Method _add_ref_inner

bitvm/src/bigint/add.rs:312–349

Underlying add_ref implementation used by both `add_ref` and `add_ref_stack` functions. The commented section is supposed to handle depth=0, which fails. This adds to the script size, henced we assume that the caller ensures that the depth > 0

()

    // This adds to the script size, henced we assume that the caller ensures that
    // the depth > 0
    fn _add_ref_inner() -> Script {
        script! {
            // OP_DUP OP_NOT OP_NOT OP_VERIFY // fail on {0} stack
            // OP_DUP OP_NOT
            // OP_IF
            //     OP_DROP
            //     { Self::topadd_new(0) }
            // OP_ELSE
                3 OP_ADD
                { 1 << LIMB_SIZE }
                for i in 0..Self::N_LIMBS-1 {
                    if i == 0 {
                        OP_OVER OP_1SUB
                        OP_PICK
                    } else {
                        2 OP_PICK
                        OP_PICK
                        OP_ADD
                    }
                    3 OP_ROLL
                    OP_ADD
                    OP_2DUP
                    OP_LESSTHANOREQUAL
                    OP_TUCK
                    OP_IF 2 OP_PICK OP_SUB OP_ENDIF
                    OP_TOALTSTACK
                }
                OP_NIP OP_SWAP
                2 OP_SUB OP_PICK

                OP_SWAP { limb_add_with_carry_prevent_overflow(Self::HEAD_OFFSET) }

                for _ in 0..Self::N_LIMBS-1 {
                    OP_FROMALTSTACK
                }
            // OP_ENDIF
        }
    }
}

pub fn limb_add_create_carry() -> Script {