Struct StackState 

pub struct StackState {
    pub stack_top: [Felt; 16],
    /* private fields */
}

This struct captures the state of the top 16 elements of the stack at a specific clock cycle; that is, those elements that are written directly into the trace.

The stack trace consists of 19 columns total: 16 stack columns + 3 helper columns. The helper columns (stack_depth, overflow_addr, and overflow_helper) are computed from the stack_depth and last_overflow_addr fields.

Fields

stack_top: [Felt; 16]

Top 16 stack slots (s0 to s15). These represent the top elements of the stack that are directly accessible.

Implementations

impl StackState

pub fn new( stack_top: [Felt; 16], stack_depth: usize, last_overflow_addr: Felt, ) -> Self

Creates a new StackState with the provided parameters.

stack_top should be the top 16 elements of the stack stored in reverse order, i.e., stack_top[15] is the topmost element (s0), and stack_top[0] is the bottommost element (s15).

pub fn get(&self, index: usize) -> Felt

Returns the value at the specified index in the stack top.

Panics

• if the index is greater than or equal to MIN_STACK_DEPTH.

pub fn stack_depth(&self) -> usize

Returns the stack depth (b0 helper column)

pub fn overflow_addr(&mut self) -> Felt

Returns the overflow address (b1 helper column) using the stack overflow replay

pub fn num_overflow_elements_in_current_ctx(&self) -> usize

Returns the number of elements in the current context’s overflow stack.

pub fn push_overflow(&mut self, _element: Felt, clk: RowIndex)

Pushes the given element onto the overflow stack at the provided clock cycle.

pub fn pop_overflow( &mut self, stack_overflow_replay: &mut StackOverflowReplay, ) -> Option<Felt>

Pops the top element from the overflow stack at the provided clock cycle, if any.

If the overflow table is empty (i.e. stack depth is 16), the stack depth is unchanged, and None is returned.

pub fn overflow_helper(&self) -> Felt

Derives the denominator of the overflow helper (h0 helper column) from the current stack depth.

It is expected that this values gets later inverted via batch inversion.

pub fn start_context(&mut self) -> (usize, Felt)

Starts a new execution context for this stack and returns a tuple consisting of the current stack depth and the address of the overflow table row prior to starting the new context.

This has the effect of hiding the contents of the overflow table such that it appears as if the overflow table in the new context is empty.

pub fn restore_context( &mut self, stack_overflow_replay: &mut StackOverflowReplay, )

Restores the prior context for this stack.

This has the effect bringing back items previously hidden from the overflow table.

Trait Implementations

impl Debug for StackState

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

Formats the value using the given formatter.