fix 32-bit divider bug
thanks, torture! also, tidied up the code a bit.
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03ee49f424
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@ -11,14 +11,14 @@ class ioDivider(width: Int) extends Bundle {
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val div_rdy = Bool(OUTPUT);
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val dw = UFix(1, INPUT);
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val div_fn = UFix(2, INPUT);
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val div_waddr = UFix(5, INPUT);
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val dpath_rs1 = Bits(width, INPUT);
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val dpath_rs2 = Bits(width, INPUT);
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val div_tag = UFix(5, INPUT);
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val in0 = Bits(width, INPUT);
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val in1 = Bits(width, INPUT);
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// responses
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val div_result_bits = Bits(width, OUTPUT);
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val div_result_tag = UFix(5, OUTPUT);
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val div_result_val = Bool(OUTPUT);
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val div_result_rdy = Bool(INPUT);
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val result = Bits(width, OUTPUT);
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val result_tag = UFix(5, OUTPUT);
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val result_val = Bool(OUTPUT);
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val result_rdy = Bool(INPUT);
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}
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// class ioDivider extends Bundle {
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@ -41,12 +41,11 @@ class rocketDivider(width : Int) extends Component {
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val s_ready :: s_neg_inputs :: s_busy :: s_neg_outputs :: s_done :: Nil = Enum(5) { UFix() };
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val state = Reg(resetVal = s_ready);
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val count_bits = java.math.BigInteger.valueOf(width).bitLength();
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val count = Reg() { UFix() };
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val divby0 = Reg() { Bool() };
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val neg_quo = Reg() { Bool() };
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val neg_rem = Reg() { Bool() };
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val reg_waddr = Reg() { UFix() };
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val reg_tag = Reg() { UFix() };
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val rem = Reg() { Bool() };
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val half = Reg() { Bool() };
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@ -75,30 +74,28 @@ class rocketDivider(width : Int) extends Component {
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}
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is (s_neg_outputs) { state <== s_done; }
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is (s_done) {
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when (io.div_result_rdy) { state <== s_ready; }
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when (io.result_rdy) { state <== s_ready; }
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}
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}
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// if we're doing 32-bit unsigned division, then we don't want the 32-bit
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// inputs to be sign-extended.
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val in_lhs = Mux(((io.dw === DW_32) && !tc),
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Cat(Fill(width/2, UFix(0,1)), io.dpath_rs1(width/2-1, 0)),
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io.dpath_rs1).toUFix;
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val lhs_sign = tc && Mux(io.dw === DW_64, io.in0(width-1), io.in0(width/2-1)).toBool
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val lhs_hi = Mux(io.dw === DW_64, io.in0(width-1,width/2), Fill(width/2, lhs_sign))
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val lhs_in = Cat(lhs_hi, io.in0(width/2-1,0))
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val in_rhs = Mux(((io.dw === DW_32) && !tc),
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Cat(Fill(width/2, UFix(0,1)), io.dpath_rs2(width/2-1, 0)),
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io.dpath_rs2).toUFix;
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val rhs_sign = tc && Mux(io.dw === DW_64, io.in1(width-1), io.in1(width/2-1)).toBool
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val rhs_hi = Mux(io.dw === DW_64, io.in1(width-1,width/2), Fill(width/2, rhs_sign))
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val rhs_in = Cat(rhs_hi, io.in1(width/2-1,0))
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when ((state === s_ready) && io.div_val) {
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count <== UFix(0, count_bits);
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count <== UFix(0, log2up(width+1));
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half <== (io.dw === DW_32);
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neg_quo <== Bool(false);
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neg_rem <== Bool(false);
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rem <== (io.div_fn === DIV_R) || (io.div_fn === DIV_RU);
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reg_waddr <== io.div_waddr;
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reg_tag <== io.div_tag;
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divby0 <== Bool(true);
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divisor <== in_rhs;
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remainder <== Cat(Fill(width+1, UFix(0,1)), in_lhs).toUFix;
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divisor <== rhs_in.toUFix;
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remainder <== Cat(UFix(0,width+1), lhs_in).toUFix;
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}
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when (state === s_neg_inputs) {
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@ -135,10 +132,11 @@ class rocketDivider(width : Int) extends Component {
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val result = Mux(rem, remainder(2*width, width+1), remainder(width-1,0));
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io.div_result_bits := Mux(half, Cat(Fill(width/2, result(width/2-1)), result(width/2-1,0)), result);
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io.result := Mux(half, Cat(Fill(width/2, result(width/2-1)), result(width/2-1,0)), result);
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io.result_tag := reg_tag;
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io.result_val := (state === s_done);
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io.div_rdy := (state === s_ready);
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io.div_result_tag := reg_waddr;
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io.div_result_val := (state === s_done);
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}
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}
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@ -61,9 +61,9 @@ class rocketDpath extends Component
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val ex_alu_adder_out = alu.io.adder_out;
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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 div_result = div.io.result;
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val div_result_tag = div.io.result_tag;
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val div_result_val = div.io.result_val;
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val mul = new rocketMultiplier();
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val mul_result = mul.io.result;
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@ -275,13 +275,13 @@ class rocketDpath extends Component
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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_kill := io.ctrl.killm;
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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 := !dmem_resp_replay
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div.io.div_tag := ex_reg_waddr;
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div.io.in0 := ex_reg_rs1;
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div.io.in1 := ex_reg_rs2;
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div.io.result_rdy:= !dmem_resp_replay
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io.ctrl.div_rdy := div.io.div_rdy;
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io.ctrl.div_result_val := div.io.div_result_val;
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io.ctrl.div_result_val := div.io.result_val;
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// multiplier
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mul.io.mul_val := ex_reg_ctrl_mul_val;
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@ -294,7 +294,7 @@ class rocketDpath extends Component
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io.ctrl.mul_rdy := mul.io.mul_rdy
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io.ctrl.mul_result_val := mul.io.result_val;
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mul.io.result_rdy := !dmem_resp_replay && !div.io.div_result_val
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mul.io.result_rdy := !dmem_resp_replay && !div.io.result_val
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io.ctrl.ex_waddr := ex_reg_waddr; // for load/use hazard detection & bypass control
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