Function u4_add_direct

bitvm/src/hash/blake3_utils.rs:201–244

Adds the given constant numbers and u32 variables. Variables in `to_copy` are copied and the original remains on the stack. Variables in `to_move` are consumed from the stack.

(
    stack: &mut StackTracker,
    to_copy: Vec<StackVariable>,
    mut to_move: Vec<&mut StackVariable>,
    tables: &TablesVars,
)

/// Variables in `to_copy` are copied and the original remains on the stack.
/// Variables in `to_move` are consumed from the stack.
fn u4_add_direct(
    stack: &mut StackTracker,
    to_copy: Vec<StackVariable>,
    mut to_move: Vec<&mut StackVariable>,
    tables: &TablesVars,
) {
    let nibble_count = 8;
    let number_count = to_copy.len() + to_move.len();

    for i in (0..nibble_count).rev() {
        for x in to_copy.iter() {
            stack.copy_var_sub_n(*x, i);
        }

        for x in to_move.iter_mut() {
            stack.move_var_sub_n(x, i);
        }

        //add the numbers
        for _ in 0..number_count - 1 {
            stack.op_add();
        }

        //add the carry of the previous addition
        if i < nibble_count - 1 {
            stack.op_add();
        }

        if i > 0 {
            //dup the result to be used to get the carry except for the last nibble
            stack.op_dup();
        }

        //save value
        let modulo = stack.get_value_from_table(tables.modulo, None);
        stack.rename(modulo, &format!("modulo[{}]", i).to_string());
        stack.to_altstack();

        if i > 0 {
            let carry = stack.get_value_from_table(tables.quotient, None);
            stack.rename(carry, "carry");
        }
    }
}

/// Applies the G function (same notation as the paper) with the given parameters to the variables
#[allow(clippy::too_many_arguments)]