Handle additional memory requests made by RCOMBBASE (#1229)

air/src/trace/main_trace.rs

@@ -1,7 +1,7 @@
-use super::super::ColMatrix;
 use super::{
+    super::ColMatrix,
     chiplets::{
-        hasher::{DIGEST_LEN, STATE_WIDTH},
+        hasher::{DIGEST_LEN, HASH_CYCLE_LEN, STATE_WIDTH},
         BITWISE_A_COL_IDX, BITWISE_B_COL_IDX, BITWISE_OUTPUT_COL_IDX, HASHER_NODE_INDEX_COL_IDX,
         HASHER_STATE_COL_RANGE, MEMORY_ADDR_COL_IDX, MEMORY_CLK_COL_IDX, MEMORY_CTX_COL_IDX,
         MEMORY_V_COL_RANGE,
@@ -92,19 +92,9 @@ impl MainTrace {
         self.addr(i) != self.addr(i + 1)
     }
 
-    /// First decoder helper register at row i.
-    pub fn helper_0(&self, i: usize) -> Felt {
-        self.columns.get_column(DECODER_TRACE_OFFSET + USER_OP_HELPERS_OFFSET)[i]
-    }
-
-    /// Second decoder helper register at row i.
-    pub fn helper_1(&self, i: usize) -> Felt {
-        self.columns.get_column(DECODER_TRACE_OFFSET + USER_OP_HELPERS_OFFSET + 1)[i]
-    }
-
-    /// Third decoder helper register at row i.
-    pub fn helper_2(&self, i: usize) -> Felt {
-        self.columns.get_column(DECODER_TRACE_OFFSET + USER_OP_HELPERS_OFFSET + 2)[i]
+    /// The i-th decoder helper register at `row`.
+    pub fn helper_register(&self, i: usize, row: usize) -> Felt {
+        self.columns.get_column(DECODER_TRACE_OFFSET + USER_OP_HELPERS_OFFSET + i)[row]
     }
 
     /// Returns the hasher state at row i.
@@ -405,7 +395,7 @@ impl MainTrace {
     /// Returns `true` if the hasher chiplet flags indicate the initialization of verifying
     /// a Merkle path to an old node during Merkle root update procedure (MRUPDATE).
     pub fn f_mv(&self, i: usize) -> bool {
-        (i % 8 == 0)
+        (i % HASH_CYCLE_LEN == 0)
             && self.chiplet_selector_0(i) == ZERO
             && self.chiplet_selector_1(i) == ONE
             && self.chiplet_selector_2(i) == ONE
@@ -415,7 +405,7 @@ impl MainTrace {
     /// Returns `true` if the hasher chiplet flags indicate the continuation of verifying
     /// a Merkle path to an old node during Merkle root update procedure (MRUPDATE).
     pub fn f_mva(&self, i: usize) -> bool {
-        (i % 8 == 7)
+        (i % HASH_CYCLE_LEN == HASH_CYCLE_LEN - 1)
             && self.chiplet_selector_0(i) == ZERO
             && self.chiplet_selector_1(i) == ONE
             && self.chiplet_selector_2(i) == ONE
@@ -425,7 +415,7 @@ impl MainTrace {
     /// Returns `true` if the hasher chiplet flags indicate the initialization of verifying
     /// a Merkle path to a new node during Merkle root update procedure (MRUPDATE).
     pub fn f_mu(&self, i: usize) -> bool {
-        (i % 8 == 0)
+        (i % HASH_CYCLE_LEN == 0)
             && self.chiplet_selector_0(i) == ZERO
             && self.chiplet_selector_1(i) == ONE
             && self.chiplet_selector_2(i) == ONE
@@ -435,7 +425,7 @@ impl MainTrace {
     /// Returns `true` if the hasher chiplet flags indicate the continuation of verifying
     /// a Merkle path to a new node during Merkle root update procedure (MRUPDATE).
     pub fn f_mua(&self, i: usize) -> bool {
-        (i % 8 == 7)
+        (i % HASH_CYCLE_LEN == HASH_CYCLE_LEN - 1)
             && self.chiplet_selector_0(i) == ZERO
             && self.chiplet_selector_1(i) == ONE
             && self.chiplet_selector_2(i) == ONE

docs/src/design/stack/crypto_ops.md

@@ -178,4 +178,28 @@ After calling the `mem_stream ` with `x_ptr`, the operation does the following:
 > TODO: add detailed constraint descriptions. See discussion [here](https://github.com/0xPolygonMiden/miden-vm/issues/869).
 
 The effect on the rest of the stack is:
-* **No change.**
+* **No change.**
+
+The `RCOMBBASE` makes two memory access request. To simplify the description of these, we first define the following variables :
+
+$$
+v_1 = \sum_{i=0}^3\alpha_{i+5} \cdot h_{i}
+$$
+
+$$
+v_2 = \sum_{i=0}^1\alpha_{i+5} \cdot h_{i + 4}
+$$
+
+Using the above variables, we define the values representing the memory access request as follows:
+
+$$
+u_{mem, 1} = \alpha_0 + \alpha_1 \cdot op_{mem\_read} + \alpha_2 \cdot ctx + \alpha_3 \cdot s_{13} + \alpha_4 \cdot clk + v_1
+$$
+
+$$
+u_{mem, 2} = \alpha_0 + \alpha_1 \cdot op_{mem\_read} + \alpha_2 \cdot ctx + \alpha_3 \cdot s_{14} + \alpha_4 \cdot clk + v_2
+$$
+
+$$
+u_{mem} = u_{mem, 1} \cdot u_{mem, 2}
+$$

docs/src/design/stack/op_constraints.md

@@ -188,7 +188,7 @@ This group contains operations which require constraints with degree up to $3$.
 | `SPAN`       | $86$         | `101_0110`      | [Flow control ops](../decoder/main.md) | $5$         |
 | `JOIN`       | $87$         | `101_0111`      | [Flow control ops](../decoder/main.md) | $5$         |
 | `DYN`        | $88$         | `101_1000`      | [Flow control ops](../decoder/main.md) | $5$         |
-| `RCombBase`  | $89$         | `101_1001`      | [Crypto ops](./crypto_ops.md)          | $5$         |
+| `RCOMBBASE`  | $89$         | `101_1001`      | [Crypto ops](./crypto_ops.md)          | $5$         |
 | `<unused>`   | $90$         | `101_1010`      |                                        | $5$         |
 | `<unused>`   | $91$         | `101_1011`      |                                        | $5$         |
 | `<unused>`   | $92$         | `101_1100`      |                                        | $5$         |