PTO-ARCH-DATA-TYPES-FORMAT-E8M0This Operation comes directly from the instruction owner; the page does not rewrite its behavior.
// PTO-REQ-HARDWARE-NUMERIC-001: exact E8M0 power-of-two scale.
pure func E8M0NumericFormatDescriptor() => NumericFormatDescriptorbegin return NumericFormatDescriptor { available = TRUE, kind = NumericFormatKind_E8M0, carrier_bits = 8, lane_bits = 8, lanes_per_carrier = 1, sign_bits = 0, sign_bit = 0, exponent_bits_min = 8, exponent_bits_max = 8, fraction_bits_min = 0, fraction_bits_max = 0, exponent_bias_available = TRUE, exponent_bias = 127, required_low_zero_bits = 0, required_high_zero_bits = 0, has_zero = FALSE, has_signed_zero = FALSE, has_subnormal = FALSE, has_infinity = FALSE, has_quiet_nan = TRUE, has_signaling_nan = FALSE };end;
pure func E8M0FiniteDecomposition(value: bits(8)) => (boolean, boolean, Word, integer {-1074..1023})begin if value == Ones{8} then return (FALSE, FALSE, Zeros{PTO_XLEN}, 0); else return (TRUE, FALSE, Zeros{PTO_XLEN} + 1, (UInt(value) - 127) as integer {-1074..1023}); end;end;
pure func HardwareNumericScaleBlockElements() => integer {32}begin return 32;end;pure func ClassifyE8M0(value: bits(8)) => NumericValueClassbegin if value == Ones{8} then return NumericValue_QuietNaN; else return NumericValue_PositiveNormal; end;end;
pure func E8M0CanonicalNaN() => Wordbegin return Zeros{PTO_XLEN} + 0xff;end;// PTO-UNIT: {"id":"PTO-ARCH-DATA-TYPES-FORMAT-E8M0","surface":"arch","classification":["data-types","formats","e8m0"],"depends_on":["PTO-ARCH-DATA-TYPES-FORMAT-DESCRIPTOR"]}// DOC-BEGIN: operation// PTO-REQ-HARDWARE-NUMERIC-001: exact E8M0 power-of-two scale.
pure func E8M0NumericFormatDescriptor() => NumericFormatDescriptorbegin return NumericFormatDescriptor { available = TRUE, kind = NumericFormatKind_E8M0, carrier_bits = 8, lane_bits = 8, lanes_per_carrier = 1, sign_bits = 0, sign_bit = 0, exponent_bits_min = 8, exponent_bits_max = 8, fraction_bits_min = 0, fraction_bits_max = 0, exponent_bias_available = TRUE, exponent_bias = 127, required_low_zero_bits = 0, required_high_zero_bits = 0, has_zero = FALSE, has_signed_zero = FALSE, has_subnormal = FALSE, has_infinity = FALSE, has_quiet_nan = TRUE, has_signaling_nan = FALSE };end;
pure func E8M0FiniteDecomposition(value: bits(8)) => (boolean, boolean, Word, integer {-1074..1023})begin if value == Ones{8} then return (FALSE, FALSE, Zeros{PTO_XLEN}, 0); else return (TRUE, FALSE, Zeros{PTO_XLEN} + 1, (UInt(value) - 127) as integer {-1074..1023}); end;end;
pure func HardwareNumericScaleBlockElements() => integer {32}begin return 32;end;pure func ClassifyE8M0(value: bits(8)) => NumericValueClassbegin if value == Ones{8} then return NumericValue_QuietNaN; else return NumericValue_PositiveNormal; end;end;
pure func E8M0CanonicalNaN() => Wordbegin return Zeros{PTO_XLEN} + 0xff;end;// DOC-END: operation
E8M0 is an assigned PTO numeric format. This page helps a reader connect its carrier layout, finite-value decomposition, and value classification; the exact contract remains in E8M0NumericFormatDescriptor, E8M0FiniteDecomposition, and ClassifyE8M0 in the ASL owner.
The descriptor uses an 8-bit carrier with one 8-bit logical lane. All 8 lane bits form the exponent field, the exponent bias is 127, and the format has no sign or fraction field.
All eight bits form an unsigned exponent field; there is no sign or fraction field.
E8M0FiniteDecomposition reports whether a finite decomposition is available and, when available, returns the sign, an integer significand, and a binary exponent. ClassifyE8M0 separately assigns the raw lane to zero, subnormal, normal, infinity, or NaN classes supported by this format.
It has no zero, signed zero, subnormal, or infinity class. Encodings 0x00 through 0xfe are positive normal powers of two, while 0xff is the quiet-NaN encoding and has no finite decomposition.
E8M0CanonicalNaN returns 0xff, and HardwareNumericScaleBlockElements fixes a scale block at 32 elements.
The finite-decomposition function reports availability with its returned tuple; value classification is a separate function result.
This example illustrates how to read the functions; it does not add an encoding rule.
For example, 0x00 decomposes to positive significand 1 with exponent -127; 0xfe uses exponent 127.
Bodies come from owning ASL. Dragging or buttons change only this page-session view order.
No NDF clause is attached to this unit.
8 matching entries
PTO-AVS-ARCH-DATA-TYPES-FORMAT-E8M0-STATIC-001tests/asl/arch/data-types/formats/e8m0/arch-static-e8m0-contract-001.asl951c81c9f71e59d75c174c839a39225ce0810020a7767f82bb1ac5904cfa4767PTO-AVS-ARCH-E8M0-DECOMP-001tests/asl/arch/data-types/formats/e8m0/arch-bound-e8m0-decomp-001.asld20f3428e308a827e0e46c767bcc5cd2ab667090bb87fe87e8d44838124bb52aPTO-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-0048…
ADR-0048docs/status/decisions/0048-numeric-format-value-classification.mdce3ecd1851e22b5517d07076ab8bd2db36b6b4582111c761db19240275853d9c{
"classification": [
"data-types",
"formats",
"e8m0"
],
"documentation": "docs/arch/data-types/formats/e8m0.md",
"id": "PTO-ARCH-DATA-TYPES-FORMAT-E8M0",
"mnemonic": null,
"readiness_subjects": [
"ADR-0048"
],
"semantic_tests": [
"PTO-AVS-ARCH-E8M0-DECOMP-001"
],
"source": "asl/arch/data-types/formats/e8m0.asl",
"surface": "arch",
"tests": [
"PTO-AVS-ARCH-DATA-TYPES-FORMAT-E8M0-STATIC-001",
"PTO-AVS-ARCH-E8M0-DECOMP-001"
]
}0.58.5 · Release candidate7dc8b7e5b121d2b2499a2273bebff29e2cd868128b3508513010e4aaa36ce62ef7e87b3e86d4ff2d7fc0e76175f9c4f6dcd70afc1997742c05123d0ebfdf79f971566951dd34d8fe051c7a0f03a053f7d8739edbasl/arch/data-types/formats/e8m0.asl