PTO-BLOCK-MODEL-STATE-BARG

1// PTO-UNIT: {"id":"PTO-BLOCK-MODEL-STATE-BARG","surface":"block","classification":["model","state","barg"],"depends_on":["PTO-BLOCK-MODEL-STATE-CONTROL-STATE"]}2// BARG is the sole block-continuation authority. BPC names the current BSTART;3// BlockType identifies the block class; BPCN is the candidate next PC; TYPE4// selects the continuation rule; TAKEN is meaningful only for COND. BARG has5// no TRAP field.6
7// NDF-BEGIN: PTO-BARG-CONTINUATION-0018// ndf: kind=contract level=L1 layer=block status=accepted9// BSTART MUST initialize BARG.BPC, BARG.BlockType, BARG.BPCN, BARG.TYPE, and10// BARG.TAKEN; BSTOP or the next BSTART MUST be the only boundary that selects11// the next PC from BARG.BPCN or the sequential continuation.12// NDF-END: PTO-BARG-CONTINUATION-00113
14readonly func BARGSelectsBPCN() => boolean15begin16    return _BARG.transfer_type == BundleTransfer_Direct ||17           _BARG.transfer_type == BundleTransfer_Call ||18           _BARG.transfer_type == BundleTransfer_Indirect ||19           _BARG.transfer_type == BundleTransfer_IndirectCall ||20           _BARG.transfer_type == BundleTransfer_Return ||21           (_BARG.transfer_type == BundleTransfer_Conditional && _BARG.taken);22end;23
24readonly func BARGCommitPC(continuation: Word) => Word25begin26    if BARGSelectsBPCN() then return _BARG.bpcn;27    else return continuation;28    end;29end;30
31readonly func BARGHasCandidateWord() => boolean32begin33    return _BARG.block_type == BundleKind_Standard ||34           _BARG.block_type == BundleKind_Floating;35end;36
37readonly func PackCurrentBARGControlWord() => Word38begin39    var value: Word = Zeros{PTO_XLEN};40    value[3:0] = PTOv0BundleKindCode(_BARG.block_type);41    if BARGHasCandidateWord() then42        value[6:4] = PTOv0BundleTransferCode(_BARG.transfer_type);43        value[7] = if _BARG.taken then '1' else '0';44    end;45    value[8] = if _BundleControlAttributes.atomic then '1' else '0';46    value[9] = if _BundleControlAttributes.acquire then '1' else '0';47    value[10] = if _BundleControlAttributes.release then '1' else '0';48    value[11] = if _BundleControlAttributes.far then '1' else '0';49    value[12] =50        if _BundleControlAttributes.dimension_reduction then '1' else '0';51    return value;52end;53
54readonly func CurrentBARGWordApplicable(identifier: bits(12)) => boolean55begin56    if !_BundleActive || !_BundleBodyActive then57        return FALSE;58    end;59    case UInt(identifier) of60        when 0 => return TRUE;61        when 1 => return BARGHasCandidateWord();62        when 2 => return TRUE;63        otherwise => return FALSE;64    end;65end;66
67readonly func ReadCurrentBARGWord(identifier: bits(12)) => Word68begin69    assert CurrentBARGWordApplicable(identifier);70    case UInt(identifier) of71        when 0 => return ReadBPC();72        when 1 => return _BARG.bpcn;73        when 2 => return PackCurrentBARGControlWord();74        otherwise => unreachable;75    end;76end;77