Execute the read hotshot commitment opcode

src/osp/OneStepProofEntry.sol

@@ -113,7 +113,8 @@ contract OneStepProofEntry is IOneStepProofEntry {
         } else if (
             (opcode >= Instructions.GET_GLOBAL_STATE_BYTES32 &&
                 opcode <= Instructions.SET_GLOBAL_STATE_U64) ||
-            (opcode >= Instructions.READ_PRE_IMAGE && opcode <= Instructions.HALT_AND_SET_FINISHED)
+            (opcode >= Instructions.READ_PRE_IMAGE && opcode <= Instructions.HALT_AND_SET_FINISHED) ||
+            (opcode == Instructions.READ_HOTSHOT_COMMITMENT)
         ) {
             prover = proverHostIo;
         } else {

src/osp/OneStepProverHostIo.sol

@@ -202,6 +202,47 @@ contract OneStepProverHostIo is IOneStepProver {
         return true;
     }
 
+    function executeReadHotShotCommitment(
+        ExecutionContext calldata execCtx,
+        Machine memory mach,
+        Module memory mod,
+        Instruction calldata,
+        bytes calldata proof
+    ) internal view {
+        uint256 height = mach.valueStack.pop().assumeI64();
+        uint256 ptr = mach.valueStack.pop().assumeI32();
+
+        if (ptr + 32 > mod.moduleMemory.size || ptr % LEAF_SIZE != 0) {
+            mach.status = MachineStatus.ERRORED;
+            return;
+        }
+
+        uint256 leafIdx = ptr / LEAF_SIZE;
+        uint256 proofOffset = 0;
+        bytes32 leafContents;
+        MerkleProof memory merkleProof;
+        (leafContents, proofOffset, merkleProof) = mod.moduleMemory.proveLeaf(
+            leafIdx,
+            proof,
+            proofOffset
+        );
+
+        bytes calldata commitment = proof[proofOffset:proofOffset+32];
+        bool success = validateHotShotCommitment(execCtx, height, commitment);
+        if (!success) {
+            return;
+        }
+    }
+
+    function validateHotShotCommitment(
+        ExecutionContext calldata,
+        uint256 ,
+        bytes calldata
+    ) internal view returns (bool) {
+        // Get the hotshot commitment via the height
+        return true;
+    }
+
     function executeReadInboxMessage(
         ExecutionContext calldata execCtx,
         Machine memory mach,
@@ -348,6 +389,8 @@ contract OneStepProverHostIo is IOneStepProver {
             impl = executeReadInboxMessage;
         } else if (opcode == Instructions.HALT_AND_SET_FINISHED) {
             impl = executeHaltAndSetFinished;
+        } else if (opcode == Instructions.READ_HOTSHOT_COMMITMENT) {
+            impl = executeReadHotShotCommitment;
         } else {
             revert("INVALID_MEMORY_OPCODE");
         }

src/state/Instructions.sol

@@ -144,6 +144,8 @@ library Instructions {
     uint16 internal constant READ_INBOX_MESSAGE = 0x8021;
     uint16 internal constant HALT_AND_SET_FINISHED = 0x8022;
 
+    uint16 internal constant READ_HOTSHOT_COMMITMENT = 0x9001;
+
     uint256 internal constant INBOX_INDEX_SEQUENCER = 0;
     uint256 internal constant INBOX_INDEX_DELAYED = 1;