BSTART.STD

assembly

[
  "BSTART.STD COND, <label>",
  "BSTART.STD FALL",
  "BSTART.STD RET",
  "BSTART.STD IND",
  "BSTART.STD DIRECT, <label>"
]

block

[]

catalog_indices

[
  27,
  28,
  29,
  30,
  31
]

catalog_records

[
  {
    "asm": "BSTART.STD COND, <label>",
    "constraints": [],
    "encoding": [
      {
        "index": 0,
        "mask": "0x00007fff",
        "match": "0x00003001",
        "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_std_32_1ef99c4cedcb",
    "length_bits": 32,
    "mnemonic": "BSTART.STD",
    "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"
  },
  {
    "asm": "BSTART.STD FALL",
    "constraints": [
      {
        "field": "simm17",
        "operator": "one-of",
        "values": [
          0
        ]
      }
    ],
    "encoding": [
      {
        "index": 0,
        "mask": "0x00007fff",
        "match": "0x00001001",
        "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_std_32_441ad677fffe",
    "length_bits": 32,
    "mnemonic": "BSTART.STD",
    "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"
  },
  {
    "asm": "BSTART.STD RET",
    "constraints": [],
    "encoding": [
      {
        "index": 0,
        "mask": "0xffffffff",
        "match": "0x00007001",
        "width_bits": 32
      }
    ],
    "encoding_kind": "L32",
    "fields": [],
    "form_id": "bstart_std_32_816dfa76cc4a",
    "length_bits": 32,
    "mnemonic": "BSTART.STD",
    "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"
  },
  {
    "asm": "BSTART.STD IND",
    "constraints": [],
    "encoding": [
      {
        "index": 0,
        "mask": "0xffffffff",
        "match": "0x00005001",
        "width_bits": 32
      }
    ],
    "encoding_kind": "L32",
    "fields": [],
    "form_id": "bstart_std_32_986b7ee2cf6a",
    "length_bits": 32,
    "mnemonic": "BSTART.STD",
    "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"
  },
  {
    "asm": "BSTART.STD DIRECT, <label>",
    "constraints": [],
    "encoding": [
      {
        "index": 0,
        "mask": "0x00007fff",
        "match": "0x00002001",
        "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_std_32_c1de85e06878",
    "length_bits": 32,
    "mnemonic": "BSTART.STD",
    "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.STD retires any active predecessor block, then opens one standard block whose header commands execute sequentially until BSTOP or the next BSTART selects the BARG continuation.",
    "COND publishes a candidate BPCN but SETC may update TAKEN before commit; IND requires and snapshots a retiring Standard or Floating BARG.BPCN, while RET snapshots architectural ra before predecessor retirement."
  ],
  "canonical_assembly": [
    "BSTART.STD COND, <label>",
    "BSTART.STD FALL",
    "BSTART.STD RET",
    "BSTART.STD IND",
    "BSTART.STD DIRECT, <label>"
  ],
  "defaults": [
    "BSTART.STD FALL encodes simm17=0; nonzero values in that family are extension-reserved."
  ],
  "encoding_class": "standalone-encoded",
  "examples": [
    "BSTART.STD FALL",
    "BSTART.STD DIRECT, target",
    "BSTART.STD COND, target",
    "BSTART.STD IND",
    "BSTART.STD RET"
  ],
  "exceptions": [
    "A nonzero FALL simm17, deleted bare CALL/ICALL encoding, reserved BrType, odd target, or unsupported form raises before predecessor retirement or new BARG effects.",
    "IND without an active retiring Standard or Floating BARG raises Fault_BundleControl before effects.",
    "If predecessor commit fails, the old block and continuation remain authoritative and no standard block is installed."
  ],
  "field_contracts": {},
  "field_zero_meanings": {
    "simm17": "Encoded zero supplies a zero displacement or zero immediate value."
  },
  "legality": [
    "Exactly FALL, DIRECT, COND, IND, and RET are accepted.",
    "The FALL form accepts only simm17=0; every nonzero FALL payload is extension-reserved.",
    "Bare CALL and ICALL forms are deleted."
  ],
  "memory_effects": [
    "none"
  ],
  "operands": [
    {
      "field": "simm17",
      "role": "17-bit signed bundle target displacement"
    }
  ],
  "ordering": [
    "All target, descriptor, and form checks precede predecessor retirement. New BARG state is installed only after successful retirement."
  ],
  "standalone_opcode": true,
  "state_effects": [
    "On success BPC records the BSTART address; BARG.BlockType becomes STD; BARG.TYPE records FALL, DIRECT, COND, IND, or RET; BARG.BPCN records the candidate target; and BARG.TAKEN is false only for COND until SETC resolves it.",
    "Header execution continues at the sequential PC. BSTOP or the next BSTART commits the candidate continuation selected by BARG."
  ]
}

depends_on

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

id

PTO-BLOCK-BSTART-STD

mnemonic

BSTART.STD

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