X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/6b8a01fa803079631cf8841e8f06c7ad6a5c2695..bb9c978c66f4a1fa30ce276e880abe648c4b8881:/Issue.v

diff --git a/Issue.v b/Issue.v
index 4147c9f..3c8303a 100644
--- a/Issue.v
+++ b/Issue.v
@@ -130,18 +130,6 @@ module Issue(
 			def_cpsr = 1;
 			def_regs = 0;
 		end
-		`DECODE_ALU:	/* ALU */
-		begin
-			use_cpsr = `COND_MATTERS(cond) | (!insn[25] /* I */ && shift_requires_carry(insn[11:4]));
-			use_regs =
-				(insn[25] /* I */ ? 0 :
-					(insn[4] /* shift by reg */ ?
-						(idxbit(rs) | idxbit(rm)) :
-						(idxbit(rm)))) |
-				(((alu_opc != `ALU_MOV) && (alu_opc != `ALU_MVN)) ? idxbit(rn) : 0);
-			def_cpsr = insn[20] /* S */ | alu_is_logical(alu_opc);
-			def_regs = alu_flags_only(alu_opc) ? 0 : idxbit(rd);
-		end
 		`DECODE_ALU_SWP:	/* Atomic swap */
 		begin
 			use_cpsr = `COND_MATTERS(cond);
@@ -170,6 +158,18 @@ module Issue(
 			def_cpsr = 0;
 			def_regs = insn[20] /* L */ ? idxbit(rd) : 0;
 		end
+		`DECODE_ALU:	/* ALU */
+		begin
+			use_cpsr = `COND_MATTERS(cond) | (!insn[25] /* I */ && shift_requires_carry(insn[11:4]));
+			use_regs =
+				(insn[25] /* I */ ? 0 :
+					(insn[4] /* shift by reg */ ?
+						(idxbit(rs) | idxbit(rm)) :
+						(idxbit(rm)))) |
+				(((alu_opc != `ALU_MOV) && (alu_opc != `ALU_MVN)) ? idxbit(rn) : 0);
+			def_cpsr = insn[20] /* S */;
+			def_regs = alu_flags_only(alu_opc) ? 0 : idxbit(rd);
+		end
 		`DECODE_LDRSTR_UNDEFINED:	/* Undefined. I hate ARM */
 		begin	
 			use_cpsr = 0;
@@ -282,24 +282,25 @@ module Issue(
 		waiting_cpsr = use_cpsr & (cpsr_inflight[0] | cpsr_inflight[1]);
 		waiting_regs = |(use_regs & (regs_inflight[0] | regs_inflight[1]));
 		
-		outstall = waiting && !inbubble;	/* Happens in an always @*, because it is an exception. */
+		outstall = (waiting && !inbubble) || stall;	/* Happens in an always @*, because it is an exception. */
 	end
 	
 	/* Actually do the issue. */
 	always @(posedge clk)
 	begin
-		cpsr_inflight[0] <= cpsr_inflight[1];	/* I'm not sure how well selects work with arrays, and that seems like a dumb thing to get anusulated by. */
-		cpsr_inflight[1] <= (waiting || inbubble || !condition_met) ? 0 : def_cpsr;
-		regs_inflight[0] <= regs_inflight[1];
-		regs_inflight[1] <= (waiting || inbubble || !condition_met) ? 0 : def_regs;
-		
 		if (waiting)
-		begin
 			$display("ISSUE: Stalling instruction %08x because %d/%d", insn, waiting_cpsr, waiting_regs);
+	
+		if (!stall)
+		begin
+			cpsr_inflight[0] <= cpsr_inflight[1];	/* I'm not sure how well selects work with arrays, and that seems like a dumb thing to get anusulated by. */
+			cpsr_inflight[1] <= (waiting || inbubble || !condition_met) ? 0 : def_cpsr;
+			regs_inflight[0] <= regs_inflight[1];
+			regs_inflight[1] <= (waiting || inbubble || !condition_met) ? 0 : def_regs;
+			
+			outbubble <= inbubble | waiting | !condition_met;
+			outpc <= inpc;
+			outinsn <= insn;
 		end
-
-		outbubble <= inbubble | waiting | !condition_met;
-		outpc <= inpc;
-		outinsn <= insn;
 	end
 endmodule