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Connected flush signal, emptying scoreboard

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This commit is contained in:
Florian Zaruba 2017-04-08 23:45:28 +02:00
parent 3d334e58a7
commit 9866b4adab
1 changed files with 11 additions and 6 deletions
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17
scoreboard.sv
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@ -28,7 +28,7 @@ module scoreboard #(
// instruction to put on top of scoreboard e.g.: top pointer
// we can always put this instruction to the top unless we signal with asserted full_o
input dtype decoded_instr_i,
input logic decoded_intr_valid_i,
input logic decoded_instr_valid_i,
// instruction to issue logic, if issue_instr_valid and issue_ready is asserted, advance the issue pointer
output dtype issue_instr_o,
@ -53,8 +53,8 @@ logic empty;
// full and empty signaling: signal that we are not able to take new instructions
// track pointer overflow
assign pointer_overflow = (commit_pointer_q <= top_pointer_q) ? 1'b0 : 1'b1;
assign full_o = (pointer_overflow) ? commit_pointer_q == top_pointer_q : 1'b0;
assign empty = (pointer_overflow) ? 1'b0 : commit_pointer_q == top_pointer_q;
assign full_o = (pointer_overflow) ? (commit_pointer_q == top_pointer_q) : 1'b0;
assign empty = (pointer_overflow) ? 1'b0 : (commit_pointer_q == top_pointer_q);
// rd_clobber output: output currently clobbered destination registers
// but only between commit and issue pointer
@ -129,7 +129,7 @@ always_latch begin : push_instruction_and_wb
// default assignment
top_pointer_n = top_pointer_q;
// if we are not full we can push a new instruction
if (~full_o && decoded_intr_valid_i) begin
if (~full_o && decoded_instr_valid_i) begin
mem[$unsigned(top_pointer_q)] = decoded_instr_i;
top_pointer_n = top_pointer_q + 1;
end
@ -145,6 +145,11 @@ always_latch begin : push_instruction_and_wb
end
end
end
// flush signal
if (flush_i)
mem <= '{default: 0};
end
// issue instruction: advance the issue pointer
@ -153,7 +158,7 @@ always_comb begin : issue_instruction
// provide a combinatorial path in case the scoreboard is empty
if (empty) begin
issue_instr_o = decoded_instr_i;
issue_instr_valid_o = decoded_intr_valid_i;
issue_instr_valid_o = decoded_instr_valid_i;
// if not empty go to scoreboard and get the instruction at the issue pointer
end else begin
issue_instr_o = mem[$unsigned(issue_pointer_q)];
@ -172,7 +177,7 @@ end
always_comb begin: commit_instruction
commit_pointer_n = commit_pointer_q;
// we can always safely output the instruction at which the commit pointer points
// since the scoreboard entry has a valid bit which the commit unit needs to check anyway
// since the scoreboard entry has a valid bit which the commit stage needs to check anyway
commit_instr_o = mem[commit_pointer_q];
if (commit_ready_i) begin
commit_pointer_n = commit_pointer_q + 1;