diff --git a/src/simulator/error.rs b/src/simulator/error.rs
index 4794315..3d922a9 100644
--- a/src/simulator/error.rs
+++ b/src/simulator/error.rs
@@ -1,3 +1,19 @@
+//! # Error
+//! 
+//! This module contains the definition of the MachineError struct,
+//! for error management in the Machine module.
+//! 
+//! Basic usage:
+//! 
+//! ```
+//! fn example(x: bool) -> Result<(), MachineError> {
+//!     match x {
+//!         true => Ok(()),
+//!         _ => Err(MachineError::new("Machine failed because of ..."));
+//!     }   
+//! }
+//! ```
+
 use std::fmt;
 
 /// Machine Error
diff --git a/src/simulator/machine.rs b/src/simulator/machine.rs
index 740ae94..8cb3b8c 100644
--- a/src/simulator/machine.rs
+++ b/src/simulator/machine.rs
@@ -1,3 +1,16 @@
+//! # Machine
+//! 
+//! This module contains a RISC-V simulator.
+//! It supports the base instruction set along
+//! with 32bit floating point operations.
+//! 
+//! Basic usage:
+//! 
+//! ```
+//! let mut machine = Machine::init_machine();
+//! machine.run();
+//! ```
+
 use std::{
 	io::Write,
 	fs::File
diff --git a/src/simulator/mod.rs b/src/simulator/mod.rs
index 956ee64..037d545 100644
--- a/src/simulator/mod.rs
+++ b/src/simulator/mod.rs
@@ -9,6 +9,7 @@ pub mod translationtable;
 pub mod mmu;
 pub mod register;
 
+/// Definition of global constants
 pub mod global {
 
     #![allow(dead_code)]
@@ -54,15 +55,15 @@ pub mod global {
     /// 
     /// See func3 to know the type of instruction (LD, LW, LH, LB, LWU, LHU, LBU)
     pub const RISCV_LD: u8 = 0x3;
-    // Store instructions
+    /// Store instructions
     pub const RISCV_ST: u8 = 0x23;
-    // immediate Arithmetic operations
+    /// immediate Arithmetic operations
     pub const RISCV_OPI: u8 = 0x13;
-    // Arithmetic operations
+    /// Arithmetic operations
     pub const RISCV_OP: u8 = 0x33;
     /// Immediate arithmetic operations for rv64i
     pub const RISCV_OPIW: u8 = 0x1b;
-    // Arithmetic operations for rv64i
+    /// Arithmetic operations for rv64i
     pub const RISCV_OPW: u8 = 0x3b;
 
     /// Type: B
diff --git a/src/simulator/register.rs b/src/simulator/register.rs
index a0ef372..339c0e5 100644
--- a/src/simulator/register.rs
+++ b/src/simulator/register.rs
@@ -1,5 +1,9 @@
-use crate::simulator::machine::{NUM_FP_REGS, NUM_INT_REGS};
+//! # Register
+//! 
+//! This mod contains the definition of the Register structs
+//! for use within the Machine module.
 
+use crate::simulator::machine::{NUM_FP_REGS, NUM_INT_REGS};
 use std::ops::{Add,  Sub};
 
 pub trait RegisterNum: Add<Output=Self> + Sub<Output=Self> + PartialEq + Copy {}
@@ -16,7 +20,6 @@ pub struct Register<U: RegisterNum> {
 }
 
 impl<U: RegisterNum> Register<U> {
-
 	/// Returns the current value held in register *position*
 	pub fn get_reg(&self, position: u8) -> U {
 		self.register[position as usize]
@@ -29,28 +32,22 @@ impl<U: RegisterNum> Register<U> {
 	pub fn set_reg(&mut self, position: u8, value: U) {
 		if position != 0 { self.register[position as usize] = value; }
 	}
-
-
 }
 
 impl Register<i64> {
-
 	/// i64 register constructor
 	pub fn init() -> Register<i64> {
 		Register { 
 			register: [0i64; NUM_INT_REGS]
 		}
 	}
-
 }
 
 impl Register<f32> {
-
 	/// f32 register constructor
 	pub fn init() -> Register<f32> {
 		Register { 
 			register: [0f32; NUM_FP_REGS]
 		}
 	}
-
 }
\ No newline at end of file