PRF

assembly

[
  "prf [SrcL, SrcR<{.sw,.uw,.neg}><<<shamt>]"
]

block

[]

catalog_indices

[
  370
]

catalog_records

[
  {
    "agu": {
      "action": "Prefetch",
      "address_kind": "Register",
      "offset_scale": 0,
      "prefetch_returns_address": false,
      "signed_load": false,
      "size_bytes": 1,
      "update_mode": "None"
    },
    "asm": "prf [SrcL, SrcR<{.sw,.uw,.neg}><<<shamt>]",
    "constraints": [],
    "encoding": [
      {
        "index": 0,
        "mask": "0x0000707f",
        "match": "0x00007009",
        "width_bits": 32
      }
    ],
    "encoding_kind": "L32",
    "fields": [
      {
        "name": "RegDst",
        "pieces": [
          {
            "instruction_lsb": 7,
            "value_lsb": 0,
            "width": 5
          }
        ],
        "signedness": "encoding-defined",
        "width": 5
      },
      {
        "name": "SrcL",
        "pieces": [
          {
            "instruction_lsb": 15,
            "value_lsb": 0,
            "width": 5
          }
        ],
        "signedness": "encoding-defined",
        "width": 5
      },
      {
        "name": "SrcR",
        "pieces": [
          {
            "instruction_lsb": 20,
            "value_lsb": 0,
            "width": 5
          }
        ],
        "signedness": "encoding-defined",
        "width": 5
      },
      {
        "name": "SrcRType",
        "pieces": [
          {
            "instruction_lsb": 25,
            "value_lsb": 0,
            "width": 2
          }
        ],
        "signedness": "encoding-defined",
        "width": 2
      },
      {
        "name": "shamt",
        "pieces": [
          {
            "instruction_lsb": 27,
            "value_lsb": 0,
            "width": 5
          }
        ],
        "signedness": "encoding-defined",
        "width": 5
      }
    ],
    "form_id": "prf_32_30e6dfe4e3ce",
    "length_bits": 32,
    "mnemonic": "PRF",
    "semantic_family": "AGU",
    "semantic_group": "LDA/BASE_REG",
    "semantic_handler": "ScalarPrefetch",
    "semantic_summary": "PRF snapshots its scalar sources, forms its encoded address, and issues a non-binding 1-byte-granularity prefetch hint with no destination effect.",
    "status": "accepted"
  }
]

classification

[
  "agu"
]

contract

{
  "block_composition": [
    "none"
  ],
  "canonical_assembly": [
    "prf [SrcL, SrcR<{.sw,.uw,.neg}><<<shamt>]"
  ],
  "defaults": [
    "Every displayed operand field is encoded explicitly; encoded zero is a value and never denotes omission.",
    "SrcRType=0 leaves SrcR unchanged, SrcRType=1 sign-extends SrcR[31:0], SrcRType=2 zero-extends SrcR[31:0], and SrcRType=3 negates the full PTO_XLEN value. Encoded shamt zero performs no shift."
  ],
  "encoding_class": "standalone-encoded",
  "examples": [
    "prf [SrcL, SrcR<{.sw,.uw,.neg}><<<shamt>]"
  ],
  "exceptions": [
    "A fixed-bit mismatch, reserved field value, or unavailable selected T/U source raises Fault_IllegalInstruction before instruction effects.",
    "A legal prefetch model cannot raise a data-access fault. A reserved model rejects before source reads and before optional address publication."
  ],
  "field_contracts": {},
  "field_zero_meanings": {
    "RegDst": "Encoded zero is the canonical ignored alias value and names no destination.",
    "SrcL": "Encoded zero reads the architectural zero GPR.",
    "SrcR": "Encoded zero reads the architectural zero GPR.",
    "SrcRType": "Encoded zero leaves the complete PTO_XLEN register-offset value unchanged.",
    "shamt": "Encoded zero performs no shift."
  },
  "legality": [
    "Every encoded Reg5 source uses the complete domain: codes 0..23 select absolute GPRs, codes 24..27 select T#1..T#4, and codes 28..31 select U#1..U#4 without consumption.",
    "Every encoded RegDst value is an assigned non-writing alias. Canonical assembly uses zero and does not expose a destination.",
    "All four SrcRType values and all shamt values 0..31 are assigned; apply the modifier before the shift."
  ],
  "memory_effects": [
    "The 1-byte-granularity hint performs no architectural translation, permission or alignment check, memory access, memory event, reservation update, ordering edge, or cache-placement guarantee."
  ],
  "operands": [
    {
      "field": "RegDst",
      "role": "ignored encoded alias field"
    },
    {
      "field": "SrcL",
      "role": "Reg5 address-base source"
    },
    {
      "field": "SrcR",
      "role": "Reg5 register-offset source"
    },
    {
      "field": "SrcRType",
      "role": "register-offset transformation selector"
    },
    {
      "field": "shamt",
      "role": "post-transformation logical-left-shift amount"
    }
  ],
  "ordering": [
    "Snapshot all explicit and implicit scalar sources before destination or memory effects; duplicate and source/destination aliases observe pre-instruction values.",
    "For a legal model, form the hint, publish the optional address result, and then advance TPC by 4 bytes."
  ],
  "standalone_opcode": true,
  "state_effects": [
    "Form offset = LSL(Modify(SrcR, SrcRType), the encoded shamt) and add it modulo 2^PTO_XLEN to the SrcL base.",
    "Discard the formed address after issuing the non-binding hint; no encoded field publishes a result.",
    "Successful execution advances TPC by 4 bytes; a rejected or faulting attempt does not retire."
  ]
}

depends_on

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

id

PTO-SCALAR-PRF

mnemonic

PRF

summary

PRF snapshots its scalar sources, forms its encoded address, and issues a non-binding 1-byte-granularity prefetch hint with no destination effect.

surface

scalar

{
  "classification": [
    "agu"
  ],
  "documentation": "docs/scalar/agu/PRF.md",
  "id": "PTO-SCALAR-PRF",
  "instruction_contract": {
    "artifact": "spec/evidence/instruction-contract-closure.json",
    "mnemonic": "PRF",
    "ndf_clause": "PTO-INST-SCALAR-PRF"
  },
  "mnemonic": "PRF",
  "readiness_subjects": [
    "ADR-0029",
    "ADR-0059",
    "ADR-0084"
  ],
  "semantic_tests": [
    "PTO-AVS-AGU-PRF-ALIAS-001",
    "PTO-AVS-AGU-PRF-BOUND-001",
    "PTO-AVS-AGU-PRF-EXEC-001",
    "PTO-AVS-AGU-PRF-FAULT-001",
    "PTO-AVS-SCALAR-PRF-MODIFIER-001"
  ],
  "source": "asl/scalar/agu/PRF.asl",
  "surface": "scalar",
  "tests": [
    "PTO-AVS-AGU-PRF-ALIAS-001",
    "PTO-AVS-AGU-PRF-BOUND-001",
    "PTO-AVS-AGU-PRF-EXEC-001",
    "PTO-AVS-AGU-PRF-FAULT-001",
    "PTO-AVS-SCALAR-PRF-DECODE-001",
    "PTO-AVS-SCALAR-PRF-MODIFIER-001"
  ]
}