riscv/rocket-chip
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remove pc+4 piperegs and add new ex pc+4 adder

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This commit is contained in:
Andrew Waterman 2012-02-02 13:33:27 -08:00
parent 01a156eb98
commit 99a959e6b1
1 changed files with 4 additions and 7 deletions
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11
rocket/src/main/scala/dpath.scala
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@ -70,12 +70,10 @@ class rocketDpath extends Component
val id_reg_valid = Reg(resetVal = Bool(false));
val id_reg_inst = Reg(resetVal = NOP);
val id_reg_pc = Reg() { UFix(width = VADDR_BITS+1) };
val id_reg_pc_plus4 = Reg() { UFix(width = VADDR_BITS+1) };
// execute definitions
val ex_reg_valid = Reg(resetVal = Bool(false));
val ex_reg_pc = Reg() { UFix() };
val ex_reg_pc_plus4 = Reg() { UFix() };
val ex_reg_inst = Reg() { Bits() };
val ex_reg_raddr2 = Reg() { UFix() };
val ex_reg_rs2 = Reg() { Bits() };
@ -127,6 +125,7 @@ class rocketDpath extends Component
// instruction fetch stage
val if_pc_plus4 = if_reg_pc + UFix(4);
val ex_pc_plus4 = ex_reg_pc + UFix(4);
val ex_sign_extend =
Cat(Fill(52, ex_reg_inst(21)), ex_reg_inst(21,10));
val ex_sign_extend_split =
@ -145,7 +144,7 @@ class rocketDpath extends Component
val if_next_pc =
Mux(io.ctrl.sel_pc === PC_BTB, Cat(if_btb_target(VADDR_BITS-1), if_btb_target),
Mux(io.ctrl.sel_pc === PC_EX4, ex_reg_pc_plus4,
Mux(io.ctrl.sel_pc === PC_EX4, ex_pc_plus4,
Mux(io.ctrl.sel_pc === PC_BR, ex_branch_target,
Mux(io.ctrl.sel_pc === PC_JR, ex_jr_target_extended,
Mux(io.ctrl.sel_pc === PC_PCR, wb_reg_wdata(VADDR_BITS,0), // only used for ERET
@ -167,13 +166,12 @@ class rocketDpath extends Component
btb.io.hit <> io.ctrl.btb_hit;
btb.io.wen <> io.ctrl.wen_btb;
btb.io.clr <> io.ctrl.clr_btb;
btb.io.correct_pc4 := ex_reg_pc_plus4;
btb.io.correct_pc4 := ex_pc_plus4;
io.ctrl.btb_match := id_reg_pc === jr_br_target;
// instruction decode stage
when (!io.ctrl.stalld) {
id_reg_pc <== if_reg_pc;
id_reg_pc_plus4 <== if_pc_plus4;
when(io.ctrl.killf) {
id_reg_inst <== NOP;
id_reg_valid <== Bool(false);
@ -231,7 +229,6 @@ class rocketDpath extends Component
// execute stage
ex_reg_pc <== id_reg_pc;
ex_reg_pc_plus4 <== id_reg_pc_plus4;
ex_reg_inst <== id_reg_inst;
ex_reg_raddr2 <== id_raddr2;
ex_reg_rs2 <== id_rs2;
@ -351,7 +348,7 @@ class rocketDpath extends Component
// writeback select mux
ex_wdata :=
Mux(ex_reg_ctrl_ll_wb || ex_reg_ctrl_wen_pcr, ex_reg_rs1,
Mux(ex_reg_ctrl_sel_wb === WB_PC, Cat(Fill(64-VADDR_BITS, ex_reg_pc_plus4(VADDR_BITS-1)), ex_reg_pc_plus4),
Mux(ex_reg_ctrl_sel_wb === WB_PC, Cat(Fill(64-VADDR_BITS, ex_pc_plus4(VADDR_BITS-1)), ex_pc_plus4),
Mux(ex_reg_ctrl_sel_wb === WB_PCR, ex_pcr,
Mux(ex_reg_ctrl_sel_wb === WB_TSC, tsc_reg,
Mux(ex_reg_ctrl_sel_wb === WB_IRT, irt_reg,