added branch support, maybe

[firearm.git] / Issue.v

diff --git a/Issue.v b/Issue.v
index 8fba3088d04d4521a9fe099d336ce84b93d0df5d..ef53bc3ed932365292c5969a7a95b7f74d88f42f 100644 (file)
--- a/Issue.v
+++ b/Issue.v
@@ -167,7 +167,7 @@ module Issue(
                                                (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_cpsr = insn[20] /* S */;
                        def_regs = alu_flags_only(alu_opc) ? 0 : idxbit(rd);
                end
                `DECODE_LDRSTR_UNDEFINED:       /* Undefined. I hate ARM */
@@ -282,24 +282,32 @@ 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);
-               end
 
-               outbubble <= inbubble | waiting | !condition_met;
-               outpc <= inpc;
-               outinsn <= insn;
+               if(flush)
+               begin
+                       cpsr_inflight[0] = 1'b0;
+                       cpsr_inflight[1] = 1'b0;
+                       regs_inflight[0] = 16'b0;
+                       regs_inflight[1] = 16'b0;
+               end
+               else 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 | flush;
+                       outpc <= inpc;
+                       outinsn <= insn;
+               end
        end
 endmodule