miden-processor 0.9.2

Miden VM processor
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98

use super::{AuxColumnBuilder, Felt, FieldElement, MainTrace, ONE, PUSH, RESPAN, SPAN};
use miden_air::trace::decoder::{OP_BATCH_2_GROUPS, OP_BATCH_4_GROUPS, OP_BATCH_8_GROUPS};

// OP GROUP TABLE COLUMN
// ================================================================================================

/// Builds the execution trace of the decoder's `p3` column which describes the state of the op
/// group table via multiset checks.
#[derive(Default)]
pub struct OpGroupTableColumnBuilder {}

impl<E: FieldElement<BaseField = Felt>> AuxColumnBuilder<E> for OpGroupTableColumnBuilder {
    /// Removes a row from the block hash table.
    fn get_requests_at(&self, main_trace: &MainTrace, alphas: &[E], i: usize) -> E {
        let delete_group_flag = main_trace.delta_group_count(i) * main_trace.is_in_span(i);

        if delete_group_flag == ONE {
            get_op_group_table_removal_multiplicand(main_trace, i, alphas)
        } else {
            E::ONE
        }
    }

    /// Adds a row to the block hash table.
    fn get_responses_at(&self, main_trace: &MainTrace, alphas: &[E], i: usize) -> E {
        let op_code_felt = main_trace.get_op_code(i);
        let op_code = op_code_felt.as_int() as u8;

        match op_code {
            SPAN | RESPAN => get_op_group_table_inclusion_multiplicand(main_trace, i, alphas),
            _ => E::ONE,
        }
    }
}

// HELPER FUNCTIONS
// ================================================================================================

/// Computes the multiplicand representing the inclusion of a new row to the op group table.
fn get_op_group_table_inclusion_multiplicand<E: FieldElement<BaseField = Felt>>(
    main_trace: &MainTrace,
    i: usize,
    alphas: &[E],
) -> E {
    let block_id = main_trace.addr(i + 1);
    let group_count = main_trace.group_count(i);
    let op_batch_flag = main_trace.op_batch_flag(i);

    if op_batch_flag == OP_BATCH_8_GROUPS {
        let h = main_trace.decoder_hasher_state(i);
        (1..8_u8).fold(E::ONE, |acc, k| {
            acc * (alphas[0]
                + alphas[1].mul_base(block_id)
                + alphas[2].mul_base(group_count - Felt::from(k))
                + alphas[3].mul_base(h[k as usize]))
        })
    } else if op_batch_flag == OP_BATCH_4_GROUPS {
        let h = main_trace.decoder_hasher_state_first_half(i);
        (1..4_u8).fold(E::ONE, |acc, k| {
            acc * (alphas[0]
                + alphas[1].mul_base(block_id)
                + alphas[2].mul_base(group_count - Felt::from(k))
                + alphas[3].mul_base(h[k as usize]))
        })
    } else if op_batch_flag == OP_BATCH_2_GROUPS {
        let h = main_trace.decoder_hasher_state_first_half(i);
        alphas[0]
            + alphas[1].mul_base(block_id)
            + alphas[2].mul_base(group_count - ONE)
            + alphas[3].mul_base(h[1])
    } else {
        E::ONE
    }
}

/// Computes the multiplicand representing the removal of a row from the op group table.
fn get_op_group_table_removal_multiplicand<E: FieldElement<BaseField = Felt>>(
    main_trace: &MainTrace,
    i: usize,
    alphas: &[E],
) -> E {
    let group_count = main_trace.group_count(i);
    let block_id = main_trace.addr(i);

    let op_code = main_trace.get_op_code(i);
    let tmp = if op_code == Felt::from(PUSH) {
        main_trace.stack_element(0, i + 1)
    } else {
        let h0 = main_trace.decoder_hasher_state_first_half(i + 1)[0];

        let op_prime = main_trace.get_op_code(i + 1);
        h0.mul_small(1 << 7) + op_prime
    };
    alphas[0]
        + alphas[1].mul_base(block_id)
        + alphas[2].mul_base(group_count)
        + alphas[3].mul_base(tmp)
}