Operands and parameters
RegDst- Reg5 destination or discard
SrcL- left or sole Reg5 source
SrcR- right Reg5 source
SrcType- source carrier selector
FLTS performs ordered signaling less-than comparison and returns canonical XLEN zero or one.
PTO-SCALAR-FLTSflts.{T} SrcL, SrcR, ->{t, u, Rd}| Field | Bits | Signedness | Architectural role | Encoded zero |
|---|---|---|---|---|
RegDst | 5 | encoding-defined | Reg5 destination or discard | Encoded zero discards the result. |
SrcL | 5 | encoding-defined | left or sole Reg5 source | Encoded zero reads the architectural zero GPR. |
SrcR | 5 | encoding-defined | right Reg5 source | Encoded zero reads the architectural zero GPR. |
SrcType | 2 | encoding-defined | source carrier selector | Encoded zero selects the 64-bit source carrier; it is not omission. |
Loading WaveDrom diagram… The encoding table and WaveJSON remain available below.
| Decoded item | Bit range | Value |
|---|---|---|
| Constant | 31:27 | 5'b00001 |
| SrcType | 26:25 | variable |
| SrcR | 24:20 | variable |
| SrcL | 19:15 | variable |
| Constant | 14:12 | 3'b010 |
| RegDst | 11:7 | variable |
| Constant | 6:0 | 7'b1011011 |
{
"reg": [
{
"bits": 7,
"name": "7'b1011011"
},
{
"bits": 5,
"name": "RegDst"
},
{
"bits": 3,
"name": "3'b010"
},
{
"bits": 5,
"name": "SrcL"
},
{
"bits": 5,
"name": "SrcR"
},
{
"bits": 2,
"name": "SrcType"
},
{
"bits": 5,
"name": "5'b00001"
}
],
"config": {
"bits": 32,
"fontsize": 13,
"hspace": 900,
"lanes": 1,
"offset": 0
}
}flts.{T} SrcL, SrcR, ->{t, u, Rd}
RegDstSrcLSrcRSrcTypeThis Operation comes directly from the instruction owner; the page does not rewrite its behavior.
readonly func InstructionContractOperation_FLTS() => ScalarOperationbegin return ScalarOperation_FLTS;end;readonly func InstructionContractHandler_FLTS() => ScalarSemanticHandlerbegin return ScalarHandler_FloatingCompare;end;
pure func InstructionContractSourceTypeLegal_FLTS(encoded: bits(2)) => booleanbegin return encoded == '00' || encoded == '01';end;
pure func InstructionContractSourceCarrier_FLTS(encoded: bits(2)) => bits(5)begin assert InstructionContractSourceTypeLegal_FLTS(encoded); return ScalarFPSourceTypeCode(encoded);end;
pure func InstructionContractSourceArity_FLTS() => integer {1..3}begin return 2;end;
pure func InstructionContractUsesProfileFlags_FLTS() => booleanbegin return FALSE;end;
pure func InstructionContractUsesActiveRounding_FLTS() => booleanbegin return FALSE;end;
pure func InstructionContractCompareOperation_FLTS() => FloatingCompareOperationbegin return FloatingCompare_LT;end;
pure func InstructionContractSignalingCompare_FLTS() => booleanbegin return TRUE;end;// PTO-INSTRUCTION: {"assembly":["flts.{T} SrcL, SrcR, ->{t, u, Rd}"],"block":[],"catalog_indices":[104],"catalog_records":[{"asm":"flts.{T} SrcL, SrcR, ->{t, u, Rd}","constraints":[{"field":"SrcType","operator":"one-of","values":[0,1]}],"encoding":[{"index":0,"mask":"0xf800707f","match":"0x0800205b","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":"SrcType","pieces":[{"instruction_lsb":25,"value_lsb":0,"width":2}],"signedness":"encoding-defined","width":2}],"form_id":"flts_32_c744c874e6a2","length_bits":32,"mnemonic":"FLTS","semantic_family":"FSU","semantic_group":"FSU","semantic_handler":"FloatingCompare","semantic_summary":"FLTS performs ordered signaling less-than comparison and returns canonical XLEN zero or one.","status":"accepted"}],"classification":["fsu"],"contract":{"block_composition":["none"],"canonical_assembly":["flts.{T} SrcL, SrcR, ->{t, u, Rd}"],"defaults":["Every displayed operand field is encoded explicitly; encoded zero is a value and never denotes omission.","SrcType=0 selects an FP64 carrier and SrcType=1 selects the zero-extended low-word FP32 carrier. SrcType=2 and SrcType=3 are reserved."],"encoding_class":"standalone-encoded","examples":["flts.fd a0, a1, ->a2","flts.fs t#1, u#1, ->u"],"exceptions":["A fixed-bit mismatch, reserved SrcType, reserved DstType where present, or unavailable selected T/U source raises Fault_IllegalInstruction before source, profile, destination, flag, queue, or TPC effects.","Numeric profile flags update sticky status and do not themselves raise a synchronous PTO trap."],"field_contracts":{},"field_zero_meanings":{"RegDst":"Encoded zero discards the result.","SrcL":"Encoded zero reads the architectural zero GPR.","SrcR":"Encoded zero reads the architectural zero GPR.","SrcType":"Encoded zero selects the 64-bit source carrier; it is not omission."},"legality":["Every Reg5 source uses codes 0..23 for absolute GPRs, 24..27 for T#1..T#4, and 28..31 for U#1..U#4 without consumption.","Every Reg5 destination is assigned: codes 1..23 write GPRs, 30 pushes U, 31 pushes T, and 0 plus 24..29 discard only the result.","SrcType codes 0 and 1 are assigned; codes 2 and 3 are reserved."],"memory_effects":["none"],"operands":[{"field":"RegDst","role":"Reg5 destination or discard"},{"field":"SrcL","role":"left or sole Reg5 source"},{"field":"SrcR","role":"right Reg5 source"},{"field":"SrcType","role":"source carrier selector"}],"ordering":["Validate every encoded type before the first architectural source read or profile call.","Snapshot every explicit source before flag or destination effects; duplicate sources, destination aliases, and same-queue read-then-push observe pre-instruction values.","Accumulate produced flags, publish or discard the destination, and then advance TPC."],"standalone_opcode":true,"state_effects":["FLTS performs ordered signaling less-than comparison and returns canonical XLEN zero or one.","Any NaN returns false. This signaling form records sticky NV for any NaN.","Destination codes 1..23 write GPRs, 30 pushes U, 31 pushes T, and 0 plus 24..29 discard the result.","Successful execution advances TPC by four bytes."]},"depends_on":["PTO-SCALAR-MODEL-FSU-PROFILE"],"id":"PTO-SCALAR-FLTS","mnemonic":"FLTS","summary":"FLTS performs ordered signaling less-than comparison and returns canonical XLEN zero or one.","surface":"scalar"}// PTO-REVIEW: {"review_method":"formal-definition-read","outcome":"FORMAL-COMPLETE","reviewed_fields":["assembly","encoding","defaults","operation","state","memory","ordering","faults","reserved"]}// DOC-BEGIN: decodereadonly func InstructionContractOperation_FLTS() => ScalarOperationbegin return ScalarOperation_FLTS;end;// DOC-END: decode// DOC-BEGIN: operationreadonly func InstructionContractHandler_FLTS() => ScalarSemanticHandlerbegin return ScalarHandler_FloatingCompare;end;
pure func InstructionContractSourceTypeLegal_FLTS(encoded: bits(2)) => booleanbegin return encoded == '00' || encoded == '01';end;
pure func InstructionContractSourceCarrier_FLTS(encoded: bits(2)) => bits(5)begin assert InstructionContractSourceTypeLegal_FLTS(encoded); return ScalarFPSourceTypeCode(encoded);end;
pure func InstructionContractSourceArity_FLTS() => integer {1..3}begin return 2;end;
pure func InstructionContractUsesProfileFlags_FLTS() => booleanbegin return FALSE;end;
pure func InstructionContractUsesActiveRounding_FLTS() => booleanbegin return FALSE;end;
pure func InstructionContractCompareOperation_FLTS() => FloatingCompareOperationbegin return FloatingCompare_LT;end;
pure func InstructionContractSignalingCompare_FLTS() => booleanbegin return TRUE;end;// DOC-END: operation
FLTS performs ordered signaling less-than and publishes canonical XLEN one or zero.
SrcType=00 selects a complete FP64 carrier; SrcType=01 selects the zero-extended low 32-bit FP32 carrier.
Any NaN input makes the ordered comparison false.
The signaling form records sticky NV for any NaN.
RegDst selects the encoded destination or discard behavior.SrcL supplies the left scalar source.SrcR supplies the right scalar source.SrcType selects the source-carrier width.All explicit sources are snapshotted before numeric-status or destination effects.
Any architecture-produced NV is ORed into sticky numeric state before destination publication.
The result is published or discarded, then TPC advances by 4 bytes. The instruction has no memory or reservation effect.
SrcType=10 and SrcType=11 are reserved. Reserved types and unavailable T/U sources raise Fault_IllegalInstruction before source, profile, flag, queue, destination, or TPC effects.
Numeric flag updates do not themselves raise a synchronous PTO trap.
This example illustrates the current owner and does not define arithmetic independently of the normative rule or active profile.
flts.fd a0, a1, ->a2 applies the architecture-owned special-value rule and publishes canonical output before advancing TPC.
Bodies come from owning ASL. Dragging or buttons change only this page-session view order.
No NDF clause is attached to this unit.
17 matching entries
PTO-AVS-FSU-FLTS-BOUND-001tests/asl/scalar/fsu/FLTS/scalar-bound-flts-values-001.asl069ddcd4de3b44f82d71bda050b4478f8d612a6a14f73cbd1fde4503a1e28547PTO-AVS-FSU-FLTS-DST-001tests/asl/scalar/fsu/FLTS/scalar-exec-flts-dst-001.aslddde065c177669026a148ab3a84face1b5b85992aed64bcf6541174f040b0571PTO-AVS-FSU-FLTS-EXEC-001tests/asl/scalar/fsu/FLTS/scalar-exec-flts-direct-001.aslbe14df74eb3acc7fa17798f6bedfadf24aea536bac54709aeeb2a5161c0e8330PTO-AVS-FSU-FLTS-FLAGS-001tests/asl/scalar/fsu/FLTS/scalar-state-flts-flags-001.asle3153b103a091a3ea46c10ee081a2ba7fbaa119380944653a4181a291ef506faPTO-AVS-FSU-FLTS-RSVD-001tests/asl/scalar/fsu/FLTS/scalar-fault-flts-types-001.asl74768cd80a5cf225ddc77e5f3b69660f9945adac8359bb75df280b0f8d34ff70PTO-AVS-FSU-FLTS-SNAP-001tests/asl/scalar/fsu/FLTS/scalar-exec-flts-snap-001.asl32fbd994d2e3243133403ab777b7d7a48f833e7dc9df84b0cd39a39e5dae4196PTO-AVS-FSU-FLTS-SRC-001tests/asl/scalar/fsu/FLTS/scalar-exec-flts-src-001.asle42fe7aee3e8ad99c5fa5a288d21eac36050ffd094b442712530a8382226e49aPTO-AVS-FSU-FLTS-TYPE-001tests/asl/scalar/fsu/FLTS/scalar-bound-flts-types-001.asla5d52a80b29070bdd339c2a33504f068058745a2ad5e0e071ecd334150634fabPTO-AVS-SCALAR-FLTS-DECODE-001tests/asl/scalar/fsu/FLTS/scalar-decode-flts-canonical-001.asle65e48ab790c3de7ee77e5e9db61f4ced96c2bb02e67b09e33849b5893722fbbPTO-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-0028…
ADR-0028docs/status/decisions/0028-scalar-fsu-totality-and-profile-boundary.md1be39ca1ffda14b703ca03df9654f323d03b9cac620ba37d5cbe6ce8f3f9c486Loading ADR-0038…
ADR-0038docs/status/decisions/0038-scalar-numeric-flag-state-and-ownership.mdeac15c3bee955bb92833482b9af8b9f149fe17c13138e6f2b22f0ed1cf40fc07Loading ADR-0059…
ADR-0059docs/status/decisions/0059-mnemonic-field-encoding-closure.mdf18d13f735cfaf9f2803c754c5818f4af33d1cc42c489f0d9ce060b07bb3a196{
"classification": [
"fsu"
],
"documentation": "docs/scalar/fsu/FLTS.md",
"id": "PTO-SCALAR-FLTS",
"instruction_contract": {
"artifact": "spec/evidence/instruction-contract-closure.json",
"mnemonic": "FLTS",
"ndf_clause": "PTO-INST-SCALAR-FLTS"
},
"mnemonic": "FLTS",
"readiness_subjects": [
"ADR-0028",
"ADR-0038",
"ADR-0059"
],
"semantic_tests": [
"PTO-AVS-FSU-FLTS-BOUND-001",
"PTO-AVS-FSU-FLTS-DST-001",
"PTO-AVS-FSU-FLTS-EXEC-001",
"PTO-AVS-FSU-FLTS-FLAGS-001",
"PTO-AVS-FSU-FLTS-RSVD-001",
"PTO-AVS-FSU-FLTS-SNAP-001",
"PTO-AVS-FSU-FLTS-SRC-001",
"PTO-AVS-FSU-FLTS-TYPE-001"
],
"source": "asl/scalar/fsu/FLTS.asl",
"surface": "scalar",
"tests": [
"PTO-AVS-FSU-FLTS-BOUND-001",
"PTO-AVS-FSU-FLTS-DST-001",
"PTO-AVS-FSU-FLTS-EXEC-001",
"PTO-AVS-FSU-FLTS-FLAGS-001",
"PTO-AVS-FSU-FLTS-RSVD-001",
"PTO-AVS-FSU-FLTS-SNAP-001",
"PTO-AVS-FSU-FLTS-SRC-001",
"PTO-AVS-FSU-FLTS-TYPE-001",
"PTO-AVS-SCALAR-FLTS-DECODE-001"
]
}0.58.5 · Release candidate7dc8b7e5b121d2b2499a2273bebff29e2cd86812ca120d0b4c6d9613a5451f9ba29c651da38487afec78a8856d98d6bbe04c966ac5ff86699c690bb3ae6b6ceb6a041be1974fbac6a33b2e48285cecd61643bca1asl/scalar/fsu/FLTS.aslasl/scalar/fsu/FLTS.asl