Rename unimp() to unimpl() (#118)

Summary:

Test Plan:

Co-authored-by: duc-nx <>

common/src/riscv/instruction.rs

@@ -135,7 +135,9 @@ impl Instruction {
     }
 
     /// Creates a new unimplemented instruction.
-    pub fn unimp() -> Self {
+    /// When processing an unimplemented instruction, only the opcode is checked,
+    /// and the fields op_a, op_b, and op_c are ignored.
+    pub fn unimpl() -> Self {
         Self::new(
             Opcode::from(BuiltinOpcode::UNIMPL),
             0,

common/src/riscv/opcode.rs

@@ -198,6 +198,10 @@ pub enum BuiltinOpcode {
     NOP,
 
     // Placeholder for unimplemented instructions
+    // UNIMPL instruction is used to represent instructions that are not yet implemented
+    // or are intentionally left unimplemented in the current implementation.
+    // In the RISC-V specification, this is similar to the UNIMP (unimplemented instruction) concept.
+    // Note: This may be updated or replaced if CSR (Control and Status Register) instruction support is added in the future.
     UNIMPL,
 }
 

vm/src/riscv/decoder.rs

@@ -65,9 +65,9 @@ pub fn decode_instructions(u32_instructions: &[u32]) -> BasicBlockProgram {
     let mut start_new_block = true;
 
     for &u32_instruction in u32_instructions.iter() {
-        // Decode the instruction
+        // Decode the instruction, if the instruction is unrecognizable, it will be marked as unimplemented.
         let decoded_instruction =
-            process_instruction(&mut decoder, u32_instruction).unwrap_or_else(Instruction::unimp);
+            process_instruction(&mut decoder, u32_instruction).unwrap_or_else(Instruction::unimpl);
 
         // Start a new basic block if necessary
         if start_new_block && !current_block.0.is_empty() {
@@ -147,7 +147,7 @@ pub fn decode_until_end_of_a_block(u32_instructions: &[u32]) -> BasicBlock {
 
                 // Right now, we only support the single dynamic R-type opcode.
                 if opcode != DYNAMIC_RTYPE_OPCODE {
-                    return Instruction::unimp();
+                    return Instruction::unimpl();
                 }
 
                 let fn3 = extract_fn3(u32_instruction);

vm/src/riscv/instructions/macros.rs

@@ -84,7 +84,7 @@ macro_rules! unimplemented_instructions {
     ($($name:ident($($arg:ident: $type:ty)?)),+ $(,)?) => {
         $(
             fn $name(&mut self$(, _: $type)?) -> Self::InstructionResult {
-                Instruction::unimp()
+                Instruction::unimpl()
             }
         )+
     };