riscv/rocket-chip
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Begin integer unit clean-up

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...to make it easier to generate the superscalar version of the core.
This commit is contained in:
Andrew Waterman
2013-12-09 15:06:13 -08:00
parent 16d5250924
commit da3135ac9b
6 changed files with 199 additions and 206 deletions
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92
rocket/src/main/scala/ctrl.scala
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@@ -11,8 +11,7 @@ class CtrlDpathIO extends Bundle()
// outputs to datapath
val sel_pc = UInt(OUTPUT, 3);
val killd = Bool(OUTPUT);
val ren2 = Bool(OUTPUT);
val ren1 = Bool(OUTPUT);
val ren = Vec.fill(2)(Bool(OUTPUT))
val sel_alu2 = UInt(OUTPUT, 3)
val sel_alu1 = UInt(OUTPUT, 2)
val sel_imm = UInt(OUTPUT, 3)
@@ -37,8 +36,9 @@ class CtrlDpathIO extends Bundle()
val ex_rs2_val = Bool(OUTPUT)
val ex_rocc_val = Bool(OUTPUT)
val mem_rocc_val = Bool(OUTPUT)
val mem_ll_bypass_rs1 = Bool(OUTPUT)
val mem_ll_bypass_rs2 = Bool(OUTPUT)
val bypass = Vec.fill(2)(Bool(OUTPUT))
val bypass_src = Vec.fill(2)(Bits(OUTPUT, SZ_BYP))
val ll_ready = Bool(OUTPUT)
// exception handling
val retire = Bool(OUTPUT)
val exception = Bool(OUTPUT);
@@ -50,11 +50,11 @@ class CtrlDpathIO extends Bundle()
val ex_br_type = Bits(OUTPUT, SZ_BR)
val ex_br_taken = Bool(INPUT)
val div_mul_rdy = Bool(INPUT)
val mem_ll_wb = Bool(INPUT)
val mem_ll_waddr = UInt(INPUT, 5)
val ex_waddr = UInt(INPUT, 5); // write addr from execute stage
val mem_waddr = UInt(INPUT, 5); // write addr from memory stage
val wb_waddr = UInt(INPUT, 5); // write addr from writeback stage
val ll_wen = Bool(INPUT)
val ll_waddr = UInt(INPUT, 5)
val ex_waddr = UInt(INPUT, 5)
val mem_waddr = UInt(INPUT, 5)
val wb_waddr = UInt(INPUT, 5)
val status = new Status().asInput
val fp_sboard_clr = Bool(INPUT);
val fp_sboard_clra = UInt(INPUT, 5);
@@ -543,9 +543,8 @@ class Control(implicit conf: RocketConfiguration) extends Module
(mem_reg_mem_val && io.dmem.xcpt.pf.st, UInt(11))))
val fpu_kill_mem = mem_reg_fp_val && io.fpu.nack_mem
val ll_wb_kill_mem = io.dpath.mem_ll_wb && (mem_reg_wen || mem_reg_fp_wen || mem_reg_rocc_val || mem_reg_csr != CSR.N)
val replay_mem = ll_wb_kill_mem || mem_reg_replay || fpu_kill_mem
val killm_common = ll_wb_kill_mem || take_pc_wb || mem_reg_xcpt || !mem_reg_valid
val replay_mem = mem_reg_replay || fpu_kill_mem
val killm_common = take_pc_wb || mem_reg_xcpt || !mem_reg_valid
ctrl_killm := killm_common || mem_xcpt || fpu_kill_mem
wb_reg_replay := replay_mem && !take_pc_wb
@@ -577,23 +576,22 @@ class Control(implicit conf: RocketConfiguration) extends Module
wb_reg_rocc_val := mem_reg_rocc_val
}
val replay_wb = io.dmem.resp.bits.nack || wb_reg_replay ||
io.dpath.csr_replay || Bool(!conf.rocc.isEmpty) && wb_reg_rocc_val && !io.rocc.cmd.ready
val replay_wb_common =
io.dmem.resp.bits.nack || wb_reg_replay ||
io.dpath.ll_wen && wb_reg_wen || io.dpath.csr_replay
val wb_rocc_val = wb_reg_rocc_val && !replay_wb_common
val replay_wb = replay_wb_common || wb_reg_rocc_val && !io.rocc.cmd.ready
class Scoreboard(n: Int)
{
val r = Reg(init=Bits(0, n))
private var _next = r
private var cur = r
var ens = Bool(false)
def set(en: Bool, addr: UInt): Unit = update(en, _next | mask(en, addr))
def clear(en: Bool, addr: UInt): Unit = {
val m = ~mask(en, addr)
update(en, _next & m)
//cur = cur & m
}
def read(addr: UInt) = r(addr)
def readBypassed(addr: UInt) = cur(addr)
def clear(en: Bool, addr: UInt): Unit = update(en, _next & ~mask(en, addr))
def read(addr: UInt): Bool = r(addr)
def readBypassed(addr: UInt): Bool = _next(addr)
private val r = Reg(init=Bits(0, n))
private var _next = r
private var ens = Bool(false)
private def mask(en: Bool, addr: UInt) = Mux(en, UInt(1) << addr, UInt(0))
private def update(en: Bool, update: UInt) = {
_next = update
@@ -604,7 +602,7 @@ class Control(implicit conf: RocketConfiguration) extends Module
val sboard = new Scoreboard(32)
sboard.set((wb_reg_div_mul_val || wb_dcache_miss || wb_reg_rocc_val) && io.dpath.wb_wen, io.dpath.wb_waddr)
sboard.clear(io.dpath.mem_ll_wb, io.dpath.mem_ll_waddr)
sboard.clear(io.dpath.ll_wen, io.dpath.ll_waddr)
val id_stall_fpu = if (conf.fpu) {
val fp_sboard = new Scoreboard(32)
@@ -613,10 +611,10 @@ class Control(implicit conf: RocketConfiguration) extends Module
fp_sboard.clear(io.fpu.sboard_clr, io.fpu.sboard_clra)
id_csr_en && !io.fpu.fcsr_rdy ||
io.fpu.dec.ren1 && fp_sboard.readBypassed(id_raddr1) ||
io.fpu.dec.ren2 && fp_sboard.readBypassed(id_raddr2) ||
io.fpu.dec.ren3 && fp_sboard.readBypassed(id_raddr3) ||
io.fpu.dec.wen && fp_sboard.readBypassed(id_waddr)
io.fpu.dec.ren1 && fp_sboard.read(id_raddr1) ||
io.fpu.dec.ren2 && fp_sboard.read(id_raddr2) ||
io.fpu.dec.ren3 && fp_sboard.read(id_raddr3) ||
io.fpu.dec.wen && fp_sboard.read(id_waddr)
} else Bool(false)
// write CAUSE CSR on an exception
@@ -638,6 +636,18 @@ class Control(implicit conf: RocketConfiguration) extends Module
io.imem.req.bits.taken := !ex_reg_btb_hit || ex_reg_jalr
io.imem.req.valid := take_pc
val bypassDst = Array(id_raddr1, id_raddr2)
val bypassSrc = Array.fill(NBYP)((Bool(true), UInt(0)))
bypassSrc(BYP_EX) = (ex_reg_wen, io.dpath.ex_waddr)
bypassSrc(BYP_MEM) = (mem_reg_wen && !mem_reg_mem_val, io.dpath.mem_waddr)
bypassSrc(BYP_DC) = (mem_reg_wen, io.dpath.mem_waddr)
val doBypass = bypassDst.map(d => bypassSrc.map(s => s._1 && s._2 === d))
for (i <- 0 until io.dpath.bypass.size) {
io.dpath.bypass(i) := doBypass(i).reduce(_||_)
io.dpath.bypass_src(i) := PriorityEncoder(doBypass(i))
}
// stall for RAW/WAW hazards on PCRs, loads, AMOs, and mul/div in execute stage.
val data_hazard_ex = ex_reg_wen &&
(id_renx1.toBool && id_raddr1 === io.dpath.ex_waddr ||
@@ -669,24 +679,17 @@ class Control(implicit conf: RocketConfiguration) extends Module
id_load_use := mem_reg_mem_val && (data_hazard_mem || fp_data_hazard_mem)
// stall for RAW/WAW hazards on load/AMO misses and mul/div in writeback.
val data_hazard_wb = wb_reg_wen &&
(id_raddr1 != UInt(0) && id_renx1 && (id_raddr1 === io.dpath.wb_waddr) ||
id_raddr2 != UInt(0) && id_renx2 && (id_raddr2 === io.dpath.wb_waddr) ||
id_waddr != UInt(0) && id_wen && (id_waddr === io.dpath.wb_waddr))
val fp_data_hazard_wb = wb_reg_fp_wen &&
(io.fpu.dec.ren1 && id_raddr1 === io.dpath.wb_waddr ||
io.fpu.dec.ren2 && id_raddr2 === io.dpath.wb_waddr ||
io.fpu.dec.ren3 && id_raddr3 === io.dpath.wb_waddr ||
io.fpu.dec.wen && id_waddr === io.dpath.wb_waddr)
val id_wb_hazard = data_hazard_wb && (wb_dcache_miss || wb_reg_div_mul_val || wb_reg_rocc_val) ||
fp_data_hazard_wb && (wb_dcache_miss || wb_reg_fp_val)
val id_wb_hazard = fp_data_hazard_wb && (wb_dcache_miss || wb_reg_fp_val)
io.dpath.mem_ll_bypass_rs1 := io.dpath.mem_ll_wb && io.dpath.mem_ll_waddr === id_raddr1
io.dpath.mem_ll_bypass_rs2 := io.dpath.mem_ll_wb && io.dpath.mem_ll_waddr === id_raddr2
val id_sboard_hazard =
(id_raddr1 != UInt(0) && id_renx1 && sboard.read(id_raddr1) && !io.dpath.mem_ll_bypass_rs1 ||
id_raddr2 != UInt(0) && id_renx2 && sboard.read(id_raddr2) && !io.dpath.mem_ll_bypass_rs2 ||
id_waddr != UInt(0) && id_wen && sboard.read(id_waddr))
(id_raddr1 != UInt(0) && id_renx1 && sboard.readBypassed(id_raddr1) ||
id_raddr2 != UInt(0) && id_renx2 && sboard.readBypassed(id_raddr2) ||
id_waddr != UInt(0) && id_wen && sboard.readBypassed(id_waddr))
val ctrl_stalld =
id_ex_hazard || id_mem_hazard || id_wb_hazard || id_sboard_hazard ||
@@ -702,8 +705,8 @@ class Control(implicit conf: RocketConfiguration) extends Module
io.dpath.mem_load := mem_reg_mem_val && mem_reg_wen
io.dpath.wb_load := wb_reg_mem_val && wb_reg_wen
io.dpath.ren2 := id_renx2.toBool;
io.dpath.ren1 := id_renx1.toBool;
io.dpath.ren(1) := id_renx2
io.dpath.ren(0) := id_renx1
io.dpath.sel_alu2 := id_sel_alu2.toUInt
io.dpath.sel_alu1 := id_sel_alu1.toUInt
io.dpath.sel_imm := id_sel_imm.toUInt
@@ -717,6 +720,7 @@ class Control(implicit conf: RocketConfiguration) extends Module
io.dpath.ex_predicted_taken := ex_reg_btb_hit
io.dpath.ex_wen := ex_reg_wen;
io.dpath.mem_wen := mem_reg_wen;
io.dpath.ll_ready := !wb_reg_wen
io.dpath.wb_wen := wb_reg_wen && !replay_wb
io.dpath.retire := wb_reg_valid && !replay_wb
io.dpath.csr := wb_reg_csr
@@ -737,5 +741,5 @@ class Control(implicit conf: RocketConfiguration) extends Module
io.dmem.req.bits.typ := ex_reg_mem_type
io.dmem.req.bits.phys := Bool(false)
io.rocc.cmd.valid := wb_reg_rocc_val
io.rocc.cmd.valid := wb_rocc_val
}