Implement single-stepping

2 files changed, 8 insertions, 4 deletions

diff --git a/rtl/core/fetch/fetch.sv b/rtl/core/fetch/fetch.sv
index acc8e9d..c024e7d 100644
--- a/rtl/core/fetch/fetch.sv
+++ b/rtl/core/fetch/fetch.sv
@@ -11,18 +11,20 @@ module core_fetch
 	             wr_pc,
 	             prefetch_flush,
 	input  ptr   branch_target,
+	             porch_insn_pc,
 	input  word  wr_current,
 	             fetch_data,
 
 	output logic fetch,
 	             flush,
+	             nop,
 	output word  insn,
 	output ptr   insn_pc,
 	             addr,
 	             fetch_head
 );
 
-	ptr next_pc, hold_addr, target;
+	ptr hold_addr, target;
 	logic branch, prefetch_ready, fetched_valid, discard, pending, next_pending;
 
 	assign fetch = prefetch_ready && !discard;
@@ -44,7 +46,7 @@ module core_fetch
 		if(branch)
 			fetch_head = target;
 		else if(prefetch_flush)
-			fetch_head = next_pc;
+			fetch_head = porch_insn_pc;
 		else
 			fetch_head = {30{1'bx}};
 
diff --git a/rtl/core/fetch/prefetch.sv b/rtl/core/fetch/prefetch.sv
index 2f0a866..1b5a4c5 100644
--- a/rtl/core/fetch/prefetch.sv
+++ b/rtl/core/fetch/prefetch.sv
@@ -13,15 +13,17 @@ module core_prefetch
 
 	output word  insn,
 	output ptr   insn_pc,
-	             next_pc,
-	output logic fetch
+	output logic fetch,
+	             nop
 );
 
 	localparam SIZE = (1 << ORDER) - 1;
 
+	ptr next_pc;
 	logic[31:0] prefetch[SIZE];
 	logic[ORDER - 1:0] valid;
 
+	assign nop = flush ? 1 : ~|valid;
 	assign insn = flush ? `NOP : prefetch[0];
 	assign next_pc = ~stall & |valid ? insn_pc + 1 : insn_pc;
 	assign fetch = !stall || ~&valid;