riscv/rocket-chip
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Make FPU pipeline depths configurable

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This commit is contained in:
Andrew Waterman 2014-02-28 13:39:35 -08:00
parent 98b830201a
commit c7110c8389
5 changed files with 17 additions and 14 deletions
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4
rocket/src/main/scala/core.scala
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@ -21,8 +21,8 @@ class Core(implicit conf: RocketConfiguration) extends Module
val ctrl = Module(new Control)
val dpath = Module(new Datapath)
val fpu: FPU = if (conf.fpu) {
val fpu = Module(new FPU(2,3))
val fpu: FPU = if (!conf.fpu.isEmpty) {
val fpu = Module(new FPU(conf.fpu.get))
dpath.io.fpu <> fpu.io.dpath
ctrl.io.fpu <> fpu.io.ctrl
fpu

8
rocket/src/main/scala/ctrl.scala
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@ -318,7 +318,7 @@ class Control(implicit conf: RocketConfiguration) extends Module
}
var decode_table = XDecode.table
if (conf.fpu) decode_table ++= FDecode.table
if (!conf.fpu.isEmpty) decode_table ++= FDecode.table
if (!conf.rocc.isEmpty) decode_table ++= RoCCDecode.table
val cs = DecodeLogic(io.dpath.inst, XDecode.decode_default, decode_table)
@ -404,11 +404,11 @@ class Control(implicit conf: RocketConfiguration) extends Module
(x.map(_._1).reduce(_||_), PriorityMux(x))
val fp_csrs = CSRs.fcsr :: CSRs.frm :: CSRs.fflags :: Nil
val legal_csrs = if (conf.fpu) CSRs.all.toSet else CSRs.all.toSet -- fp_csrs
val legal_csrs = if (!conf.fpu.isEmpty) CSRs.all.toSet else CSRs.all.toSet -- fp_csrs
val id_csr_addr = io.dpath.inst(31,20)
val id_csr_en = id_csr != CSR.N
val id_csr_fp = Bool(conf.fpu) && id_csr_en && DecodeLogic(id_csr_addr, fp_csrs, CSRs.all.toSet -- fp_csrs)
val id_csr_fp = Bool(!conf.fpu.isEmpty) && id_csr_en && DecodeLogic(id_csr_addr, fp_csrs, CSRs.all.toSet -- fp_csrs)
val id_csr_wen = id_raddr1 != UInt(0) || !Vec(CSR.S, CSR.C).contains(id_csr)
val id_csr_invalid = id_csr_en && !Vec(legal_csrs.map(UInt(_))).contains(id_csr_addr)
val id_csr_privileged = id_csr_en &&
@ -604,7 +604,7 @@ class Control(implicit conf: RocketConfiguration) extends Module
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.ll_wen, io.dpath.ll_waddr)
val id_stall_fpu = if (conf.fpu) {
val id_stall_fpu = if (!conf.fpu.isEmpty) {
val fp_sboard = new Scoreboard(32)
fp_sboard.set((wb_dcache_miss && wb_reg_fp_wen || io.fpu.sboard_set) && !replay_wb, io.dpath.wb_waddr)
fp_sboard.clear(io.dpath.fp_sboard_clr, io.dpath.fp_sboard_clra)

8
rocket/src/main/scala/dpath_util.scala
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@ -214,9 +214,9 @@ class CSRFile(implicit conf: RocketConfiguration) extends Module
val read_ptbr = reg_ptbr(PADDR_BITS-1,PGIDX_BITS) << PGIDX_BITS
val read_mapping = collection.mutable.Map[Int,Bits](
CSRs.fflags -> (if (conf.fpu) reg_fflags else UInt(0)),
CSRs.frm -> (if (conf.fpu) reg_frm else UInt(0)),
CSRs.fcsr -> (if (conf.fpu) Cat(reg_frm, reg_fflags) else UInt(0)),
CSRs.fflags -> (if (!conf.fpu.isEmpty) reg_fflags else UInt(0)),
CSRs.frm -> (if (!conf.fpu.isEmpty) reg_frm else UInt(0)),
CSRs.fcsr -> (if (!conf.fpu.isEmpty) Cat(reg_frm, reg_fflags) else UInt(0)),
CSRs.cycle -> reg_time,
CSRs.time -> reg_time,
CSRs.instret -> reg_instret,
@ -258,7 +258,7 @@ class CSRFile(implicit conf: RocketConfiguration) extends Module
reg_status.zero := 0
if (!conf.vm) reg_status.vm := false
if (conf.rocc.isEmpty) reg_status.er := false
if (!conf.fpu) reg_status.ef := false
if (conf.fpu.isEmpty) reg_status.ef := false
}
when (decoded_addr(CSRs.fflags)) { reg_fflags := wdata }
when (decoded_addr(CSRs.frm)) { reg_frm := wdata }

8
rocket/src/main/scala/fpu.scala
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@ -6,6 +6,8 @@ import Util._
import FPConstants._
import uncore.constants.MemoryOpConstants._
case class FPUConfig(sfmaLatency: Int = 2, dfmaLatency: Int = 3)
object FPConstants
{
val FCMD_ADD = Bits("b000000")
@ -432,7 +434,7 @@ class FPUDFMAPipe(val latency: Int) extends Module
io.exc := Pipe(valid, fma.io.exceptionFlags, latency-1).bits
}
class FPU(sfma_latency: Int, dfma_latency: Int) extends Module
class FPU(conf: FPUConfig) extends Module
{
val io = new Bundle {
val ctrl = (new CtrlFPUIO).flip
@ -501,7 +503,7 @@ class FPU(sfma_latency: Int, dfma_latency: Int) extends Module
val cmd_fma = mem_ctrl.cmd === FCMD_MADD || mem_ctrl.cmd === FCMD_MSUB ||
mem_ctrl.cmd === FCMD_NMADD || mem_ctrl.cmd === FCMD_NMSUB
val cmd_addsub = mem_ctrl.cmd === FCMD_ADD || mem_ctrl.cmd === FCMD_SUB
val sfma = Module(new FPUSFMAPipe(sfma_latency))
val sfma = Module(new FPUSFMAPipe(conf.sfmaLatency))
sfma.io.valid := io.sfma.valid || ex_reg_valid && ctrl.fma && ctrl.single
sfma.io.in1 := Mux(io.sfma.valid, io.sfma.in1, ex_rs1)
sfma.io.in2 := Mux(io.sfma.valid, io.sfma.in2, ex_rs2)
@ -511,7 +513,7 @@ class FPU(sfma_latency: Int, dfma_latency: Int) extends Module
io.sfma.out := sfma.io.out
io.sfma.exc := sfma.io.exc
val dfma = Module(new FPUDFMAPipe(dfma_latency))
val dfma = Module(new FPUDFMAPipe(conf.dfmaLatency))
dfma.io.valid := io.dfma.valid || ex_reg_valid && ctrl.fma && !ctrl.single
dfma.io.in1 := Mux(io.dfma.valid, io.dfma.in1, ex_rs1)
dfma.io.in2 := Mux(io.dfma.valid, io.dfma.in2, ex_rs2)

3
rocket/src/main/scala/tile.scala
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@ -6,7 +6,8 @@ import Util._
case class RocketConfiguration(tl: TileLinkConfiguration,
icache: ICacheConfig, dcache: DCacheConfig,
fpu: Boolean, rocc: Option[RocketConfiguration => RoCC] = None,
fpu: Option[FPUConfig] = None,
rocc: Option[RocketConfiguration => RoCC] = None,
retireWidth: Int = 1,
vm: Boolean = true,
fastLoadWord: Boolean = true,