Operands and parameters
RegDst- Reg5 scalar destination or discard selector
SrcL- Reg5 scalar source; only bits 31:0 participate
uimm24- unsigned split 24-bit immediate
HL.SUBIW applies word subtraction to SrcL[31:0] and the low word of a zero-extended 24-bit immediate, then sign-extends the 32-bit result.
PTO-SCALAR-HL-SUBIWhl.subiw SrcL, uimm, ->{t, u, Rd}| Field | Bits | Signedness | Architectural role | Encoded zero |
|---|---|---|---|---|
RegDst | 5 | encoding-defined | Reg5 scalar destination or discard selector | Encoded zero discards the result and does not modify any GPR or queue. |
SrcL | 5 | encoding-defined | Reg5 scalar source; only bits 31:0 participate | Encoded zero reads architectural GPR zero. |
uimm24 | 24 | unsigned | unsigned split 24-bit immediate | Encoded zero supplies numeric zero. |
Loading WaveDrom diagram… The encoding table and WaveJSON remain available below.
| Decoded item | Bit range | Value |
|---|---|---|
| uimm24 | 47:36 | variable |
| SrcL | 35:31 | variable |
| Constant | 30:28 | 3'b001 |
| RegDst | 27:23 | variable |
| Constant | 22:16 | 7'b0110101 |
| uimm24 | 15:4 | variable |
| Constant | 3:0 | 4'b1110 |
{
"reg": [
{
"bits": 4,
"name": "4'b1110"
},
{
"bits": 12,
"name": "uimm24"
},
{
"bits": 7,
"name": "7'b0110101"
},
{
"bits": 5,
"name": "RegDst"
},
{
"bits": 3,
"name": "3'b001"
},
{
"bits": 5,
"name": "SrcL"
},
{
"bits": 12,
"name": "uimm24"
}
],
"config": {
"bits": 48,
"fontsize": 13,
"hspace": 900,
"lanes": 2,
"offset": 0
}
}hl.subiw SrcL, uimm, ->{t, u, Rd}
RegDstSrcLuimm24This Operation comes directly from the instruction owner; the page does not rewrite its behavior.
readonly func InstructionContractOperation_HL_SUBIW() => ScalarOperationbegin return ScalarOperation_HL_SUBIW;end;readonly func InstructionContractHandler_HL_SUBIW() => ScalarSemanticHandlerbegin return ScalarHandler_ScalarBinaryW;end;
pure func InstructionContractImmediateWidth_HL_SUBIW() => integer {1..64}begin return 24;end;
pure func InstructionContractImmediateIsUnsigned_HL_SUBIW() => booleanbegin return TRUE;end;
pure func InstructionContractIsWordOperation_HL_SUBIW() => booleanbegin return TRUE;end;
pure func InstructionContractResult_HL_SUBIW( left: Word, immediate: bits(24)) => Wordbegin let right = ZeroExtend{PTO_XLEN}(immediate); return ScalarBinaryW( ScalarBinary_SUB, left, right);end;// PTO-INSTRUCTION: {"assembly":["hl.subiw SrcL, uimm, ->{t, u, Rd}"],"block":[],"catalog_indices":[286],"catalog_records":[{"asm":"hl.subiw SrcL, uimm, ->{t, u, Rd}","constraints":[],"encoding":[{"index":0,"mask":"0x0000707f000f","match":"0x00001035000e","width_bits":48}],"encoding_kind":"HL48","fields":[{"name":"RegDst","pieces":[{"instruction_lsb":23,"value_lsb":0,"width":5}],"signedness":"encoding-defined","width":5},{"name":"SrcL","pieces":[{"instruction_lsb":31,"value_lsb":0,"width":5}],"signedness":"encoding-defined","width":5},{"name":"uimm24","pieces":[{"instruction_lsb":36,"value_lsb":0,"width":12},{"instruction_lsb":4,"value_lsb":12,"width":12}],"signedness":"unsigned","width":24}],"form_id":"hl_subiw_48_adc7b127a2f8","length_bits":48,"mnemonic":"HL.SUBIW","semantic_family":"ALU","semantic_group":"ALU","semantic_handler":"ScalarBinaryW","semantic_summary":"HL.SUBIW applies word subtraction to SrcL[31:0] and the low word of a zero-extended 24-bit immediate, then sign-extends the 32-bit result.","status":"accepted"}],"classification":["alu"],"contract":{"block_composition":["none"],"canonical_assembly":["hl.subiw SrcL, uimm, ->{t, u, Rd}"],"defaults":["SrcL, uimm24, and RegDst are required encoded fields; no field can be omitted.","uimm24 has the complete unsigned 24-bit range 0 through 16777215; encoded zero is numeric zero."],"encoding_class":"standalone-encoded","examples":["hl.subiw a0, 1, ->a0","hl.subiw t#1, 16777215, ->u","hl.subiw zero, 0, ->zero"],"exceptions":["HL.SUBIW raises no arithmetic exception; fixed-width overflow or underflow is discarded.","A fixed-bit mismatch or unavailable selected T/U source raises Fault_IllegalInstruction before any destination effect and before TPC advances."],"field_contracts":{},"field_zero_meanings":{"RegDst":"Encoded zero discards the result and does not modify any GPR or queue.","SrcL":"Encoded zero reads architectural GPR zero.","uimm24":"Encoded zero supplies numeric zero."},"legality":["All 32 SrcL encodings are assigned: 0..23 select absolute GPRs, 24..27 select T#1..T#4, and 28..31 select U#1..U#4 without consuming a queue entry.","All 32 RegDst encodings are assigned: codes 0 and 24..29 discard, codes 1..23 write absolute GPRs, code 30 pushes U, and code 31 pushes T.","Every unsigned 24-bit value is assigned. The two 12-bit pieces reconstruct one exact 24-bit value."],"memory_effects":["none"],"operands":[{"field":"RegDst","role":"Reg5 scalar destination or discard selector"},{"field":"SrcL","role":"Reg5 scalar source; only bits 31:0 participate"},{"field":"uimm24","role":"unsigned split 24-bit immediate"}],"ordering":["Snapshot SrcL before the destination effect, including GPR aliases and same-queue read-then-push cases.","Publish the result through RegDst, then advance TPC by six bytes."],"standalone_opcode":true,"state_effects":["Take SrcL[31:0] and the low 32 bits of the zero-extended uimm24, compute word subtraction modulo 2^32, sign-extend the 32-bit result to PTO_XLEN, and publish it through RegDst.","Codes 1..23 write a GPR; codes 0 and 24..29 discard; code 30 pushes U; code 31 pushes T. Relative source reads are non-consuming.","No memory, reservation, descriptor, Tile, block, privilege, numeric-status, branch-target, or other control state changes. Successful execution advances TPC by six bytes."]},"depends_on":["PTO-BLOCK-MODEL-SCHEMA-PROFILE-ENCODING"],"id":"PTO-SCALAR-HL-SUBIW","mnemonic":"HL.SUBIW","summary":"HL.SUBIW applies word subtraction to SrcL[31:0] and the low word of a zero-extended 24-bit immediate, then sign-extends the 32-bit result.","surface":"scalar"}// PTO-REVIEW: {"review_method":"formal-definition-read","outcome":"FORMAL-COMPLETE","reviewed_fields":["assembly","encoding","defaults","operation","state","memory","ordering","faults","reserved"]}// NDF-BEGIN: PTO-HL-SUBIW-CONTRACT-001// ndf: kind=contract level=L1 layer=scalar status=accepted// HL.SUBIW MUST reconstruct its split uimm24 field exactly and apply// word subtraction with a zero-extended unsigned 24-bit immediate.// Only the low 32 bits of both operands participate; the 32-bit result MUST be sign-extended to PTO_XLEN.// SrcL MUST use the complete non-consuming Reg5 source map. RegDst MUST// use the common GPR, discard, U-push, and T-push destination map.// The source MUST be snapshotted before destination publication.// Successful execution MUST advance TPC by six bytes and MUST NOT change// memory, Tile, block, reservation, privilege, numeric-status, or fault state.// NDF-END: PTO-HL-SUBIW-CONTRACT-001// DOC-BEGIN: decodereadonly func InstructionContractOperation_HL_SUBIW() => ScalarOperationbegin return ScalarOperation_HL_SUBIW;end;// DOC-END: decode// DOC-BEGIN: operationreadonly func InstructionContractHandler_HL_SUBIW() => ScalarSemanticHandlerbegin return ScalarHandler_ScalarBinaryW;end;
pure func InstructionContractImmediateWidth_HL_SUBIW() => integer {1..64}begin return 24;end;
pure func InstructionContractImmediateIsUnsigned_HL_SUBIW() => booleanbegin return TRUE;end;
pure func InstructionContractIsWordOperation_HL_SUBIW() => booleanbegin return TRUE;end;
pure func InstructionContractResult_HL_SUBIW( left: Word, immediate: bits(24)) => Wordbegin let right = ZeroExtend{PTO_XLEN}(immediate); return ScalarBinaryW( ScalarBinary_SUB, left, right);end;// DOC-END: operation
HL.SUBIW is a 48-bit scalar ALU instruction. It performs subtraction under the low 32-bit word, followed by sign-extension to XLEN result rules; its current instruction contract defines the result publication path and any additional state effect.
Execution snapshots the encoded inputs, then performs subtraction under the low 32-bit word, followed by sign-extension to XLEN result rules, and only afterward performs the destination effects.
RegDst field selects the Reg5 scalar result target or discards the result.SrcL field selects a Reg5 scalar value whose low 32 bits participate.uimm24 field carries the unsigned split 24-bit immediate.These roles come from the current instruction contract. T/U sources are read and snapshotted without being removed from their queues; exact encoded-zero meanings appear in the generated defaults below.
Every scalar source is snapshotted before the destination effect. The completed value is then routed through RegDst using the current scalar destination map.
This ALU operation has no memory effect. After its successful architectural effects, TPC advances by 6 bytes.
The operation does not introduce a hidden scalar publication target or an implicit memory access. Architectural changes remain limited to the state effects enumerated by the current contract.
Fixed-width arithmetic follows the operation’s wraparound rule without an arithmetic exception. A fixed-bit mismatch or unavailable selected T/U source raises Fault_IllegalInstruction before publication and before TPC advances.
The generated legality table is authoritative for assigned field values, reserved encodings, and destination discard codes. Decode and source availability are checked before architectural effects.
This example illustrates the current ASL owner and does not replace the normative operation.
For a small HL.SUBIW example, SrcL=7 and uimm24=3 produce 4.
Bodies come from owning ASL. Dragging or buttons change only this page-session view order.
HL.SUBIW MUST reconstruct its split uimm24 field exactly and apply word subtraction with a zero-extended unsigned 24-bit immediate. Only the low 32 bits of both operands participate; the 32-bit result MUST be sign-extended to PTO_XLEN. SrcL MUST use the complete non-consuming Reg5 source map. RegDst MUST use the common GPR, discard, U-push, and T-push destination map. The source MUST be snapshotted before destination publication. Successful execution MUST advance TPC by six bytes and MUST NOT change memory, Tile, block, reservation, privilege, numeric-status, or fault state.
PTO-HL-SUBIW-CONTRACT-001asl/scalar/alu/HL.SUBIW.asle2ae3a6a032891f01c4ccfef7861ae9d0b04d008a530e8dd711f2725826d251e5bde339ab65b04d2ff3c99f1ef09ed9978cb2dec30e428b225f1177c25797fda12 matching entries
PTO-AVS-SCALAR-HL-SUBIW-DECODE-001tests/asl/scalar/alu/HL.SUBIW/scalar-decode-hl-subiw-canonical-001.asl66c1d2670931bba4bda88e771232c3f575c119f4192ba6692a23f4a4caf9fa63PTO-AVS-SCALAR-HL-SUBIW-READINESS-001tests/asl/scalar/alu/HL.SUBIW/scalar-fault-hl-subiw-readiness-001.asl5eaad7ff790eaa82cbbc2c5c339c9ca38b7060320152f653145f47b58d9d68dcPTO-AVS-SCALAR-HL-SUBIW-RESULT-001tests/asl/scalar/alu/HL.SUBIW/scalar-exec-hl-subiw-result-001.aslaeb63e9f31f9134eee2d60a3ea7691ca5bb9190c2599d549f6c3fe314548af0aPTO-AVS-SCALAR-HL-SUBIW-SELECTORS-001tests/asl/scalar/alu/HL.SUBIW/scalar-bound-hl-subiw-selectors-001.asleb7794f87fae6daf7f8a30316217f52418344d1196475bfd889063a4026af5dePTO-EVIDENCE-RELEASE-TRACEABILITYPTO-EVIDENCE-RELEASE-TRACEABILITYspec/evidence/release-traceability-readiness.jsonc7327021d39dc67ac5564bc55073b3870a397d79ac8d9648284d56e33bc14a3ePTO-EVIDENCE-INSTRUCTION-CONTRACT-CLOSUREPTO-EVIDENCE-INSTRUCTION-CONTRACT-CLOSUREspec/evidence/instruction-contract-closure.json3ef2bb62421c79dff8fa77a1c7983923b523244b8090812883ef81286ca8106aPTO-EVIDENCE-ARCHITECTURE-READINESSPTO-EVIDENCE-ARCHITECTURE-READINESSspec/evidence/architecture-readiness.json4b0b85199101251bea744e0f3591cc31906909dc80d5ab651c417a936036a004PTO-EVIDENCE-RELEASE-GATE-READINESSPTO-EVIDENCE-RELEASE-GATE-READINESSspec/evidence/release-gate-readiness.jsona0f4d2b6920c08981ea55fd8ef820708a40d4feb5402c5150e8e9ab532d84ce0PTO-EVIDENCE-RELEASE-MANIFESTPTO-EVIDENCE-RELEASE-MANIFESTspec/release-manifest.json1a64c109ed7a90351c41e2a418b3c0ebaf8ad975838986d2101385186b85c0d8Loading ADR-0026…
ADR-0026docs/status/decisions/0026-scalar-alu-totality-and-alias-order.md41d126f224dddc371832120f1b02eab64e426872fdcbea452bad77c90bdec349Loading ADR-0059…
ADR-0059docs/status/decisions/0059-mnemonic-field-encoding-closure.mdf18d13f735cfaf9f2803c754c5818f4af33d1cc42c489f0d9ce060b07bb3a196Loading ADR-0084…
ADR-0084docs/status/decisions/0084-scalar-system-and-queue-operations.mde068992fa81e2c4ac46e492391a2f784141d68e041bf0b9e0586c37217d1e08c{
"classification": [
"alu"
],
"documentation": "docs/scalar/alu/HL.SUBIW.md",
"id": "PTO-SCALAR-HL-SUBIW",
"instruction_contract": {
"artifact": "spec/evidence/instruction-contract-closure.json",
"mnemonic": "HL.SUBIW",
"ndf_clause": "PTO-INST-SCALAR-HL-SUBIW"
},
"mnemonic": "HL.SUBIW",
"readiness_subjects": [
"ADR-0026",
"ADR-0059",
"ADR-0084"
],
"semantic_tests": [
"PTO-AVS-SCALAR-HL-SUBIW-READINESS-001",
"PTO-AVS-SCALAR-HL-SUBIW-RESULT-001",
"PTO-AVS-SCALAR-HL-SUBIW-SELECTORS-001"
],
"source": "asl/scalar/alu/HL.SUBIW.asl",
"surface": "scalar",
"tests": [
"PTO-AVS-SCALAR-HL-SUBIW-DECODE-001",
"PTO-AVS-SCALAR-HL-SUBIW-READINESS-001",
"PTO-AVS-SCALAR-HL-SUBIW-RESULT-001",
"PTO-AVS-SCALAR-HL-SUBIW-SELECTORS-001"
]
}0.58.5 · Release candidate7dc8b7e5b121d2b2499a2273bebff29e2cd86812e2ae3a6a032891f01c4ccfef7861ae9d0b04d008a530e8dd711f2725826d251e756cf81c0cfb0820eab13aff571bacd026e0c391d39a8b84b5bee93f7164c629asl/scalar/alu/HL.SUBIW.aslasl/scalar/alu/HL.SUBIW.aslasl/scalar/alu/HL.SUBIW.asl