SB

assembly

[
  "sb SrcD, [SrcL, SrcR<{.sw,.uw,.neg}>]"
]

block

[]

catalog_indices

[
  377
]

catalog_records

[
  {
    "agu": {
      "action": "Store",
      "address_kind": "Register",
      "offset_scale": 0,
      "prefetch_returns_address": false,
      "signed_load": false,
      "size_bytes": 1,
      "update_mode": "None"
    },
    "asm": "sb SrcD, [SrcL, SrcR<{.sw,.uw,.neg}>]",
    "constraints": [],
    "encoding": [
      {
        "index": 0,
        "mask": "0x00007fff",
        "match": "0x00000049",
        "width_bits": 32
      }
    ],
    "encoding_kind": "L32",
    "fields": [
      {
        "name": "SrcD",
        "pieces": [
          {
            "instruction_lsb": 27,
            "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
      }
    ],
    "form_id": "sb_32_43c106ae3749",
    "length_bits": 32,
    "mnemonic": "SB",
    "semantic_family": "AGU",
    "semantic_group": "STA/BASE_REG",
    "semantic_handler": "ExecuteScalarStore",
    "semantic_summary": "SB snapshots its scalar sources, forms its encoded address, and stores one aligned little-endian 1-byte value.",
    "status": "accepted"
  }
]

classification

[
  "agu"
]

contract

{
  "block_composition": [
    "none"
  ],
  "canonical_assembly": [
    "sb SrcD, [SrcL, SrcR<{.sw,.uw,.neg}>]"
  ],
  "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": [
    "sb SrcD, [SrcL, SrcR<{.sw,.uw,.neg}>]"
  ],
  "exceptions": [
    "A fixed-bit mismatch, reserved field value, or unavailable selected T/U source raises Fault_IllegalInstruction before instruction effects.",
    "A misaligned 1-byte address raises Fault_DataAlignment before translation or permission. A later permission or bounded-memory failure raises Fault_DataPage at the original address.",
    "A fault emits no successful memory event, performs no partial memory or destination effect, preserves pending writeback, and leaves TPC at the faulting instruction.",
    "Recovery performs a full reissue: every address, source snapshot, preflight, memory operation, and destination is recomputed with no retained progress."
  ],
  "field_contracts": {},
  "field_zero_meanings": {
    "SrcD": "Encoded zero reads the architectural zero GPR.",
    "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."
  },
  "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.",
    "All four SrcRType values and all shamt values 0..31 are assigned; apply the modifier before the shift.",
    "Each memory address must be aligned to the 1-byte access size; a 1-byte access is the complete transfer unit."
  ],
  "memory_effects": [
    "After complete preflight, perform one little-endian 1-byte store and record one relaxed store event.",
    "A successful overlapping store invalidates the overlapping reservation; a nonoverlapping reservation remains valid."
  ],
  "operands": [
    {
      "field": "SrcD",
      "role": "Reg5 first store-data source"
    },
    {
      "field": "SrcL",
      "role": "Reg5 address-base source"
    },
    {
      "field": "SrcR",
      "role": "Reg5 register-offset source"
    },
    {
      "field": "SrcRType",
      "role": "register-offset transformation selector"
    }
  ],
  "ordering": [
    "Snapshot all explicit and implicit scalar sources before destination or memory effects; duplicate and source/destination aliases observe pre-instruction values.",
    "Complete the relaxed 1-byte memory operation, publish any result or writeback, and then advance TPC."
  ],
  "standalone_opcode": true,
  "state_effects": [
    "Form offset = LSL(Modify(SrcR, SrcRType), 0) and add it modulo 2^PTO_XLEN to the SrcL base.",
    "Snapshot every store-data source before any memory effect or destination publication.",
    "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-SB

mnemonic

SB

summary

SB snapshots its scalar sources, forms its encoded address, and stores one aligned little-endian 1-byte value.

surface

scalar

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