[Neo Core VM] complete opcode comments

src/Neo.VM/JumpTable/JumpTable.Compound.cs

@@ -239,6 +239,7 @@ public virtual void NewMap(ExecutionEngine engine, Instruction instruction)
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public virtual void Size(ExecutionEngine engine, Instruction instruction)
         {
+            // TODO: we should be able to optimize by using peek instead of dup and pop
             var x = engine.Pop();
             switch (x)
             {
@@ -410,7 +411,7 @@ public virtual void PickItem(ExecutionEngine engine, Instruction instruction)
         /// </summary>
         /// <param name="engine">The execution engine.</param>
         /// <param name="instruction">The instruction being executed.</param>
-        /// <remarks>Pop 1, Push 1</remarks>
+        /// <remarks>Pop 2, Push 0</remarks>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public virtual void Append(ExecutionEngine engine, Instruction instruction)
         {

src/Neo.VM/JumpTable/JumpTable.Numeric.cs

@@ -155,7 +155,7 @@ public virtual void Div(ExecutionEngine engine, Instruction instruction)
         }
 
         /// <summary>
-        /// Computes the result of raising a number to the specified power.
+        /// Computes the remainder after dividing a by b.
         /// <see cref="OpCode.MOD"/>
         /// </summary>
         /// <param name="engine">The execution engine.</param>
@@ -170,7 +170,7 @@ public virtual void Mod(ExecutionEngine engine, Instruction instruction)
         }
 
         /// <summary>
-        /// Computes the square root of the specified integer.
+        /// Computes the result of raising a number to the specified power.
         /// <see cref="OpCode.POW"/>
         /// </summary>
         /// <param name="engine">The execution engine.</param>
@@ -186,7 +186,7 @@ public virtual void Pow(ExecutionEngine engine, Instruction instruction)
         }
 
         /// <summary>
-        /// 
+        /// Returns the square root of a specified number.
         /// <see cref="OpCode.SQRT"/>
         /// </summary>
         /// <param name="engine">The execution engine.</param>

src/Neo.VM/JumpTable/JumpTable.Splice.cs

@@ -59,6 +59,7 @@ public virtual void Memcpy(ExecutionEngine engine, Instruction instruction)
             Types.Buffer dst = engine.Pop<Types.Buffer>();
             if (checked(di + count) > dst.Size)
                 throw new InvalidOperationException($"The value {count} is out of range.");
+            // TODO: check if we can optimize the memcpy by using peek instead of  dup then pop
             src.Slice(si, count).CopyTo(dst.InnerBuffer.Span[di..]);
         }
 

src/Neo.VM/JumpTable/JumpTable.Stack.cs

@@ -47,7 +47,7 @@ public virtual void Drop(ExecutionEngine engine, Instruction instruction)
         }
 
         /// <summary>
-        /// 
+        /// Removes the second-to-top stack item.
         /// <see cref="OpCode.NIP"/>
         /// </summary>
         /// <param name="engine">The execution engine.</param>
@@ -59,7 +59,7 @@ public virtual void Nip(ExecutionEngine engine, Instruction instruction)
         }
 
         /// <summary>
-        /// Removes the nth item from the top of the evaluation stack.
+        /// Removes the n-th item from the top of the evaluation stack.
         /// <see cref="OpCode.XDROP"/>
         /// </summary>
         /// <param name="engine">The execution engine.</param>