Struct VmState 

pub struct VmState { /* private fields */ }

Everything a run needs beyond the program: the register file, the scratch arenas, the operand stack and the RNG.

Allocated once at preset load. A frame borrows it mutably and returns it unchanged in shape — nothing here resizes while a preset renders, which is the whole of the real-time claim.

Implementations

impl VmState

pub fn new(registers: usize, stack_depth: usize, salt: u32) -> Self

Allocate for a program of registers registers and stack_depth operand slots, with the RNG seeded from salt.

Sized for the largest of a bundle’s programs by the caller, so the three of them share one state and the values a per-frame program leaves in its registers are what the per-vertex program starts from — which is MilkDrop’s own execution model.

pub fn accommodate(&mut self, program: &EelProgram)

Grow the register file and operand stack to hold program, if they do not already. Load-time only — called when a bundle’s programs are attached, never per frame.

pub fn get(&self, index: u16) -> f32

Read register index, or 0 for one that does not exist.

pub fn set(&mut self, index: u16, value: f32)

Write register index, ignoring one that does not exist.

pub fn clear_registers(&mut self)

Zero every register — what a preset switch does before the first per_frame_init run.

pub fn clear_memory(&mut self)

Zero both scratch arenas. Load-time: a preset must not inherit the previous one’s megabuf.

pub fn reset_rng(&mut self)

Restore the RNG to its seed, so a re-run of a preset from frame zero draws the same sequence (ADR-0051 / NFR §6).