Enum Vlmul 

#[repr(u8)]
pub enum Vlmul {
    M1 = 0,
    M2 = 1,
    M4 = 2,
    M8 = 3,
    Mf8 = 5,
    Mf4 = 6,
    Mf2 = 7,
}

Vector length multiplier (LMUL) setting

Encoded in vtype[2:0] as a signed 3-bit value. LMUL = 2^vlmul where vlmul is sign-extended. Positive values give integer multipliers, negative values give fractional.

Variants

M1 = 0

LMUL = 1 (vlmul encoding 0b000)

M2 = 1

LMUL = 2 (vlmul encoding 0b001)

M4 = 2

LMUL = 4 (vlmul encoding 0b010)

M8 = 3

LMUL = 8 (vlmul encoding 0b011)

Mf8 = 5

LMUL = 1/8 (vlmul encoding 0b101)

Mf4 = 6

LMUL = 1/4 (vlmul encoding 0b110)

Mf2 = 7

LMUL = 1/2 (vlmul encoding 0b111)

Implementations

impl Vlmul

pub const fn from_bits(bits: u8) -> Option<Self>

Decode from the 3-bit vlmul field. Returns None for reserved encoding 0b100.

pub const fn to_bits(self) -> u8

Encode to the 3-bit vlmul field

pub const fn vlmax(self, vlen_bits: u32, sew_bits: u32) -> u32

Compute VLMAX = LMUL * VLEN / SEW.

For fractional LMUL, this is VLEN / (SEW * denominator). Returns 0 when the result would be less than 1 (insufficient bits).

pub const fn register_count(self) -> u8

Number of vector registers occupied by one register group at this LMUL.

Fractional LMUL values (Mf2, Mf4, Mf8) each occupy exactly 1 register. Integer LMUL values occupy 1, 2, 4, or 8` registers respectively.

pub const fn as_fraction(self) -> (u8, u8)

LMUL as a (numerator, denominator) fraction where LMUL = num / den.

Both values are powers of two with exactly one equal to 1. Useful for computing EMUL = (EEW / SEW) * LMUL without floating-point arithmetic.

pub const fn index_register_count(self, index_eew: Eew, sew: Vsew) -> Option<u8>

Compute EMUL for an indexed load: EMUL = (index_eew / sew) * LMUL.

Returns the register count for the index register group, or None when EMUL falls outside the legal range [1/8, 8].

pub const fn data_register_count(self, eew: Eew, sew: Vsew) -> Option<u8>

Compute EMUL for a data operand of a memory instruction with a given effective element width: EMUL = (eew / sew) * LMUL.

Mathematically identical to Self::index_register_count, but exposed under a distinct name for call sites where the EEW describes the data being loaded or stored rather than an index. Keeping the two entry points separate avoids accidental semantic drift if one of them is later specialised.

Returns None when the resulting EMUL falls outside the legal range [1/8, 8].

Trait Implementations

impl Clone for Vlmul

fn clone(&self) -> Vlmul

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Vlmul

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Vlmul

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Vlmul

fn eq(&self, other: &Vlmul) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Vlmul

impl Eq for Vlmul

impl StructuralPartialEq for Vlmul