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`include "core/psr.sv"
`include "core/uarch.sv"
module core_cycles
(
input logic clk,
decode_execute,
decode_writeback,
decode_branch,
input reg_num decode_rd,
input ptr decode_branch_offset,
input alu_op decode_data_op,
input ptr fetch_insn_pc,
input psr_flags alu_flags,
output logic stall,
branch,
writeback,
output reg_num rd,
output ptr branch_target,
pc,
pc_visible,
output psr_mode reg_mode,
output alu_op data_op,
output psr_flags flags,
next_flags
);
enum
{
EXECUTE
} cycle, next_cycle;
assign stall = next_cycle != EXECUTE;
assign pc_visible = pc + 2;
assign next_cycle = EXECUTE; //TODO
assign next_flags = alu_flags; //TODO
assign reg_mode = `MODE_SVC; //TODO
always_ff @(posedge clk) begin
cycle <= next_cycle;
stall <= next_cycle != EXECUTE;
flags <= next_flags;
if(next_cycle == EXECUTE) begin
branch <= 0;
writeback <= 0;
branch_target <= 30'bxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx;
if(decode_execute) begin
branch <= decode_branch;
writeback <= decode_writeback;
branch_target <= pc_visible + decode_branch_offset;
end
pc <= fetch_insn_pc;
rd <= decode_rd;
data_op <= decode_data_op;
end
end
initial begin
cycle = EXECUTE;
branch = 1;
writeback = 0;
branch_target = 30'd0;
pc = 0;
end
endmodule
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