miden_processor/
utils.rs

1use alloc::{sync::Arc, vec::Vec};
2
3use vm_core::mast::{ExternalNode, MastForest, MastNodeId};
4// RE-EXPORTS
5// ================================================================================================
6pub use vm_core::utils::*;
7
8use super::Felt;
9use crate::{ErrorContext, ExecutionError, Host};
10
11// HELPER FUNCTIONS
12// ================================================================================================
13
14/// Returns the number of rows in the provided execution trace assumed to be in column-major form
15/// and contain at least one column.
16pub(crate) fn get_trace_len(trace: &[Vec<Felt>]) -> usize {
17    trace[0].len()
18}
19
20/// Splits an element into two field elements containing 32-bit integer values
21#[inline(always)]
22pub(crate) fn split_element(value: Felt) -> (Felt, Felt) {
23    let value = value.as_int();
24    let lo = (value as u32) as u64;
25    let hi = value >> 32;
26    (Felt::new(hi), Felt::new(lo))
27}
28
29/// Splits an element into two 16 bit integer limbs. It assumes that the field element contains a
30/// valid 32-bit integer value.
31pub(crate) fn split_element_u32_into_u16(value: Felt) -> (Felt, Felt) {
32    let (hi, lo) = split_u32_into_u16(value.as_int());
33    (Felt::new(hi as u64), Felt::new(lo as u64))
34}
35
36/// Splits a u64 integer assumed to contain a 32-bit value into two u16 integers.
37///
38/// # Errors
39/// Fails in debug mode if the provided value is not a 32-bit value.
40pub(crate) fn split_u32_into_u16(value: u64) -> (u16, u16) {
41    const U32MAX: u64 = u32::MAX as u64;
42    debug_assert!(value <= U32MAX, "not a 32-bit value");
43
44    let lo = value as u16;
45    let hi = (value >> 16) as u16;
46
47    (hi, lo)
48}
49
50/// Resolves an external node reference to a procedure root using the `MastForest` store in the
51/// provided host.
52///
53/// This helper function is extracted to ensure that [`crate::Process`] and
54/// [`crate::fast::FastProcessor`] resolve external nodes in the same way.
55pub(crate) fn resolve_external_node(
56    external_node: &ExternalNode,
57    host: &mut impl Host,
58) -> Result<(MastNodeId, Arc<MastForest>), ExecutionError> {
59    let node_digest = external_node.digest();
60    let mast_forest =
61        host.get_mast_forest(&node_digest)
62            .ok_or(ExecutionError::no_mast_forest_with_procedure(
63                node_digest,
64                &ErrorContext::default(),
65            ))?;
66
67    // We limit the parts of the program that can be called externally to procedure
68    // roots, even though MAST doesn't have that restriction.
69    let root_id = mast_forest.find_procedure_root(node_digest).ok_or(
70        ExecutionError::malfored_mast_forest_in_host(node_digest, &ErrorContext::default()),
71    )?;
72
73    // if the node that we got by looking up an external reference is also an External
74    // node, we are about to enter into an infinite loop - so, return an error
75    if mast_forest[root_id].is_external() {
76        return Err(ExecutionError::CircularExternalNode(node_digest));
77    }
78
79    Ok((root_id, mast_forest))
80}
miden_processor/utils.rs

miden_processor/
utils.rs
