diff --git a/nova/src/circuit_builder.rs b/nova/src/circuit_builder.rs
index 233632ec82..66da2b3c34 100644
--- a/nova/src/circuit_builder.rs
+++ b/nova/src/circuit_builder.rs
@@ -148,13 +148,12 @@ pub(crate) fn nova_prove<T: FieldElement>(
         .collect::<BTreeMap<String, (Vec<Param>, Vec<Param>)>>();
 
     // firstly, compile pil ROM to simple memory commitment
-    // Idea to represent a instruction is by linear combination lc(<incr index>, operand1, operand2, operand3, ...),
-    // operand can be register or constant. For register, first we translate to register index
-    // decomposed(inst_encoded, 2 << LIMB_WIDTH) = [<incr index>, operand1, operand2, operand3...]
-    // each operand should be fit into 2 << LIMB_WIDTH
-    // TODO1: move this part to other place, like params generator
+    // Idea to represent a instruction is by linear combination lc(instruction,input params.., output params..)
+    // params can be register or constant. For register, first we translate to register index
+    // decomposed(inst_encoded, 1 << LIMB_WIDTH) = [<instr index>, operand1, operand2, operand3...]
+    // each operand should be fit into 1 << LIMB_WIDTH
+    // TODO1: move this part to setup stage.
     // TODO2: replace this part with more efficient memory commitment strategy, e.g. folding KZG
-    // TODO3: figure out how to encode constant
 
     let rom = main_machine.rom.as_ref().map(|rom| {
         rom.statements.iter().map(|statement| match statement {
diff --git a/nova/zero.asm b/nova/zero.asm
index 8e8a4b37b7..ba8a7406db 100644
--- a/nova/zero.asm
+++ b/nova/zero.asm
@@ -12,7 +12,7 @@ machine NovaZero {
     reg x1;
 
     constraints {
-        col witness x_b0; // TODO support to 64
+        col witness x_b0;
         col witness x_b1;
         col witness x_b2;
         col witness x_b3;