PTO-BLOCK-MODEL-LIFECYCLE-LIFETIME

1// PTO-UNIT: {"id":"PTO-BLOCK-MODEL-LIFECYCLE-LIFETIME","surface":"block","classification":["model","lifecycle","lifetime"],"depends_on":["PTO-BLOCK-MODEL-LIFECYCLE-ENTER-STOP"]}2func SaveExecutionContextState(base_address: Word, length_bytes: Word,3                               kind: Word)4begin5    let ring = CurrentACR();6    SaveTrapContext(ring, ring);7    _LastMemoryCommandAddress = base_address;8    _LastMemoryCommandSize = length_bytes;9    _ControlRequestOperand = kind;10end;11
12func RecoverExecutionContextState(base_address: Word, length_bytes: Word,13                                  kind: Word)14begin15    let ring = CurrentACR();16    if !RecoverTrapContext(ring) then17        SetFault(Fault_BundleControl, ReadTPC());18    else19        _LastMemoryCommandAddress = base_address;20        _LastMemoryCommandSize = length_bytes;21        _ControlRequestOperand = kind;22    end;23end;24
25constant PTO_FRAME_SP_INDEX = 2;26constant PTO_FRAME_RA_INDEX = 10;27
28pure func FrameRegisterEndpointLegal(selector: Reg5Selector) => boolean29begin30    return selector >= 2 && selector <= 23;31end;32
33pure func FrameRegisterRangeCount(begin_reg: Reg5Selector,34                                  end_reg: Reg5Selector)35                                  => FrameRegisterCount36begin37    assert FrameRegisterEndpointLegal(begin_reg);38    assert FrameRegisterEndpointLegal(end_reg);39    if end_reg >= begin_reg then40        return ((end_reg - begin_reg) + 1) as FrameRegisterCount;41    else42        return (((24 - begin_reg) + end_reg) - 1)43            as FrameRegisterCount;44    end;45end;46
47pure func FrameRegisterAt(begin_reg: Reg5Selector,48                          ordinal: FrameRegisterOrdinal) => GPRIndex49begin50    let unwrapped = begin_reg + ordinal;51    let wrapped = if unwrapped <= 23 then unwrapped else unwrapped - 22;52    return wrapped as GPRIndex;53end;54
55pure func FrameSlotAddress(caller_sp: Word,56                           ordinal: FrameRegisterOrdinal) => Word57begin58    let byte_offset = (ordinal + 1) * 8;59    return caller_sp - NaturalToWord(byte_offset as integer {0..262144});60end;61
62pure func FrameTemplateOperandsLegal(kind: FrameTemplateKind,63                                     begin_reg: Reg5Selector,64                                     end_reg: Reg5Selector,65                                     size: Word) => boolean66begin67    if !FrameRegisterEndpointLegal(begin_reg) ||68       !FrameRegisterEndpointLegal(end_reg) then69        return FALSE;70    end;71    if kind == FrameTemplate_ReturnStack &&72       begin_reg != PTO_FRAME_RA_INDEX then73        return FALSE;74    end;75    let count = FrameRegisterRangeCount(begin_reg, end_reg);76    return size[2:0] == Zeros{3} && UInt(size) >= count * 8;77end;78
79func StartFrameTemplate(kind: FrameTemplateKind,80                        begin_reg: Reg5Selector,81                        end_reg: Reg5Selector,82                        size: Word) => boolean83begin84    if !FrameTemplateOperandsLegal(kind, begin_reg, end_reg, size) then85        SetFault(Fault_IllegalInstruction, ReadTPC());86        return FALSE;87    end;88
89    let count = FrameRegisterRangeCount(begin_reg, end_reg);90    let current_sp = ReadGPR(PTO_FRAME_SP_INDEX);91    _FrameTemplate.active = TRUE;92    _FrameTemplate.kind = kind;93    _FrameTemplate.instruction_pc = ReadTPC();94    _FrameTemplate.begin_reg = begin_reg;95    _FrameTemplate.end_reg = end_reg;96    _FrameTemplate.register_count = count;97    _FrameTemplate.frame_size = size;98    _FrameTemplate.caller_sp = if kind == FrameTemplate_Entry then99        current_sp100    else101        current_sp + size;102    _FrameTemplate.stack_adjusted = FALSE;103    _FrameTemplate.progress = 0;104    _FrameTemplate.return_target = if kind == FrameTemplate_ReturnAddress then105        _ReturnAddress106    else107        Zeros{PTO_XLEN};108    _FrameTemplate.return_target_valid =109        kind == FrameTemplate_ReturnAddress;110
111    if _FrameTemplate.return_target_valid &&112       _FrameTemplate.return_target[0] == '1' then113        _FrameTemplate.active = FALSE;114        SetFault(Fault_InstructionPC, _FrameTemplate.return_target);115        return FALSE;116    end;117
118    // FENTRY snapshots every source before the destructive sp update.119    if kind == FrameTemplate_Entry then120        for item = 0 to 21 do121            let ordinal = item as FrameRegisterOrdinal;122            if item < count then123                let register = FrameRegisterAt(begin_reg, ordinal);124                _FrameTemplate.source_values[[ordinal]] = ReadGPR(register);125            else126                _FrameTemplate.source_values[[ordinal]] = Zeros{PTO_XLEN};127            end;128        end;129    end;130    return TRUE;131end;132
133func AdjustFrameStackPointer()134begin135    if _FrameTemplate.kind == FrameTemplate_Entry then136        WriteGPR(137            PTO_FRAME_SP_INDEX,138            _FrameTemplate.caller_sp - _FrameTemplate.frame_size);139    else140        WriteGPR(PTO_FRAME_SP_INDEX, _FrameTemplate.caller_sp);141    end;142    _FrameTemplate.stack_adjusted = TRUE;143end;144
145func ExecuteFrameStoreStep()146begin147    assert _FrameTemplate.progress < _FrameTemplate.register_count;148    let ordinal = _FrameTemplate.progress as FrameRegisterOrdinal;149    let address = FrameSlotAddress(_FrameTemplate.caller_sp, ordinal);150    let write_probe = ProbeDataAccess(address, 8, 8, TRUE);151    if RaiseDataAccessFault(write_probe, address) then152        return;153    end;154
155    let value = _FrameTemplate.source_values[[ordinal]];156    StoreTranslated(address, write_probe.translated_address, 8, value);157    RecordStoreEvent(158        write_probe.translated_address,159        8,160        value,161        MemoryOrder_Relaxed);162    _FrameTemplate.progress = (_FrameTemplate.progress + 1)163        as FrameRegisterCount;164end;165
166func ExecuteFrameLoadStep()167begin168    assert _FrameTemplate.progress < _FrameTemplate.register_count;169    let ordinal = _FrameTemplate.progress as FrameRegisterOrdinal;170    let address = FrameSlotAddress(_FrameTemplate.caller_sp, ordinal);171    let read_probe = ProbeDataAccess(address, 8, 8, FALSE);172    if RaiseDataAccessFault(read_probe, address) then173        return;174    end;175
176    let value = LoadTranslatedUnsigned(read_probe.translated_address, 8);177    let register = FrameRegisterAt(_FrameTemplate.begin_reg, ordinal);178    if _FrameTemplate.kind == FrameTemplate_ReturnStack && ordinal == 0 then179        if value[0] == '1' then180            SetFault(Fault_InstructionPC, value);181            return;182        end;183        _FrameTemplate.return_target = value;184        _FrameTemplate.return_target_valid = TRUE;185    end;186
187    RecordLoadEvent(188        read_probe.translated_address,189        8,190        value,191        MemoryOrder_Relaxed);192    WriteGPR(register, value);193    if register == PTO_FRAME_RA_INDEX then194        _ReturnAddress = value;195    end;196    _FrameTemplate.progress = (_FrameTemplate.progress + 1)197        as FrameRegisterCount;198end;199
200func CompleteFrameTemplate()201begin202    let kind = _FrameTemplate.kind;203    _LastFrameBegin = _FrameTemplate.begin_reg;204    _LastFrameEnd = _FrameTemplate.end_reg;205    _LastFrameSize = _FrameTemplate.frame_size;206    _FrameTemplate.active = FALSE;207
208    if kind == FrameTemplate_Entry then209        if _FrameDepth != PTO_MODEL_MEMORY_EVENTS then210            _FrameDepth = (_FrameDepth + 1)211                as integer {0..PTO_MODEL_MEMORY_EVENTS};212        end;213    else214        if _FrameDepth != 0 then215            _FrameDepth = (_FrameDepth - 1)216                as integer {0..PTO_MODEL_MEMORY_EVENTS};217        end;218        if kind == FrameTemplate_ReturnAddress ||219           kind == FrameTemplate_ReturnStack then220            assert _FrameTemplate.return_target_valid;221            WriteTPC(_FrameTemplate.return_target);222        end;223    end;224end;225
226func ExecuteFrameTemplate(kind: FrameTemplateKind,227                          begin_reg: Reg5Selector,228                          end_reg: Reg5Selector,229                          size: Word)230begin231    if !_FrameTemplate.active then232        if !StartFrameTemplate(kind, begin_reg, end_reg, size) then233            return;234        end;235    end;236
237    if _FrameTemplate.instruction_pc != ReadTPC() ||238       _FrameTemplate.kind != kind then239        SetFault(Fault_IllegalInstruction, ReadTPC());240        return;241    end;242
243    if !_FrameTemplate.stack_adjusted then244        AdjustFrameStackPointer();245    end;246    for step = 0 to 21 looplimit 22 do247        if _FrameTemplate.active &&248           _LastFault == Fault_None &&249           _FrameTemplate.progress < _FrameTemplate.register_count then250            if kind == FrameTemplate_Entry then251                ExecuteFrameStoreStep();252            else253                ExecuteFrameLoadStep();254            end;255        end;256    end;257    if _FrameTemplate.active &&258       _LastFault == Fault_None &&259       _FrameTemplate.progress == _FrameTemplate.register_count then260        CompleteFrameTemplate();261    end;262end;263
264func EnterFrame(begin_reg: Reg5Selector,265                end_reg: Reg5Selector,266                size: Word)267begin268    ExecuteFrameTemplate(FrameTemplate_Entry, begin_reg, end_reg, size);269end;270
271func ExitFrame(begin_reg: Reg5Selector,272               end_reg: Reg5Selector,273               size: Word)274begin275    ExecuteFrameTemplate(FrameTemplate_Exit, begin_reg, end_reg, size);276end;277
278func ReturnFromFrame(begin_reg: Reg5Selector,279                     end_reg: Reg5Selector,280                     size: Word,281                     use_return_address: boolean)282begin283    let kind = if use_return_address then284        FrameTemplate_ReturnAddress285    else286        FrameTemplate_ReturnStack;287    ExecuteFrameTemplate(kind, begin_reg, end_reg, size);288end;289