_OP_JUMP
-				| R500_FC_A_OP_NONE /* no address stack */
-				| R500_FC_JUMP_ANY /* docs says set this, but I don't understand why */
-				| R500_FC_B_OP0_DECR /* decrement branch counter if stay */
-				| R500_FC_B_OP1_NONE /* no branch counter if stay */
-				| R500_FC_B_POP_CNT(1)
+		branch->Endif = newip;
+
+		s->Code->inst[branch->Endif].inst2 = R500_FC_OP_JUMP
+			| R500_FC_A_OP_NONE /* no address stack */
+			| R500_FC_JUMP_ANY /* docs says set this, but I don't understand why */
+			| R500_FC_B_OP0_DECR /* decrement branch counter if stay */
+			| R500_FC_B_OP1_NONE /* no branch counter if stay */
+			| R500_FC_B_POP_CNT(1)
 			;
-			s->Code->inst[branch->Endif].inst3 = R500_FC_JUMP_ADDR(branch->Endif + 1);
-		}
+		s->Code->inst[branch->Endif].inst3 = R500_FC_JUMP_ADDR(branch->Endif + 1);
 		s->Code->inst[branch->If].inst2 = R500_FC_OP_JUMP
 			| R500_FC_A_OP_NONE /* no address stack */
 			| R500_FC_JUMP_FUNC(0x0f) /* jump if ALU result is false */
@@ -544,11 +584,9 @@ void r500BuildFragmentProgramHwCode(struct r300_fragment_program_compiler *compi
 		code->inst[ip].inst0 = R500_INST_TYPE_OUT | R500_INST_TEX_SEM_WAIT;
 	}
 
-	/* Use FULL flow control mode if branches are nested deep enough.
-	 * We don not need to enable FULL flow control mode for loops, becasue
-	 * we aren't using the hardware loop instructions.
-	 */
-	if (s.MaxBranchDepth >= 4) {
+	/* Enable full flow control mode if we are using loops or have if
+	 * statements nested at least four deep. */
+	if (s.MaxBranchDepth >= 4 || s.LoopsReserved > 0) {
 		if (code->max_temp_idx < 1)
 			code->max_temp_idx = 1;