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`include "core/uarch.sv"
module core_control_stall
(
input logic clk,
rst_n,
input insn_decode dec,
input ctrl_cycle next_cycle,
input logic final_update_flags,
update_flags,
final_writeback,
writeback,
input reg_num final_rd,
output logic stall,
bubble,
next_bubble
);
logic pc_writeback_hazard, flags_hazard, data_hazard, rn_hazard,
snd_hazard, flags_dependency, updating_flags;
assign stall = next_cycle != ISSUE || next_bubble;
assign next_bubble = pc_writeback_hazard || flags_hazard || data_hazard;
assign pc_writeback_hazard = final_writeback && final_rd == `R15;
assign flags_hazard = flags_dependency && updating_flags;
assign data_hazard = final_writeback && (rn_hazard || snd_hazard);
assign rn_hazard = dec.data.uses_rn && (final_rd == dec.data.rn || dec.data.rn == `R15);
assign snd_hazard = !dec.snd.is_imm && (dec.snd.r == final_rd || dec.snd.r == `R15);
assign flags_dependency = dec.psr.update_flags || dec.ctrl.conditional;
assign updating_flags = final_update_flags || update_flags;
always_ff @(posedge clk or negedge rst_n)
bubble <= !rst_n ? 0 : next_cycle == ISSUE && next_bubble;
endmodule
|
