346 lines
11 KiB
Scala
346 lines
11 KiB
Scala
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package Top {
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import Chisel._
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import Node._;
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import Constants._
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import Instructions._
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class ioDpath extends Bundle()
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{
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val btb_hit = Bool('output);
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val inst = Bits(32, 'output);
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val rs2 = Bits(64, 'output);
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val rs1 = Bits(64, 'output);
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val br_eq = Bool('output);
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val br_lt = Bool('output);
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val br_ltu = Bool('output);
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val div_result_val = Bool('output);
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val div_rdy = Bool('output);
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val mul_result_val = Bool('output);
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val wen = Bool('output);
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val waddr = UFix(5, 'output);
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val alu_out = UFix(64, 'output);
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val exception = Bool('output);
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val status = Bits(8, 'output);
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}
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class ioDpathImem extends Bundle()
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{
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val req_addr = UFix(32, 'output);
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val resp_data = Bits(32, 'input);
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}
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class ioDpathWB extends Bundle()
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{
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val waddr = UFix(5, 'input);
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val wen = Bool('input);
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val wdata = Bits(64, 'input);
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}
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class ioDpathAll extends Bundle()
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{
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val dpath = new ioDpath();
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val host = new ioHost();
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val ctrl = new ioCtrl().flip();
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val debug = new ioDebug();
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val wb = new ioDpathWB();
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val imem = new ioDpathImem();
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}
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class rocketDpath extends Component
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{
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val io = new ioDpathAll();
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val btb = new rocketDpathBTB();
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val if_btb_target = btb.io.target;
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val pcr = new rocketDpathPCR();
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val ex_pcr = pcr.io.r.data;
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val alu = new rocketDpathALU();
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val ex_alu_out = alu.io.out;
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val ex_jr_target = ex_alu_out(31,0);
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val div = new rocketDivider(64);
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val div_result = div.io.div_result_bits;
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val div_result_tag = div.io.div_result_tag;
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val div_result_val = div.io.div_result_val;
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val mul = new rocketMultiplier();
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val mul_result = mul.io.result;
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val mul_result_tag = mul.io.result_tag;
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val mul_result_val = mul.io.result_val;
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val rfile = new rocketDpathRegfile();
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// instruction fetch definitions
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val if_reg_pc = Reg(width = 32, resetVal = UFix(0, 32));
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// instruction decode definitions
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val id_reg_pc = Reg(){UFix(width = 32)};
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val id_reg_pc_plus4 = Reg(){UFix(width = 32)};
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val id_reg_inst = Reg(width = 32, resetVal = NOP);
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// execute definitions
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val ex_reg_pc = Reg(width = 32, resetVal = UFix(0, 32));
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val ex_reg_pc_plus4 = Reg(width = 32, resetVal = UFix(0, 32));
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val ex_reg_inst = Reg(width = 32, resetVal = Bits(0, 32));
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val ex_reg_raddr2 = Reg(width = 5, resetVal = UFix(0, 5));
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val ex_reg_raddr1 = Reg(width = 5, resetVal = UFix(0, 5));
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val ex_reg_rs2 = Reg(width = 64, resetVal = Bits(0, 64));
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val ex_reg_rs1 = Reg(width = 64, resetVal = Bits(0, 64));
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val ex_reg_waddr = Reg(width = 5, resetVal = UFix(0, 5));
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val ex_reg_ctrl_sel_alu2 = Reg(width = 2, resetVal = A2_X);
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val ex_reg_ctrl_sel_alu1 = Reg(width = 1, resetVal = A1_X);
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val ex_reg_ctrl_fn_dw = Reg(width = 1, resetVal = DW_X);
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val ex_reg_ctrl_fn_alu = Reg(width = 4, resetVal = FN_X);
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val ex_reg_ctrl_ll_wb = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_mul_val = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_mul_fn = Reg(width = 3, resetVal = MUL_X);
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val ex_reg_ctrl_div_val = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_div_fn = Reg(width = 4, resetVal = DIV_X);
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val ex_reg_ctrl_sel_wb = Reg(width = 3, resetVal = WB_X);
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val ex_reg_ctrl_wen = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_ren_pcr = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_wen_pcr = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_eret = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_exception = Reg(width = 1, resetVal = Bool(false));
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val ex_reg_ctrl_cause = Reg(width = 5, resetVal = UFix(0,5));
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val ex_wdata = Wire() { Bits() };
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// instruction fetch stage
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val if_pc_plus4 = if_reg_pc + UFix(4, 32);
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val ex_sign_extend =
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Cat(Fill(52, ex_reg_inst(21)), ex_reg_inst(21,10));
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val ex_sign_extend_split =
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Cat(Fill(52, ex_reg_inst(31)), ex_reg_inst(31,27), ex_reg_inst(16,10));
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val branch_adder_rhs =
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Mux(io.ctrl.sel_pc === PC_BR, Cat(ex_sign_extend_split(30,0), UFix(0, 1)),
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Cat(Fill(6, ex_reg_inst(31)), ex_reg_inst(31,7), UFix(0, 1)));
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val ex_branch_target = ex_reg_pc + branch_adder_rhs.toUFix;
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btb.io.correct_target := ex_branch_target;
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val if_next_pc =
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Mux(io.ctrl.sel_pc === PC_4, if_pc_plus4,
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Mux(io.ctrl.sel_pc === PC_BTB, if_btb_target,
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Mux(io.ctrl.sel_pc === PC_EX4, ex_reg_pc_plus4,
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Mux(io.ctrl.sel_pc === PC_BR, ex_branch_target,
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Mux(io.ctrl.sel_pc === PC_J, ex_branch_target,
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Mux(io.ctrl.sel_pc === PC_JR, ex_jr_target.toUFix,
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Mux(io.ctrl.sel_pc === PC_PCR, ex_pcr(31,0).toUFix,
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UFix(0, 32))))))));
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when (!io.host.start){
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if_reg_pc <== UFix(0, 32); //32'hFFFF_FFFC;
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}
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when (!io.ctrl.stallf) {
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if_reg_pc <== if_next_pc;
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}
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io.imem.req_addr :=
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Mux(io.ctrl.stallf, if_reg_pc,
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if_next_pc);
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btb.io.current_pc4 := if_pc_plus4;
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btb.io.hit ^^ io.dpath.btb_hit;
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btb.io.wen ^^ io.ctrl.wen_btb;
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btb.io.correct_pc4 := ex_reg_pc_plus4;
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// instruction decode stage
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when (!io.ctrl.stalld) {
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id_reg_pc <== if_reg_pc;
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id_reg_pc_plus4 <== if_pc_plus4;
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when(io.ctrl.killf) {
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id_reg_inst <== NOP;
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}
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otherwise {
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id_reg_inst <== io.imem.resp_data;
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}
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}
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val id_raddr1 = id_reg_inst(26,22).toUFix;
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val id_raddr2 = id_reg_inst(21,17).toUFix;
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// regfile read
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rfile.io.r0.en ^^ io.ctrl.ren2;
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rfile.io.r0.addr := id_raddr2;
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val id_rdata2 = rfile.io.r0.data;
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rfile.io.r1.en ^^ io.ctrl.ren1;
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rfile.io.r1.addr := id_raddr1;
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val id_rdata1 = rfile.io.r1.data;
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val id_waddr =
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Mux(io.ctrl.div_wb, div_result_tag,
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Mux(io.ctrl.mul_wb, mul_result_tag,
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Mux(io.ctrl.sel_wa === WA_RD, id_reg_inst(31,27).toUFix,
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Mux(io.ctrl.sel_wa === WA_RA, RA,
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UFix(0, 5)))));
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val id_rs1 =
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Mux(io.ctrl.div_wb, div_result,
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Mux(io.ctrl.mul_wb, mul_result,
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Mux(id_raddr1 != UFix(0, 5) && ex_reg_ctrl_wen && id_raddr1 === ex_reg_waddr, ex_wdata,
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id_rdata1)));
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val id_rs2 =
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Mux(id_raddr2 != UFix(0, 5) && ex_reg_ctrl_wen && id_raddr2 === ex_reg_waddr, ex_wdata,
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id_rdata2);
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val id_exception = io.ctrl.xcpt_illegal || io.ctrl.xcpt_privileged || io.ctrl.xcpt_fpu || io.ctrl.xcpt_syscall;
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val id_cause =
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Mux(io.ctrl.xcpt_illegal, UFix(2,5),
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Mux(io.ctrl.xcpt_privileged, UFix(3,5),
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Mux(io.ctrl.xcpt_fpu, UFix(4,5),
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Mux(io.ctrl.xcpt_syscall, UFix(6,5),
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UFix(0,5)))));
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io.dpath.inst := id_reg_inst;
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io.dpath.rs1 := id_rs1;
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io.dpath.rs2 := id_rs2;
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// execute stage
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ex_reg_pc <== id_reg_pc;
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ex_reg_pc_plus4 <== id_reg_pc_plus4;
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ex_reg_inst <== id_reg_inst;
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ex_reg_raddr2 <== id_raddr2;
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ex_reg_raddr1 <== id_raddr1;
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ex_reg_rs2 <== id_rs2;
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ex_reg_rs1 <== id_rs1;
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ex_reg_waddr <== id_waddr;
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ex_reg_ctrl_sel_alu2 <== io.ctrl.sel_alu2;
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ex_reg_ctrl_sel_alu1 <== io.ctrl.sel_alu1.toUFix;
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ex_reg_ctrl_fn_dw <== io.ctrl.fn_dw.toUFix;
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ex_reg_ctrl_fn_alu <== io.ctrl.fn_alu;
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ex_reg_ctrl_mul_fn <== io.ctrl.mul_fn;
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ex_reg_ctrl_div_fn <== io.ctrl.div_fn;
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ex_reg_ctrl_ll_wb <== io.ctrl.div_wb | io.ctrl.mul_wb; // TODO: verify
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ex_reg_ctrl_sel_wb <== io.ctrl.sel_wb;
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ex_reg_ctrl_ren_pcr <== io.ctrl.ren_pcr;
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ex_reg_ctrl_cause <== id_cause;
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when(io.ctrl.killd) {
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ex_reg_ctrl_div_val <== Bool(false);
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ex_reg_ctrl_mul_val <== Bool(false);
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ex_reg_ctrl_wen <== Bool(false);
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ex_reg_ctrl_wen_pcr <== Bool(false);
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ex_reg_ctrl_eret <== Bool(false);
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ex_reg_ctrl_exception <== Bool(false);
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}
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otherwise {
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ex_reg_ctrl_div_val <== io.ctrl.div_val;
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ex_reg_ctrl_mul_val <== io.ctrl.mul_val;
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ex_reg_ctrl_wen <== io.ctrl.wen;
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ex_reg_ctrl_wen_pcr <== io.ctrl.wen_pcr;
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ex_reg_ctrl_eret <== io.ctrl.eret;
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ex_reg_ctrl_exception <== id_exception;
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}
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val ex_alu_in2 =
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Mux(ex_reg_ctrl_sel_alu2 === A2_0, UFix(0, 64),
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Mux(ex_reg_ctrl_sel_alu2 === A2_SEXT, ex_sign_extend,
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Mux(ex_reg_ctrl_sel_alu2 === A2_SPLIT, ex_sign_extend_split,
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Mux(ex_reg_ctrl_sel_alu2 === A2_RS2, ex_reg_rs2,
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UFix(0, 64)))));
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val ex_alu_in1 =
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Mux(ex_reg_ctrl_sel_alu1 === A1_RS1, ex_reg_rs1,
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Mux(ex_reg_ctrl_sel_alu1 === A1_LUI, Cat(Fill(32, ex_reg_inst(26)),ex_reg_inst(26,7),UFix(0, 12)),
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UFix(0, 64)));
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val ex_alu_shamt =
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Cat(ex_alu_in2(5) & ex_reg_ctrl_fn_dw === DW_64, ex_alu_in2(4,0)).toUFix;
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alu.io.dw := ex_reg_ctrl_fn_dw;
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alu.io.fn := ex_reg_ctrl_fn_alu;
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alu.io.shamt := ex_alu_shamt.toUFix;
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alu.io.in2 := ex_alu_in2.toUFix;
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alu.io.in1 := ex_alu_in1.toUFix;
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// divider
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div.io.div_fn := ex_reg_ctrl_div_fn;
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div.io.div_val := ex_reg_ctrl_div_val;
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div.io.div_waddr := ex_reg_waddr;
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div.io.dpath_rs1 := ex_reg_rs1;
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div.io.dpath_rs2 := ex_reg_rs2;
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div.io.div_result_rdy := io.ctrl.div_wb;
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io.dpath.div_rdy := div.io.div_rdy;
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io.dpath.div_result_val := div.io.div_result_val;
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// multiplier
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mul.io.mul_val := ex_reg_ctrl_mul_val;
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mul.io.mul_fn := ex_reg_ctrl_mul_fn;
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mul.io.mul_tag := ex_reg_waddr;
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mul.io.in0 := ex_reg_rs1;
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mul.io.in1 := ex_reg_rs2;
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io.dpath.mul_result_val := mul.io.result_val;
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// processor control register i/o
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pcr.io.host.from_wen ^^ io.host.from_wen;
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pcr.io.host.from ^^ io.host.from;
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pcr.io.host.to ^^ io.host.to;
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pcr.io.r.en := ex_reg_ctrl_ren_pcr | ex_reg_ctrl_exception | ex_reg_ctrl_eret;
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pcr.io.r.addr :=
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Mux(ex_reg_ctrl_exception, PCR_EVEC,
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Mux(ex_reg_ctrl_eret, PCR_EPC,
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ex_reg_raddr2));
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pcr.io.w.addr := ex_reg_raddr2;
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pcr.io.w.en := ex_reg_ctrl_wen_pcr;
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pcr.io.w.data := ex_reg_rs1;
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pcr.io.eret := ex_reg_ctrl_eret;
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pcr.io.exception := ex_reg_ctrl_exception;
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pcr.io.cause := ex_reg_ctrl_cause;
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pcr.io.pc := ex_reg_pc;
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io.dpath.status := pcr.io.status;
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// io.debug ^^ pcr.io.debug;
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io.debug.error_mode := pcr.io.debug.error_mode;
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io.debug.log_control := pcr.io.debug.log_control;
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// branch resolution logic
|
||
|
|
io.dpath.br_eq := (ex_reg_rs1 === ex_reg_rs2);
|
||
|
|
io.dpath.br_ltu := (ex_reg_rs1.toUFix < ex_reg_rs2.toUFix);
|
||
|
|
io.dpath.br_lt :=
|
||
|
|
(~(ex_reg_rs1(63) ^ ex_reg_rs2(63)) & io.dpath.br_ltu |
|
||
|
|
ex_reg_rs1(63) & ~ex_reg_rs2(63)).toBool;
|
||
|
|
|
||
|
|
io.dpath.alu_out := ex_alu_out;
|
||
|
|
|
||
|
|
// writeback select mux
|
||
|
|
ex_wdata :=
|
||
|
|
Mux(ex_reg_ctrl_ll_wb, ex_reg_rs1,
|
||
|
|
Mux(ex_reg_ctrl_sel_wb === WB_PC, ex_reg_pc_plus4,
|
||
|
|
Mux(ex_reg_ctrl_sel_wb === WB_ALU, ex_alu_out,
|
||
|
|
Mux(ex_reg_ctrl_sel_wb === WB_PCR, ex_pcr,
|
||
|
|
Bits(0, 64))))).toBits;
|
||
|
|
|
||
|
|
// regfile write
|
||
|
|
rfile.io.w0.addr := ex_reg_waddr;
|
||
|
|
rfile.io.w0.en := ex_reg_ctrl_wen | ex_reg_ctrl_ll_wb;
|
||
|
|
rfile.io.w0.data := ex_wdata;
|
||
|
|
|
||
|
|
rfile.io.w1.addr ^^ io.wb.waddr;
|
||
|
|
rfile.io.w1.en ^^ io.wb.wen;
|
||
|
|
rfile.io.w1.data ^^ io.wb.wdata;
|
||
|
|
|
||
|
|
// clear scoreboard for "long latency" writebacks
|
||
|
|
io.dpath.wen := ex_reg_ctrl_ll_wb;
|
||
|
|
io.dpath.waddr := ex_reg_waddr;
|
||
|
|
|
||
|
|
// exception signal to control (for NPC select)
|
||
|
|
io.dpath.exception := ex_reg_ctrl_exception;
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|