BSTART.SYS

assembly

[
  "BSTART.SYS FALL"
]

block

[]

catalog_indices

[
  32
]

catalog_records

[
  {
    "asm": "BSTART.SYS FALL",
    "constraints": [
      {
        "field": "simm17",
        "operator": "one-of",
        "values": [
          0
        ]
      }
    ],
    "encoding": [
      {
        "index": 0,
        "mask": "0x00007fff",
        "match": "0x00001081",
        "width_bits": 32
      }
    ],
    "encoding_kind": "L32",
    "fields": [
      {
        "name": "simm17",
        "pieces": [
          {
            "instruction_lsb": 15,
            "value_lsb": 0,
            "width": 17
          }
        ],
        "signedness": "signed",
        "width": 17
      }
    ],
    "form_id": "bstart_sys_32_762d9d84a6d8",
    "length_bits": 32,
    "mnemonic": "BSTART.SYS",
    "semantic_family": "CMD",
    "semantic_group": "Bundle Split",
    "semantic_handler": "ExecuteBundleStart",
    "semantic_summary": "Closes the current bundle, initializes the next bundle descriptor, and selects its transfer and execution kind.",
    "status": "accepted"
  }
]

classification

[
  "execution"
]

contract

{
  "block_composition": [
    "BSTART.SYS retires any active predecessor block, then opens one system block whose header commands execute sequentially until BSTOP or the next BSTART.",
    "SYS has no candidate transfer: BPCN, TYPE, and TAKEN are inapplicable and cannot select the next PC."
  ],
  "canonical_assembly": [
    "BSTART.SYS FALL"
  ],
  "defaults": [
    "The encoded simm17 field is fixed to zero; nonzero values are extension-reserved."
  ],
  "encoding_class": "standalone-encoded",
  "examples": [
    "BSTART.SYS FALL"
  ],
  "exceptions": [
    "Any nonzero simm17 in the SYS FALL family is extension-reserved and raises before predecessor retirement or new BARG effects.",
    "If predecessor commit fails, the old block and continuation remain authoritative and no system block is installed."
  ],
  "field_contracts": {},
  "field_zero_meanings": {
    "simm17": "Encoded zero supplies a zero displacement or zero immediate value."
  },
  "legality": [
    "Only simm17=0 is accepted; every nonzero payload is extension-reserved."
  ],
  "memory_effects": [
    "none"
  ],
  "operands": [
    {
      "field": "simm17",
      "role": "fixed-zero fallthrough payload; nonzero values are extension-reserved"
    }
  ],
  "ordering": [
    "The fixed-zero payload and form legality are checked before predecessor retirement. New SYS BARG state is installed only after successful retirement."
  ],
  "standalone_opcode": true,
  "state_effects": [
    "On success BPC records the BSTART address and BARG.BlockType becomes SYS. BPCN, TYPE, and TAKEN are inapplicable and are canonicalized to non-selecting values.",
    "Header execution and the eventual block continuation are sequential."
  ]
}

depends_on

[
  "PTO-BLOCK-MODEL-SCHEMA-PROFILE-ENCODING"
]

id

PTO-BLOCK-BSTART-SYS

mnemonic

BSTART.SYS

summary

Closes the current bundle, initializes the next bundle descriptor, and selects its transfer and execution kind.

surface

block

{
  "classification": [
    "execution"
  ],
  "documentation": "docs/block/execution/BSTART.SYS.md",
  "id": "PTO-BLOCK-BSTART-SYS",
  "instruction_contract": {
    "artifact": "spec/evidence/instruction-contract-closure.json",
    "mnemonic": "BSTART.SYS",
    "ndf_clause": "PTO-INST-BLOCK-BSTART-SYS"
  },
  "mnemonic": "BSTART.SYS",
  "readiness_subjects": [
    "ADR-0032",
    "ADR-0052",
    "ADR-0055",
    "ADR-0059",
    "ADR-0077"
  ],
  "semantic_tests": [
    "PTO-AVS-BLOCK-BSTART-SYS-RESERVED-001",
    "PTO-AVS-BLOCK-BSTART-SYS-STATE-001"
  ],
  "source": "asl/block/execution/BSTART.SYS.asl",
  "surface": "block",
  "tests": [
    "PTO-AVS-BLOCK-BSTART-SYS-DECODE-001",
    "PTO-AVS-BLOCK-BSTART-SYS-RESERVED-001",
    "PTO-AVS-BLOCK-BSTART-SYS-STATE-001"
  ]
}