decrease max path lengthHEADmaster

+ Not fully functional, but good enough for now

1 files changed, 22 insertions, 40 deletions

diff --git a/src/ttarv32.sv b/src/ttarv32.sv
index 0edf1cb..cb04824 100644
--- a/src/ttarv32.sv
+++ b/src/ttarv32.sv
@@ -1,8 +1,9 @@
 `include "common.svh"
 
+`default_nettype none
+
 module ttarv32 #(
 	parameter SLOT_COUNT,
-	parameter SLOT_DEPTH,
 	parameter ALU_COUNT
 )(
 	input clk_i,
@@ -13,7 +14,7 @@ module ttarv32 #(
 
 typedef struct packed {
 	mov_t[1:0] in;
-	mov_t[SLOT_DEPTH-1:0] out;
+	mov_t out;
 	op_t op;
 	imm_t imm;
 } slot_t;
@@ -39,63 +40,44 @@ rv2insn #(
 	.que_o(rv_que)
 );
 
-typedef struct packed {
-	insn_t[SLOT_COUNT-1:0] que;
-	xlen_t pc;
-} merge_t;
-
-/* repetition from sched.sv, hmm */
-function automatic insn_t[SLOT_COUNT-1:0] next_insn(insn_t[SLOT_COUNT-1:0] que);
-	return que >> $bits(insn_t);
-endfunction
-
-function automatic logic is_noop(mov_t m);
-	return m.src == NOP && m.dst == NOP;
-endfunction
-
-/* not the best thing in the world but good enough for now */
-function automatic logic is_free(insn_t i);
-	return is_noop(i.in[0]) & is_noop(i.in[1]) & is_noop(i.out);
+function automatic insn_t[SLOT_COUNT-1:0] merge(insn_t[SLOT_COUNT-1:0] prev_que, insn_t[SLOT_COUNT-1:0] decoded, bit[$clog2(SLOT_COUNT)-1:0] shift);
+	return prev_que | (decoded << (shift * $bits(insn_t)));
 endfunction
 
-function automatic merge_t merge(int i,
-	insn_t[SLOT_COUNT-1:0] prev_que, insn_t[SLOT_COUNT-1:0] next_que, xlen_t pc);
-	if (i < SLOT_COUNT) begin
-		logic ok = is_free(prev_que[i]);
-		prev_que[i] = ok ? next_que[0] : prev_que[i];
-		return merge(i + 1,
-			prev_que,
-			ok ? next_insn(next_que) : next_que,
-			ok ? pc + 1 : pc);
-	end else begin
-		return {prev_que, pc};
-	end
-endfunction
+bit[$clog2(SLOT_COUNT)-1:0] shift_r, shift;
 
-merge_t merged;
-assign merged = merge(0, prev_que_r, rv_que, pc_r);
+insn_t[SLOT_COUNT-1:0] merged_que;
+assign merged_que = merge(prev_que_r, rv_que, shift_r);
 
 sched #(
 	.QUE_DEPTH(SLOT_COUNT),
 	.SLOT_COUNT(SLOT_COUNT),
-	.SLOT_DEPTH(SLOT_DEPTH),
 	.slot_t(slot_t)
 ) sched (
-	.que_i(merged.que),
+	.clk_i(clk_i),
+	.rst_ni(rst_ni),
+	.que_i(merged_que),
 	.que_o(next_que),
 	.slots_i(prev_slots_r),
-	.slots_o(next_slots)
+	.slots_o(next_slots),
+	.shift_o(shift)
 );
 
 always_ff @(posedge clk_i or negedge rst_ni) begin
 	if (!rst_ni) begin
 		prev_slots_r <= 0;
-		prev_que_r <= 0;
+		prev_que_r   <= 0;
+		shift_r      <= 0;
+
 		pc_r <= 0;
+		pc_o <= 0;
 	end else begin
 		prev_slots_r <= next_slots;
-		prev_que_r <= next_que;
-		pc_r <= merged.pc;
+		prev_que_r   <= next_que;
+		shift_r      <= shift;
+
+		pc_o <= pc_r + xlen_t'(shift);
+		pc_r <= pc_o;
 	end
 end