tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.module TopModule (
input logic clk,
input logic rst,
input logic halt_req_i,
input logic resume_req_i,
input logic step_req_i,
input logic dbus_ren_i,
input logic [1:0] dbus_addr_i,
output logic [7:0] dbus_rdata_o,
output logic halted_o,
output logic fetch_o
);
// Control FSM states.
// RUN : core running (fetch high)
// HALT_A/B : two "drain" cycles after a halt request keep fetch high
// HALTED : core stopped
// STEP_WAIT : latched a step request, still halted this cycle
// STEP_GO : the single fetch cycle produced by a step
// RES_WAIT : latched a resume request, still halted this cycle
typedef enum logic [2:0] {
RUN = 3'd0,
HALT_A = 3'd1,
HALT_B = 3'd2,
HALTED = 3'd3,
STEP_WAIT = 3'd4,
STEP_GO = 3'd5,
RES_WAIT = 3'd6
} state_e;
state_e state, next_state;
// Next-state logic.
always_comb begin
next_state = state;
unique case (state)
RUN: next_state = halt_req_i ? HALT_A : RUN;
HALT_A: next_state = HALT_B;
HALT_B: next_state = HALTED;
HALTED: begin
if (halt_req_i && step_req_i) next_state = HALTED; // conflict: stay halted
else if (step_req_i) next_state = STEP_WAIT;
else if (resume_req_i) next_state = RES_WAIT;
else next_state = HALTED;
end
STEP_WAIT: next_state = STEP_GO;
STEP_GO: next_state = HALTED;
RES_WAIT: next_state = RUN;
default: next_state = RUN;
endcase
end
// Moore outputs for a given state.
function automatic logic f_fetch(state_e s);
unique case (s)
RUN, HALT_A, HALT_B, STEP_GO: f_fetch = 1'b1;
default: f_fetch = 1'b0;
endcase
endfunction
function automatic logic f_halted(state_e s);
unique case (s)
HALTED, STEP_WAIT, RES_WAIT: f_halted = 1'b1;
default: f_halted = 1'b0;
endcase
endfunction
// Debug-port memory contents.
function automatic logic [7:0] f_mem(logic [1:0] a);
unique case (a)
2'd0: f_mem = 8'h5A;
2'd1: f_mem = 8'hC3;
2'd2: f_mem = 8'h0F;
2'd3: f_mem = 8'h96;
default: f_mem = 8'h00;
endcase
endfunction
// Debug-read pipeline: address is captured, data presented one cycle later.
logic ren_q;
logic [1:0] addr_q;
always_ff @(posedge clk) begin
if (rst) begin
state <= RUN;
fetch_o <= 1'b0;
halted_o <= 1'b0;
dbus_rdata_o <= 8'h00;
ren_q <= 1'b0;
addr_q <= 2'd0;
end else begin
state <= next_state;
fetch_o <= f_fetch(next_state);
halted_o <= f_halted(next_state);
ren_q <= dbus_ren_i;
addr_q <= dbus_addr_i;
if (ren_q)
dbus_rdata_o <= f_mem(addr_q);
end
end
endmodule
Check for available Verilog simulators
which iverilog vvp verilator 2>/dev/null; echo "---done---"
/usr/bin/iverilog /usr/bin/vvp ---done--- [stdout] /usr/bin/iverilog /usr/bin/vvp ---done---
module tb;
logic clk=0, rst;
logic halt_req_i, resume_req_i, step_req_i, dbus_ren_i;
logic [1:0] dbus_addr_i;
logic [7:0] dbus_rdata_o;
logic halted_o, fetch_o;
integer errors = 0;
TopModule dut(.*);
always #5 clk = ~clk;
task chk(input string what, input logic got, input logic exp);
if (got !== exp) begin
$display("FAIL %s: got %b exp %b", what, got, exp);
errors++;
end
endtask
task chk8(input string what, input logic [7:0] got, input logic [7:0] exp);
if (got !== exp) begin
$display("FAIL %s: got %02h exp %02h", what, got, exp);
errors++;
end
endtask
// step one clock (drive inputs before the edge)
task step();
@(negedge clk); // settle: we set inputs on negedge, sample on posedge
endtask
initial begin
// defaults
halt_req_i=0; resume_req_i=0; step_req_i=0; dbus_ren_i=0; dbus_addr_i=0;
rst=1;
@(negedge clk); // apply reset before first posedge
@(posedge clk); #1; // reset edge
chk("reset fetch", fetch_o, 0);
chk("reset halted", halted_o, 0);
chk8("reset rdata", dbus_rdata_o, 8'h00);
rst=0;
// Run steadily: after 1 cycle should be running
@(posedge clk); #1;
chk("run fetch", fetch_o, 1);
chk("run halted", halted_o, 0);
@(posedge clk); #1;
chk("run fetch2", fetch_o, 1);
chk("run halted2", halted_o, 0);
// ---- HALT ----
// assert halt before edge E
halt_req_i = 1;
@(posedge clk); #1; // edge E
halt_req_i = 0;
chk("E fetch", fetch_o, 1);
chk("E halted", halted_o, 0);
@(posedge clk); #1; // E+1
chk("E+1 fetch", fetch_o, 1);
chk("E+1 halted", halted_o, 0);
@(posedge clk); #1; // E+2
chk("E+2 fetch", fetch_o, 0);
chk("E+2 halted", halted_o, 1);
@(posedge clk); #1; // E+3
chk("E+3 fetch", fetch_o, 0);
chk("E+3 halted", halted_o, 1);
// ---- STEP (while halted) ----
step_req_i = 1;
@(posedge clk); #1; // edge S
step_req_i = 0;
chk("S fetch", fetch_o, 0);
chk("S halted", halted_o, 1);
@(posedge clk); #1; // S+1
chk("S+1 fetch", fetch_o, 1);
chk("S+1 halted", halted_o, 0);
@(posedge clk); #1; // S+2
chk("S+2 fetch", fetch_o, 0);
chk("S+2 halted", halted_o, 1);
// ---- halt+step both high while halted -> stay halted, fetch low ----
halt_req_i = 1; step_req_i = 1;
@(posedge clk); #1;
chk("conflict fetch", fetch_o, 0);
chk("conflict halted", halted_o, 1);
@(posedge clk); #1;
chk("conflict2 fetch", fetch_o, 0);
chk("conflict2 halted", halted_o, 1);
halt_req_i = 0; step_req_i = 0;
// ---- RESUME (while halted) ----
resume_req_i = 1;
@(posedge clk); #1; // edge G
resume_req_i = 0;
chk("G fetch", fetch_o, 0);
chk("G halted", halted_o, 1);
@(posedge clk); #1; // G+1
chk("G+1 fetch", fetch_o, 1);
chk("G+1 halted", halted_o, 0);
@(posedge clk); #1; // G+2
chk("G+2 fetch", fetch_o, 1);
chk("G+2 halted", halted_o, 0);
// ---- DBUS read while running, single-cycle pulse per address ----
// read addr 2
dbus_ren_i = 1; dbus_addr_i = 2;
@(posedge clk); #1; // edge R
dbus_ren_i = 0;
// at R rdata not yet updated
@(posedge clk); #1; // R+1
chk8("dbus addr2 R+1", dbus_rdata_o, 8'h0F);
@(posedge clk); #1; // hold while ren low
chk8("dbus addr2 hold", dbus_rdata_o, 8'h0F);
// read addr 0
dbus_ren_i = 1; dbus_addr_i = 0;
@(posedge clk); #1;
dbus_ren_i = 0;
@(posedge clk); #1;
chk8("dbus addr0", dbus_rdata_o, 8'h5A);
// read addr 1
dbus_ren_i = 1; dbus_addr_i = 1;
@(posedge clk); #1;
dbus_ren_i = 0;
@(posedge clk); #1;
chk8("dbus addr1", dbus_rdata_o, 8'hC3);
// read addr 3
dbus_ren_i = 1; dbus_addr_i = 3;
@(posedge clk); #1;
dbus_ren_i = 0;
@(posedge clk); #1;
chk8("dbus addr3", dbus_rdata_o, 8'h96);
@(posedge clk); #1;
chk8("dbus addr3 hold", dbus_rdata_o, 8'h96);
// ---- DBUS read while halted (any state) ----
halt_req_i = 1;
@(posedge clk); #1; halt_req_i = 0;
@(posedge clk); #1;
@(posedge clk); #1; // now halted
chk("halted for dbus", halted_o, 1);
dbus_ren_i = 1; dbus_addr_i = 2;
@(posedge clk); #1;
dbus_ren_i = 0;
@(posedge clk); #1;
chk8("dbus halted addr2", dbus_rdata_o, 8'h0F);
chk("still halted", halted_o, 1);
if (errors==0) $display("ALL TESTS PASSED");
else $display("%0d ERRORS", errors);
$finish;
end
endmodule
Compile and run the testbench
iverilog -g2012 -o sim dut.sv tb.sv 2>&1 && vvp sim 2>&1
Exit code 1 dut.sv:37: error: This assignment requires an explicit cast. 1 error(s) during elaboration. [error] tool reported failure
/app/dut.sv
RUN: next_state = halt_req_i ? HALT_A : RUN;
RUN: if (halt_req_i) next_state = HALT_A; else next_state = RUN;
Recompile and run
iverilog -g2012 -o sim dut.sv tb.sv 2>&1 && vvp sim 2>&1
dut.sv:55: vvp.tgt sorry: Case unique/unique0 qualities are ignored. dut.sv:62: vvp.tgt sorry: Case unique/unique0 qualities are ignored. dut.sv:70: vvp.tgt sorry: Case unique/unique0 qualities are ignored. dut.sv:36: vvp.tgt sorry: Case unique/unique0 qualities are ignored. ALL TESTS PASSED tb.sv:150: $finish called at 306 (1s) [stdout] dut.sv:55: vvp.tgt sorry: Case unique/unique0 qualities are ignored. dut.sv:62: vvp.tgt sorry: Case unique/unique0 qualities are ignored. dut.sv:70: vvp.tgt sorry: Case unique/unique0 qualities are ignored. dut.sv:36: vvp.tgt sorry: Case unique/unique0 qualities are ignored. ALL TESTS PASSED tb.sv:150: $finish called at 306 (1s)
Remove testbench and sim binary
rm -f /app/tb.sv /app/sim; ls /app
dut.sv [stdout] dut.sv
No file changes, the agent left the workspace untouched.
TEST dut_present: PASS (/app/dut.sv exists)
TEST dut_forbidden: PASS (no forbidden constructs)
TEST dut_compiles: PASS (compiled with held-back reference/testbench)
TEST simulation_completed: PASS (Mismatches: 1196 in 2301 samples)
TEST reference_equivalence: FAIL (1196 mismatches in 2301 samples)
{"score": 0.000000, "results_file": "/tmp/h2t-grader-home.3KFLGJ/runtime/cb_verifier_319-20004-2813-24174_319/results.jsonl"}Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_2966dd49536643b2. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.
Trial trial_2966dd49536643b2 · verifier authoritative; classifier explanatory.