func (this *Processor) StartPipelineUnits(config *config.Config, recoveryChannel channel.Channel, operationId, address uint32) func() {
// Initialize channels
addressChannel := channel.New(config.InstructionsFetchedPerCycle()) // Branch Predictor -> Fetch
instructionChannel := channel.New(config.InstructionsQueue()) // Fetch -> Decode
operationChannel := channel.New(config.InstructionsDecodedQueue()) // Decode -> Dispatch
executionChannels := map[info.CategoryEnum]channel.Channel{ // Dispatch -> Execute
info.Aritmetic: channel.New(config.AluUnits()),
info.LoadStore: channel.New(config.LoadStoreUnits()),
info.Control: channel.New(config.BranchUnits()),
info.FloatingPoint: channel.New(config.FpuUnits()),
}
commonDataBusChannel := channel.New(channel.INFINITE) // Execute -> Dispatcher (RS & ROB)
closeUnitsHandlers := []func(){}
/////////////////////////////////////////////////////////////////////////////
// Run stage units in parallel //
// - Units are executed as go routines https://blog.golang.org/pipelines) //
/////////////////////////////////////////////////////////////////////////////
// ---------- Fetch ------------ //
fe := fetcher.New(uint32(0), this, config.InstructionsFetchedPerCycle(), config.BranchPredictorType())
fe.Run(addressChannel, instructionChannel)
closeUnitsHandlers = append(closeUnitsHandlers, fe.Close)
// ---------- Decode ------------ //
for index := uint32(0); index < config.DecoderUnits(); index++ {
de := decoder.New(index, this)
de.Run(instructionChannel, operationChannel)
closeUnitsHandlers = append(closeUnitsHandlers, de.Close)
}
// ----- Dispatch / RS / ROB ---- //
di := dispatcher.New(uint32(0), this, operationId, config.TotalRegisters(),
config.ReservationStationEntries(), config.ReorderBufferEntries(), config.InstructionsDispatchedPerCycle(),
config.InstructionsWrittenPerCycle(), config.RegisterAliasTableEntries())
di.Run(operationChannel, executionChannels, commonDataBusChannel, recoveryChannel)
closeUnitsHandlers = append(closeUnitsHandlers, di.Close)
// ------- Execute (Alu) -------- //
for index := uint32(0); index < config.AluUnits(); index++ {
ex := executor.New(index, this, di.Bus(), info.Aritmetic)
ex.Run(executionChannels, commonDataBusChannel)
closeUnitsHandlers = append(closeUnitsHandlers, ex.Close)
}
// ---- Execute (Load Store) ---- //
for index := uint32(0); index < config.LoadStoreUnits(); index++ {
ex := executor.New(index, this, di.Bus(), info.LoadStore)
ex.Run(executionChannels, commonDataBusChannel)
closeUnitsHandlers = append(closeUnitsHandlers, ex.Close)
}
// ------ Execute (Branch) ------ //
for index := uint32(0); index < config.BranchUnits(); index++ {
ex := executor.New(index, this, di.Bus(), info.Control)
ex.Run(executionChannels, commonDataBusChannel)
closeUnitsHandlers = append(closeUnitsHandlers, ex.Close)
}
// ------- Execute (FPU) -------- //
for index := uint32(0); index < config.FpuUnits(); index++ {
ex := executor.New(index, this, di.Bus(), info.FloatingPoint)
ex.Run(executionChannels, commonDataBusChannel)
closeUnitsHandlers = append(closeUnitsHandlers, ex.Close)
}
// Set instruction for fetching to start pipeline
go addressChannel.Add(operation.New(operationId, address))
// Return flush function for all channels
return func() {
// Close units & channels
for _, closeUnitHandler := range closeUnitsHandlers {
closeUnitHandler()
}
// Close channels
addressChannel.Close()
instructionChannel.Close()
operationChannel.Close()
executionChannels[info.Aritmetic].Close()
executionChannels[info.LoadStore].Close()
executionChannels[info.Control].Close()
executionChannels[info.FloatingPoint].Close()
commonDataBusChannel.Close()
}
}
func (this *Fetcher) fetchInstructions(op *operation.Operation, bytes []byte, input channel.Channel) ([]*operation.Operation, error) {
initialAddress := op.Address()
totalInstructions := len(bytes) / consts.BYTES_PER_WORD
ops := []*operation.Operation{}
// Analyze each instruction loaded
for i := 0; i < totalInstructions; i += 1 {
data := bytes[i*consts.BYTES_PER_WORD : (i+1)*consts.BYTES_PER_WORD]
// Check program reach end
if this.Processor().ReachedEnd(data) {
this.processor.Finish()
return ops, nil
}
// Do fetch once a new address is received
msg := fmt.Sprintf(" => [FE%d][%03d]: INS[%#04X] = %#04X", this.Index(), this.Processor().InstructionsFetchedCounter(), op.Address(), data)
value, ok := this.Processor().InstructionsMap()[op.Address()]
if ok {
msg = fmt.Sprintf("%s // %s", msg, strings.TrimSpace(strings.Split(value, "=>")[1]))
}
logger.Collect(msg)
// Log event
this.Processor().LogInstructionFetched(op.Address())
// Update data into operation and add to array for post-events
op.SetWord([]byte{data[0], data[1], data[2], data[3]})
// Add operation to be sent to decode channel
ops = append(ops, op)
// Do pre-decode
needsWait, instruction := this.BranchPredictor().PreDecodeInstruction(op.Address())
// If is not pipelined than wait instruction to finish
if !this.Processor().Config().Pipelined() {
go func() {
address, _, err := this.BranchPredictor().GetNextAddress(op.Address(), instruction, true)
newOp := operation.New(this.Processor().InstructionsFetchedCounter(), address)
if err == nil {
input.Add(newOp)
}
}()
return ops, nil
}
// Add next instruction for fetching (as many instructions as it supports per cycle)
if needsWait {
logger.Collect(" => [FE%d][%03d]: Wait detected, no fetching more instructions this cycle", this.Index(), this.Processor().InstructionsFetchedCounter()-1)
// Add next instruction in a go routine as it need to be stalled
go func() {
address, _, err := this.BranchPredictor().GetNextAddress(op.Address(), instruction, false)
newOp := operation.New(this.Processor().InstructionsFetchedCounter(), address)
if err == nil {
input.Add(newOp)
}
}()
return ops, nil
} else {
address, predicted, err := this.BranchPredictor().GetNextAddress(op.Address(), instruction, false)
// Set current operation added to be decoded the predicted address
if predicted {
ops[len(ops)-1].SetNextPredictedAddress(address)
}
// Create new operation object
op = operation.New(this.Processor().InstructionsFetchedCounter(), address)
// If is the last instruction from the package or the predicted address is outside of the address package
if err == nil && (i >= totalInstructions-1 || initialAddress+(uint32(i+1)*consts.BYTES_PER_WORD) != op.Address()) {
input.Add(op)
return ops, nil
}
}
}
return ops, nil
}
func (this *ReorderBuffer) Run(commonDataBus channel.Channel, recoveryBus channel.Channel) {
// Launch unit as a goroutine
logger.Print(" => Initializing re-order buffer unit %d", this.Index())
opId := this.StartOperationId()
misprediction := false
clockAllowed := this.Processor().Cycles()
forceClose := false
go func() {
for {
_, running := <-commonDataBus.Channel()
if !running || misprediction {
forceClose = true
logger.Print(" => Flushing re-order buffer unit %d", this.Index())
return
}
commonDataBus.Release()
}
}()
go func() {
for {
if forceClose {
return
}
if this.Processor().Cycles() < clockAllowed {
this.Processor().Wait(1)
continue
}
// Commit in order, if missing an operation, wait for it
computedAddress := uint32(0)
robEntries := []RobEntry{}
for robEntry, exists := this.Buffer()[opId]; exists; robEntry, exists = this.Buffer()[opId] {
if uint32(len(robEntries)) >= this.InstructionsWrittenPerCycle() {
break
}
// Ensure we can write results the next cycle result was written into ROB
if this.Processor().Cycles() > robEntry.Cycle+1 {
// Check for misprediction
misprediction, computedAddress = this.checkForMisprediction(this.Buffer()[opId], robEntries)
// Decrement speculative jumps
this.Processor().DecrementSpeculativeJump()
// Add to queue for commit
robEntries = append(robEntries, robEntry)
opId += 1
// If misprediction, do not process more rob entries
if misprediction {
break
}
}
}
this.commitRobEntries(robEntries)
if misprediction {
this.Processor().Wait(consts.WRITEBACK_CYCLES)
recoveryBus.Add(operation.New(opId, computedAddress))
}
clockAllowed = this.Processor().Cycles() + 1
}
}()
}