Struct Builder 

pub struct Builder { /* private fields */ }

Straight-line program builder over virtual values.

Each method appends one operation (or, for lookups, a run of scan steps) in program order and returns the virtual value it defines. Nothing is scheduled until Self::compile.

Implementations

impl Builder

pub fn new() -> Self

Create an empty builder.

pub fn constant(&mut self, value: Fp) -> V

Reference a constant, deduplicated.

pub fn mul(&mut self, a: V, b: V) -> V

a * b. Bank L can feed only the second factor, so a must not be a lookup coordinate.

pub fn sqr(&mut self, a: V) -> V

a^2.

pub fn pow2k(&mut self, a: V, k: u32) -> V

a^(2^k): k successive squarings.

pub fn add(&mut self, a: V, b: V) -> V

a + b. The add unit cannot read bank L.

pub fn sub(&mut self, a: V, b: V) -> V

a - b. The add unit cannot read bank L.

pub fn out(&mut self, a: V, index: u8)

Emit a with output index index; outputs keep program order.

pub fn lookup(&mut self, digit: u8) -> [V; 3]

Constant-address lookup of signed digit digit into bank L.

pub fn lookup_key(&mut self, digit: u8) -> [V; 3]

Constant-address lookup of digit digit of the second scalar (digit slot 64 + digit) in the per-key table.

pub fn invert(&mut self, x: V) -> V

a^(p-2) with Dalek’s 254-square, 11-multiply addition chain. Inversion by Fermat’s little theorem uses only the multiplier and runs in a fixed number of bundles; zero maps to zero.

pub fn pow_p58(&mut self, x: V) -> V

a^((p-5)/8) ((x^(2^250-1))^4 * x), for square roots.

pub fn compile(self, name: &'static str) -> Program

Schedule into bundles and allocate bank registers.

Three passes: build ordering constraints between operations, list-schedule them into bundles by critical-path height, then assign physical M and A registers from the scheduled value lifetimes. Because the barrel makes every result visible to the next bundle, a dependency only needs the consumer to sit in a later bundle than the producer.

Trait Implementations

impl Default for Builder

fn default() -> Builder

Returns the “default value” for a type.