provekit-common 0.1.2

Common types and utilities for the ProveKit proving system
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

// Masking constants (sanitycheck only) for AND and XOR opcode lookup tables
pub const U8_BIN_LHS_MASK: u32 = 0b000000000000000011111111;
pub const U8_BIN_RHS_MASK: u32 = 0b000000001111111100000000;
pub const U8_BIN_OUT_MASK: u32 = 0b111111110000000000000000;

pub const LHS_SHIFT_FACTOR: u32 = 1 << 0;
pub const RHS_SHIFT_FACTOR: u32 = 1 << 8;
pub const OUTPUT_SHIFT_FACTOR: u32 = 1 << 16;

/// Making it slightly easier to generalize the functions for binary operations.
/// Not using this currently.
#[derive(Clone, Debug, Copy)]
pub enum BinOp {
    AND,
    XOR,
}

/// We assume that the inputs being passed in are `u8`s, but we need to output
/// a `u32` since the final representation is the concatenation
pub fn compute_compact_bin_op_logup_repr(lhs: u8, rhs: u8, op: BinOp) -> u32 {
    let raw_result = match op {
        BinOp::AND => lhs & rhs,
        BinOp::XOR => lhs ^ rhs,
    };
    let table_val = (lhs as u32 * LHS_SHIFT_FACTOR)
        + (rhs as u32 * RHS_SHIFT_FACTOR)
        + raw_result as u32 * OUTPUT_SHIFT_FACTOR;
    // --- Sanitycheck ---
    debug_assert_eq!(
        match op {
            BinOp::AND => (table_val & U8_BIN_LHS_MASK) & ((table_val & U8_BIN_RHS_MASK) >> 8),
            BinOp::XOR => (table_val & U8_BIN_LHS_MASK) ^ ((table_val & U8_BIN_RHS_MASK) >> 8),
        },
        (table_val & U8_BIN_OUT_MASK) >> 16
    );
    table_val
}