refactor: DequeueNextAs always points to proof item's payload

tasm-lib/src/recufier/fri_verify.rs

@@ -639,19 +639,6 @@ impl BasicSnippet for FriVerify {
             }),
         }));
 
-        // BEFORE: _ *xfe_list_size
-        // AFTER:  _ *xfe_list
-        let verifiably_access_x_field_elements_lists = triton_asm! {
-           read_mem 1          // _ size *xfe_list_size-1
-           push 2 add          // _ size *num_xfes
-           read_mem 1          // _ size num_elements *xfe_list_size
-           push 1 add          // _ size num_elements *new_list
-           swap 2 swap 1       // _ *new_list size num_elements
-           push 3 mul          // _ *new_list size num_elements*3 (<-- 3 BFEs per XFE)
-           push 1 add          // _ *new_list size num_elements*3+1 (<-- +1 for length indicator)
-           eq assert           // _ *new_list
-        };
-
         triton_asm! {
             // INVARIANT:          _ *alphas current_tree_height *a_indices *a_elements *revealed_indices_and_leafs current_domain_length r half_domain_length *b_indices *b_elements *fri_verify current_tree_height-1 half_domain_length *c_indices *c_values i
             {compute_c_values_loop}:
@@ -861,7 +848,6 @@ impl BasicSnippet for FriVerify {
                 call {proof_stream_dequeue_next_as_fri_codeword}
                     hint last_fri_codeword: ListPointer = stack[0]
                                             // _ *proof_stream *fri_verify num_rounds last_round_max_degree 0 *roots *alphas *last_codeword
-                {&verifiably_access_x_field_elements_lists}
                 dup 7 swap 1                // _ *proof_stream *fri_verify num_rounds last_round_max_degree 0 *roots *alphas *proof_iter *last_codeword
 
                 // clone last codeword for later use
@@ -956,7 +942,6 @@ impl BasicSnippet for FriVerify {
 
                 // assert correct length of number of leafs
                 {&revealed_leafs}           // _ *proof_stream *fri_verify num_rounds last_round_max_degree *last_codeword' *roots *alphas tree_height *indices *a_elements
-                {&verifiably_access_x_field_elements_lists}
                 dup 1 dup 1                 // _ *proof_stream *fri_verify num_rounds last_round_max_degree *last_codeword' *roots *alphas tree_height *indices *a_elements *indices *a_elements
                 call {length_of_list_of_xfes}
                                             // _ *proof_stream *fri_verify num_rounds last_round_max_degree *last_codeword' *roots *alphas tree_height *indices *a_elements *indices num_leafs
@@ -1052,7 +1037,6 @@ impl BasicSnippet for FriVerify {
                 call {proof_stream_dequeue_next_as_fri_response}
                                             // _ *proof_stream *fri_verify num_rounds last_round_max_degree *last_codeword' *roots *alphas current_tree_height *a_indices *a_elements *revealed_indices_and_leafs current_domain_length r half_domain_length *b_indices *fri_response
                 {&revealed_leafs}           // _ *proof_stream *fri_verify num_rounds last_round_max_degree *last_codeword' *roots *alphas current_tree_height *a_indices *a_elements *revealed_indices_and_leafs current_domain_length r half_domain_length *b_indices *b_elements
-                {&verifiably_access_x_field_elements_lists}
                 hint b_elements: Pointer = stack[0]
 
                 // if in first round (r==0), populate second half of return vector

tasm-lib/src/recufier/proof_stream/dequeue_next_as.rs

@@ -100,6 +100,23 @@ impl DequeueNextAs {
             push 2 add add      // _ *next_proof_item_size
         }
     }
+
+    /// ```text
+    /// BEFORE: _ *proof_item_size
+    /// AFTER:  _ *proof_item_payload
+    /// ```
+    fn advance_list_element_pointer_to_proof_item_payload(&self) -> Vec<LabelledInstruction> {
+        let payload_length_indicator_size = match self.proof_item.payload_static_length() {
+            Some(_) => 0,
+            None => 1,
+        };
+        let list_item_length_indicator_size = 1;
+        let discriminant_size = 1;
+        let bookkeeping_offset =
+            payload_length_indicator_size + list_item_length_indicator_size + discriminant_size;
+
+        triton_asm! { push {bookkeeping_offset} hint bookkeeping_offset = stack[0] add }
+    }
 }
 
 impl BasicSnippet for DequeueNextAs {
@@ -150,9 +167,8 @@ impl BasicSnippet for DequeueNextAs {
             {&self.update_proof_item_iter_to_next_proof_item()}
                                 // _ *proof_item_size
 
-            push 2 add          // _ *proof_item_payload
-            {final_hint}
-
+            {&self.advance_list_element_pointer_to_proof_item_payload()}
+            {final_hint}        // _ *proof_item_payload
             return
         }
     }
@@ -243,7 +259,16 @@ mod test {
         }
 
         fn proof_item_payload_pointer(&self) -> BFieldElement {
-            self.discriminant_pointer() + BFieldElement::one()
+            self.discriminant_pointer()
+                + BFieldElement::one()
+                + self.proof_item_payload_size_indicator_length()
+        }
+
+        fn proof_item_payload_size_indicator_length(&self) -> BFieldElement {
+            match self.dequeue_next_as.proof_item.payload_static_length() {
+                Some(_) => BFieldElement::zero(),
+                None => BFieldElement::one(),
+            }
         }
 
         fn assert_correct_discriminant(&self) {