Struct LogosDivU64 

pub struct LogosDivU64 { /* private fields */ }

Precomputed unsigned division by a loop-invariant runtime divisor — the magic-multiply that replaces a hardware div/idiv once the divisor is pinned. Codegen emits LogosDivU64::new(n) in a loop’s preheader (computed ONCE) and rewrites each in-loop x % n / x / n to .rem(x) / .div(x), turning a ~20–40-cycle division into a multiply-high plus a shift. gcc and rustc both leave a runtime-invariant divisor as a real div (neither synthesizes this), so it is a strict win over the C baseline on division-hot loops (graph_bfs’s % n adjacency build).

The construction is the standard Granlund–Montgomery / libdivide unsigned algorithm, exact for every divisor in 1..=u64::MAX (power-of-two fast path, the 64-bit-magic path, and the 65-bit “add marker” path). Codegen only emits it where the dividend is proven non-negative and n > 0 (the existing positivity guard), so the i64→u64 reinterpretation is value-preserving.

Implementations

impl LogosDivU64

pub fn new(d: u64) -> Self

Build the magic numbers for divisor d (must be non-zero). Runs once per loop in the preheader, so its cost (a single 128/64 division) amortizes over the whole loop.

pub fn div(&self, numer: u64) -> u64

pub fn rem(&self, numer: u64) -> u64

pub fn parts(&self) -> (u64, u8)

The raw (magic, more) pair, for backends (the VM / JIT interpreter tiers) that bake the precomputed constants into a single fused op instead of holding a LogosDivU64 struct. The encoding of more is exactly the one div/rem consume (low 6 bits = shift; 0x40 = the 65-bit add-marker path; 0x80 = the pure-shift power-of-two path).

Trait Implementations

impl Clone for LogosDivU64

fn clone(&self) -> LogosDivU64

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LogosDivU64

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

Formats the value using the given formatter.

impl Copy for LogosDivU64