Merge branch 'bin-loader' into 'thread_scheduler'

Binary loader

See merge request simpleos/burritos!12

.gitlab-ci.yml

@@ -11,6 +11,8 @@ stages:
 unit-test-job:
   stage: test
   script:
+    - echo "Compiling c files"
+    - cd test && make build && cd ..
     - echo "Running unit tests..."
     - cargo test
 

src/kernel/mod.rs

@@ -1,4 +1,4 @@
-mod process;
+pub mod process;
 pub mod thread;
 pub mod mgerror;
 pub mod system;

src/kernel/thread.rs

@@ -16,7 +16,7 @@ macro_rules! get_new_thread {
 pub struct ThreadContext {
     pub int_registers: [i64; NUM_INT_REGS],
     pub float_registers: [f32; NUM_FP_REGS],
-    pub pc: i64,
+    pub pc: u64,
 }
 
 #[derive(PartialEq, Debug)]
@@ -47,10 +47,10 @@ impl Thread {
         }
     }
 
-    pub fn init_thread_context(&mut self, initial_pc_reg: i64, initial_sp: i64, arg: i64) {
+    pub fn init_thread_context(&mut self, initial_pc_reg: u64, initial_sp: u64, arg: i64) {
         self.thread_context.pc = initial_pc_reg;
         self.thread_context.int_registers[10] = arg;
-        self.thread_context.int_registers[STACK_REG] = initial_sp;
+        self.thread_context.int_registers[STACK_REG] = initial_sp as i64;
     }
 
     pub fn init_simulator_context(&self, base_stack_addr: [i8; SIMULATORSTACKSIZE]) {

src/kernel/thread_manager.rs

@@ -78,17 +78,19 @@ impl ThreadManager {
                 }
             },
             None => {
-
+                self.thread_restore_processor_state(machine, Rc::clone(&next_thread));
+                // next_thread.restore_simulator_state();
+                self.set_g_current_thread(Some(next_thread));
             }
         }
     }
 
     /// Start a thread, attaching it to a process
-    pub fn start_thread(&mut self, thread: Rc<RefCell<Thread>>, owner: Process, func_pc: i64, argument: i64) {
+    pub fn start_thread(&mut self, thread: Rc<RefCell<Thread>>, owner: Process, func_pc: u64, sp_loc: u64, argument: i64) {
         let mut thread_m = thread.borrow_mut();
         assert_eq!(thread_m.process, Option::None);
         thread_m.process = Option::Some(owner);
-        let ptr = 0; // todo addrspace
+        let ptr = sp_loc; // todo addrspace
         thread_m.init_thread_context(func_pc, ptr, argument);
         let base_stack_addr: [i8; SIMULATORSTACKSIZE] = [0; SIMULATORSTACKSIZE]; // todo AllocBoundedArray
         thread_m.init_simulator_context(base_stack_addr);
@@ -153,6 +155,7 @@ impl ThreadManager {
         for i in 0..NUM_FP_REGS {
             t.thread_context.float_registers[i] = machine.read_fp_register(i);
         }
+        t.thread_context.pc = machine.pc;
     }
 
     /// Restore the CPU state of a user program on a context switch.
@@ -161,6 +164,7 @@ impl ThreadManager {
         for i in 0..NUM_INT_REGS {
             machine.write_int_register(i, t.thread_context.int_registers[i]);
         }
+        machine.pc = t.thread_context.pc;
     }
 
     /// Currently running thread
@@ -196,28 +200,33 @@ impl ThreadManager {
 mod test {
     use std::{rc::Rc, cell::RefCell};
 
-    use crate::{simulator::machine::Machine, kernel::{system::System, thread::Thread, process::Process}};
+    use crate::{simulator::{machine::Machine, loader}, kernel::{system::System, thread::Thread, process::Process}};
 
     #[test]
+    #[ignore = "Pas encore terminé, contient des bugs"]
     fn test_thread_context() {
         let mut machine = Machine::init_machine();
-        let mut system = System::default();
+        let (loader, ptr) = loader::Loader::new("./test/riscv_instructions/simple_arithmetics/unsigned_addition", &mut machine, 0).expect("IO Error");
+        let start_pc = loader.elf_header.entrypoint;
+        let system = &mut System::default();
+
         let thread1 = Thread::new("th1");
         let thread1 = Rc::new(RefCell::new(thread1));
         system.get_thread_manager().get_g_alive().push(Rc::clone(&thread1));
-        let owner = Process { num_thread: 0 };
-        system.get_thread_manager().start_thread(Rc::clone(&thread1), owner, thread1_func as i64, 0);
-        assert_eq!(thread1.borrow_mut().thread_context.pc, thread1_func as i64);
-        let to_run = system.get_thread_manager().find_next_to_run().unwrap();
-        assert_eq!(to_run, Rc::clone(&thread1));
-        assert!(system.get_thread_manager().get_g_alive().contains(&Rc::clone(&thread1)));
-        system.get_thread_manager().switch_to(&mut machine, Rc::clone(&to_run));
-        
-        println!("{:#?}", thread1.borrow_mut().thread_context);
-    }
 
-    fn thread1_func() {
+        let owner = Process { num_thread: 0 };
-        println!("Hello");
+        system.get_thread_manager().start_thread(Rc::clone(&thread1), owner, start_pc, ptr, -1);
+        debug_assert_eq!(thread1.borrow_mut().thread_context.pc, start_pc);
+
+        let to_run = system.get_thread_manager().find_next_to_run().unwrap();
+        debug_assert_eq!(to_run, Rc::clone(&thread1));
+        debug_assert!(system.get_thread_manager().get_g_alive().contains(&Rc::clone(&thread1)));
+
+        system.get_thread_manager().switch_to(&mut machine, Rc::clone(&to_run));
+        debug_assert_eq!(system.get_thread_manager().g_current_thread, Option::Some(Rc::clone(&thread1)));
+        debug_assert_eq!(machine.pc, start_pc);
+
+        machine.run();
     }
 
 }

src/simulator/loader.rs

@@ -1,34 +1,650 @@
 use crate::Machine;
-
 use std::fs;
-use std::io;
+use std::io::Read;
-use std::io::BufRead;
 
-
+/// load a 32-bits binary file into the machine
-
+/// 
-	/// Load a file into a new machine
+/// ### Parameters
-	/// 
+/// 
-	/// `panic!` when size is not 1, 2, 4 or 8
+/// - **path** path of the file to load
-    /// `panic!` when the text does not represents instructions in hexadecimal
+/// - **machine** the machine where the bin file will be loaded
-	/// 
+/// - **start_index** at which index of machine memory you want to start to load the program
-	/// ### Parameters
+/// 
-	/// 
+/// Returns in a Result any io error
-	/// - **path** the path of the file to load
+pub fn load(path: &str, machine: &mut Machine, start_index: usize) -> Result<(), std::io::Error> {
-	/// - **size** the number of bytes to write (1, 2, 4 or 8)
+    let mut file = fs::File::open(path)?;
-pub fn _load(path : &str, instruction_size: i32) -> Machine {
+    let mut instructions: Vec<u32> = Default::default();
-    let file = fs::File::open(path).expect("Wrong filename");
+    loop {
-    let reader = io::BufReader::new(file);
+        let mut buf: [u8; 4] = [0; 4];
-    let mut machine = Machine::init_machine();
+        let res = file.read(&mut buf)?;
-
+        if res == 0 {
-    for (i,line) in reader.lines().enumerate() {
+            break; // eof
-        let res = u64::from_str_radix(&line.unwrap(), 16);
+        } else {
-        match res {
+            instructions.push(u32::from_le_bytes(buf));
-            Ok(value) => {
-                Machine::write_memory(&mut machine, instruction_size, i*instruction_size as usize, value);
-            },
-            _ => panic!()
         }
     }
-    println!("{:x}", Machine::read_memory(& mut machine, 4, 0));
+    for (i, inst)  in instructions.iter().enumerate() {
-    machine
+        machine.write_memory(4, 4 * i + start_index, inst.to_owned() as u64);
+    }
+    // #[cfg(debug_assertions)]
+    // println!("{:04x?}", instructions); // only print loaded program in debug build
+    Ok(())
+}
+
+/// The elf header defines principes aspects of the binary files, it's place at the start of the file
+/// see <https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#File_header> for more informations
+pub struct ElfHeader {
+    /// Defines whether the file is big or little endian
+    /// true correspond to big endian, false otherwise
+    /// 
+    /// Offset: 0x05, size: 1 byte
+    pub endianess: bool,
+    /// Defines whether the file is 32 bits or 64 bits
+    /// 
+    /// Offset: 0x04, size: 1 byte
+    pub is_32bits: bool,
+    /// Version of the elf file, current version is 1
+    /// 
+    /// Offset: 0x06, size: 1 byte
+    pub version: u8,
+    /// Identifies the target ABI.
+    /// 
+    /// In this implementation: Defines if the target abi is system V compliant
+    /// 
+    /// Offset: 0x07, size: 1 byte
+    pub sys_v_abi: bool,
+    /// Identifies target ISA, 0xF3 correspond to RISC-V
+    /// 
+    /// In this implementatio, true if target isa is RISC-V, false otherwise
+    /// 
+    /// Offset: 0x12, size: 2 bytes
+    pub is_riscv_target: bool,
+    /// Memory address of the entry point from w<here the process starts its execution.
+    /// If the program doesn't have an entrypoint (i.e. not an executable), the value is 0
+    /// 
+    /// Offset: 0x18, size: 4 (32 bits) or 8 (64 bits)
+    pub entrypoint: u64,
+    /// Size of the elf header, 64 bytes for 64 bits and 52 for 32 bits
+    /// 
+    /// Offset: 0x28(32 bits) or 0x34 (64 bits), size: 2 bytes
+    pub elf_header_size: u16,
+    /// Position of the first program header entry
+    /// 
+    /// Offset: 0x1C (32 bits) or 0x20 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub program_header_location: u64,
+    /// Number of entries in the progream header table
+    /// 
+    /// Offset: 0x2C (32 bits) or 0x38 (64 bits), size: 2 bytes
+    pub program_header_entries: u16,
+    /// Size of a program header entry
+    /// 
+    /// Offset: 0x2A (32 bits) or 0x36 (64 bits), size: 2 bytes
+    pub program_header_size: u16,
+    /// Position of the first section header entry
+    /// 
+    /// Offset: 0x20 (32 bits) or 0x28 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub section_header_location: u64,
+    /// Number of entries in the section header table
+    /// 
+    /// Offset: 0x30 (32 bits) or 0x3C (64 bits), size: 2 bytes
+    pub section_header_entries: u16,
+    /// Size of a section header entry
+    /// 
+    /// Offset: 0x2E (32 bits) or 0x36 (64 bits), size: 2 bytes
+    pub section_header_size: u16,
+}
+
+impl ElfHeader {
+    
+    /// return true if the 4 first bytes constitude the elf magic number
+    fn is_elf(instructions: &[u8]) -> bool {
+        instructions.get(0..4) == Option::Some(&[0x7f, 0x45, 0x4c, 0x46])
+    }
+
+    /// return true if big endian, false otherwise
+    fn check_endianess(instructions: &[u8]) -> bool {
+        instructions.get(5) == Option::Some(&2)
+    }
+
+    /// return true if file is 32 bits, false if 64 bits
+    fn is_32bits(instructions: &[u8]) -> bool {
+        instructions.get(4) == Option::Some(&1)
+    }
+
+    /// return the version of the elf file (should be 1)
+    /// Can be None if the file is smaller than 7 bytes -> the file is invalid
+    fn get_version(instructions: &[u8]) -> Option<u8> {
+        instructions.get(6).copied() // work as primitives implements Copy
+    }
+
+    /// return true if target abi of the binary file is System V, false otherwise
+    fn is_system_v_elf(instructions: &[u8]) -> bool {
+        instructions.get(7) == Option::Some(&0)
+    }
+
+    /// return true if specified target instruction set architecture is RISCV
+    fn is_riscv_isa(instructions: &[u8]) -> bool {
+        Self::get_u16_value(instructions, 0x12) == Option::Some(0xf3)
+    }
+
+    /// memory address of the entry point from where the process starts its execution
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_entrypoint(instructions: &[u8], is_32bits: bool) -> Option<u64> {
+        if is_32bits {
+            get_address_point(instructions, 0x18, true)
+        } else {
+            get_address_point(instructions, 0x18, false)
+        }
+    }
+
+    /// Memory address of the start of the program header table
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_program_header_table_location(instructions: &[u8], is_32bits: bool) -> Option<u64> {
+        if is_32bits {
+            get_address_point(instructions, 0x1c, true)
+        } else {
+            get_address_point(instructions, 0x20, false)
+        }
+    }
+
+    /// Memory address of the start of the section header table
+    ///
+    ///  ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_section_header_table_location(instructions: &[u8], is_32bits: bool) -> Option<u64> {
+        if is_32bits {
+            get_address_point(instructions, 0x20, true)
+        } else {
+            get_address_point(instructions, 0x28, false)
+        }
+    }
+
+    /// Return the size of the header, normally, 0x40 for 64 bits bin and 0x34 for 32 bits
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_elf_header_size(instructions: &[u8], is_32bits: bool) -> Option<u16> {
+        let address = if is_32bits { 0x28 } else { 0x34 };
+        Self::get_u16_value(instructions, address)
+    }
+
+    /// return the size of a program header table entry
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_program_header_size(instructions: &[u8], is_32bits: bool) -> Option<u16> {
+        let address = if is_32bits { 0x2a } else { 0x36 };
+        Self::get_u16_value(instructions, address)
+    }
+
+    /// return the number of entries in the program header
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_number_entries_program_header(instructions: &[u8], is_32bits: bool) -> Option<u16> {
+        let address = if is_32bits { 0x2c } else { 0x38 };
+        Self::get_u16_value(instructions, address)
+    }
+
+    /// Return the size of a section header table entry
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_section_header_size(instructions: &[u8], is_32bits: bool) -> Option<u16> {
+        let address = if is_32bits { 0x2e } else { 0x3a };
+        Self::get_u16_value(instructions, address)
+    }
+
+    /// Return the number of entries in the section header
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **is_32bits** defines whether the binary file is 32 bits or 64 bits
+    fn get_section_header_num_entries(instructions: &[u8], is_32bits: bool) -> Option<u16> {
+        let address = if is_32bits { 0x30 } else { 0x3c };
+        Self::get_u16_value(instructions, address)
+    }
+
+    /// Return a u16 value, usually for the size or the number of entries inside a header
+    /// 
+    /// This method retrieve 2 bytes and concatenate them assuming the file is little endian
+    /// 
+    /// ## Paramters:
+    /// 
+    /// **instructions** List of bytes of the loaded binary file
+    /// **address** Position of the first byte
+    fn get_u16_value(instructions: &[u8], address: usize) -> Option<u16> {
+        let mut bytes: [u8; 2] = [0; 2];
+        bytes[0] = instructions.get(address).copied()?;
+        bytes[1] = instructions.get(address + 1).copied()?;
+        Option::Some(u16::from_le_bytes(bytes))
+    }
+    
+}
+
+impl TryFrom<&Vec<u8>> for ElfHeader {
+    type Error = ();
+
+    fn try_from(instructions: &Vec<u8>) -> Result<Self, Self::Error> {
+        if Self::is_elf(instructions) {
+            let format = Self::is_32bits(instructions);
+            let endianess = Self::check_endianess(instructions);
+            let version = Self::get_version(instructions).ok_or(())?;
+            let is_sys_v_abi = Self::is_system_v_elf(instructions);
+            let is_rv_target = Self::is_riscv_isa(instructions);
+            let entrypoint = Self::get_entrypoint(instructions, format).ok_or(())?;
+            let elf_header_size = Self::get_elf_header_size(instructions, format).ok_or(())?;
+            let program_header_location = Self::get_program_header_table_location(instructions, format).ok_or(())?;
+            let program_header_entries = Self::get_number_entries_program_header(instructions, format).ok_or(())? ;
+            let program_header_size = Self::get_program_header_size(instructions, format).ok_or(())?;
+            let section_header_location = Self::get_section_header_table_location(instructions, format).ok_or(())?;
+            let section_header_entries = Self::get_section_header_num_entries(instructions, format).ok_or(())?;
+            let section_header_size = Self::get_section_header_size(instructions, format).ok_or(())?;
+            Ok(ElfHeader { 
+                endianess, 
+                is_32bits: format,
+                version,
+                sys_v_abi: is_sys_v_abi,
+                is_riscv_target: is_rv_target,
+                entrypoint,
+                elf_header_size,
+                program_header_location,
+                program_header_entries,
+                program_header_size,
+                section_header_location,
+                section_header_entries,
+                section_header_size
+            })
+        } else {
+            Err(())
+        }
+    }
+}
+
+
+/// Flag of a section, a section can have multiples flags by adding the values
+#[allow(clippy::enum_variant_names)]
+#[allow(dead_code)]
+pub enum FlagValue {
+    /// The section is writable
+    ShfWrite = 0x1,
+    /// The section need to be allocate/occupe memory during execution
+    ShfAlloc = 0x2,
+    /// The section need to be executable
+    ShfExecinstr = 0x4,
+    /// Section might ber merged
+    ShfMerge = 0x10,
+    /// Contain null-terminated (\0) strings
+    ShfStrings = 0x20,
+    // There is others but are unrelevant (I think)
+}
+
+/// Section header entry, contains useful informations for each sections of the binary file
+/// 
+/// see <https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#Section_header>
+#[derive(Debug)]
+pub struct SectionHeader {
+    /// Offset to a string in .shstrtab section that represent the name of this section
+    /// 
+    /// Offset: 0x0, size: 4 bytes
+    pub name_offset: u32,
+    /// Identify the type of this header
+    /// 
+    /// Offset: 0x4, size: 4 bytes
+    pub header_type: u32,
+    /// Identify the atributes of this section
+    /// 
+    /// see `Self::does_flag_contains_key(self, FlagValue)`
+    /// 
+    /// Offset: 0x8, size: 4 (32 bits) or 8 (64 bits) bytes
+    pub flags: u64,
+    /// Virtual address of the section in memory if section is loaded, 0x0 otherwise
+    /// 
+    /// Offset: 0x0C (32 bits) or 0x10 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub virt_addr: u64,
+    /// Offset of the section in the file image (binary file)
+    /// 
+    /// Offset: 0x10 (32 bits) or 0x18 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub image_offset: u64,
+    /// Size of the section in the file image, may be 0
+    /// 
+    /// Offset: 0x14 (32 bits) or 0x20 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub section_size: u64,
+    pub section_link: u32,
+    pub section_info: u32,
+    /// Contain the required alignment of the section, must be a power of 2
+    /// 
+    /// Offset: 0x20 (32 bits) or 0x30 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub required_align: u64,
+    /// Contain the size of each entry, for sections that contain fixed size entries, otherwise 0
+    /// 
+    /// Offset: 0x24 (32 bits) or 0x38 (64 bits), size: 4 (32 bits) or 8 (64 bits) bytes
+    pub entry_size: u64
+}
+
+impl SectionHeader {
+
+    /// return true if flag of this section contains / have `key`, false otherwise
+    pub fn does_flag_contains_key(&self, key: FlagValue) -> bool {
+        self.flags & key as u64 != 0
+    }
+
+    /// Return the offset to a string in .shstrtab that represents the name of this section
+    fn get_name_offset(instructions: &[u8], address: usize) -> Option<u32> {
+        get_address_point(instructions, address, true).map(|v| { v as u32 })
+                                                        // set true to return a u32
+    }
+
+    /// Return the type of header of the section
+    fn get_header_type(instructions: &[u8], address: usize) -> Option<u32> {
+        get_address_point(instructions, address + 0x4, true).map(|v| { v as u32 })
+    }
+
+    /// Return the flags of the section, can hold multiples values, see [`FlagValue`]
+    fn get_flags(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+        get_address_point(instructions, address + 0x8, is_32bits)
+    }
+
+
+    /// Return the virtual address of the section in memory if the sectino is loaded(see section flag), otherwise 0
+    fn get_virtual_address(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+        get_address_point(instructions, address + if is_32bits { 0x0C } else { 0x10 }, is_32bits)
+    }
+
+    /// Return the offset of the section in the file image (binary file)
+    fn get_image_offset(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+        get_address_point(instructions, address + if is_32bits { 0x10 } else { 0x18 }, is_32bits)
+    }
+
+    /// Return the size of the section in the file image (binary file), may be 0
+    fn get_section_size(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+        get_address_point(instructions, address + if is_32bits { 0x14 } else { 0x20 }, is_32bits)
+    }
+
+    fn get_section_link(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u32> {
+        get_address_point(instructions, address + if is_32bits { 0x18 } else { 0x28 }, false).map(|v| { v as u32 })
+    }
+
+    fn get_section_info(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u32> {
+        get_address_point(instructions, address + if is_32bits { 0x1C } else { 0x2C }, false).map(|v| { v as u32 })
+    }
+
+    /// Return the required alignment of the section, must be a power of 2
+    fn get_required_align(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+        get_address_point(instructions, address + if is_32bits { 0x20 } else { 0x30 }, is_32bits)
+    }
+
+    /// Contain the size of each entry for sections that contain fixed-size entries, otherwise 0
+    fn get_entry_size(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+        get_address_point(instructions, address + if is_32bits { 0x24 } else { 0x38 }, is_32bits)
+    }
+
+}
+
+impl TryFrom<(&[u8], u64, bool)> for SectionHeader {
+    type Error = ();
+
+    fn try_from(value: (&[u8], u64, bool)) -> Result<Self, Self::Error> {
+        let instructions = value.0;
+        let address = value.1 as usize;
+        let is_32bits = value.2;
+
+        let name_offset = Self::get_name_offset(instructions, address).ok_or(())?;
+        let header_type = Self::get_header_type(instructions, address).ok_or(())?;
+        let attribute = Self::get_flags(instructions, address, is_32bits).ok_or(())?;
+        let virt_addr = Self::get_virtual_address(instructions, address, is_32bits).ok_or(())?;
+        let image_offset = Self::get_image_offset(instructions, address, is_32bits).ok_or(())?;
+        let section_size = Self::get_section_size(instructions, address, is_32bits).ok_or(())?;
+        let section_link = Self::get_section_link(instructions, address, is_32bits).ok_or(())?;
+        let section_info = Self::get_section_info(instructions, address, is_32bits).ok_or(())?;
+        let required_align = Self::get_required_align(instructions, address, is_32bits).ok_or(())?;
+        let entry_size = Self::get_entry_size(instructions, address, is_32bits).ok_or(())?;
+        Ok(Self { name_offset, 
+            header_type, 
+            flags: attribute, 
+            virt_addr, 
+            image_offset,
+            section_size, 
+            section_link,
+            section_info,
+            required_align, 
+            entry_size  
+        })
+    }
+}
+
+/// Error enum for [`Loader`]
+#[derive(Debug)]
+pub enum LoaderError {
+    /// Correspond to std IO error
+    IOError(std::io::Error),
+    /// Others errors
+    ParsingError
+}
+
+/// Global structure of the loader, one instance per loaded files
+pub struct Loader {
+    /// List of bytes inside the binary file
+    bytes: Vec<u8>,
+    /// Elf header, see [`ElfHeader`] for more informations
+    pub elf_header: ElfHeader,
+    /// Section header table entries, see [`SectionHeader`] for more informations
+    pub sections: Vec<SectionHeader>
+}
+impl Loader {
+
+    /// # Loader constructor
+    /// 
+    /// Load the binary file given in parameter, parse it and load inside the machine memory
+    /// return the loader instance and the location of the end of the last a allocated section in memory
+    /// 
+    /// ## Parameters
+    /// 
+    /// **path**: location of the binary file on disk
+    /// **machine**: well, the risc-v simulator
+    /// **start_index**: The position at which you want to start to allocate the program
+    pub fn new(path: &str, machine: &mut Machine, start_index: usize) -> Result<(Self, u64), LoaderError> {
+        let loader = Self::load_and_parse(path)?;
+        let end_alloc = loader.load_into_machine(machine, start_index)?;
+        Ok((loader, end_alloc))
+    }
+
+    /// Try to load the binary file in memory after it been parsed
+    /// 
+    /// Binary file is loaded according to sections order and rules, see [`SectionHeader`]
+    /// 
+    /// Return the location of the end of the last a allocated section in memory
+    fn load_into_machine(&self, machine: &mut Machine, start_index: usize) -> Result<u64, LoaderError> {
+        let mut end_index = 0;
+        for i in 0..self.sections.len() {
+            let section = &self.sections[i];
+            if section.does_flag_contains_key(FlagValue::ShfAlloc) {
+                end_index = section.virt_addr + section.section_size;
+                // Can allocate to machine memory
+                for j in (0..section.section_size as usize).step_by(4) {
+                    let mut buf: [u8; 4] = [0; 4];
+                    #[allow(clippy::needless_range_loop)]
+                    for k in 0..buf.len() {
+                        buf[k] = self.bytes.get(section.image_offset as usize + j + k).copied().ok_or(LoaderError::ParsingError)?;
+                    }
+                    machine.write_memory(4, start_index + section.virt_addr as usize + j, u32::from_le_bytes(buf) as u64);
+                }
+            }
+        }
+        Ok(start_index as u64 + end_index)
+    }
+
+    /// Load the binary file and store it inside an array and try to parse it, 
+    /// useful for a lot of thing like to know which sections to allocate memory and where
+    fn load_and_parse(path: &str) -> Result<Self, LoaderError> {
+        let file = fs::File::open(path);
+        match file {
+            Ok(mut file) => {
+                let mut instructions: Vec<u8> = Default::default();
+                loop {
+                    let mut buf: [u8; 1] = [0; 1];
+                    let res = file.read(&mut buf);
+                    match res {
+                        Ok(res) => {
+                            if res == 0 {
+                                break; // eof
+                            } else {
+                                instructions.push(buf[0]);
+                            }
+                        },
+                        Err(err) => {
+                            return Err(LoaderError::IOError(err))
+                        }
+                    }
+                    
+                }
+                let elf_header = match ElfHeader::try_from(&instructions) {
+                    Ok(header) => {
+                        header
+                    },
+                    Err(_) => {
+                        return Err(LoaderError::ParsingError);
+                    }
+                };
+                let section_header = match Self::parse_section_header(&instructions, elf_header.is_32bits, elf_header.section_header_location, elf_header.section_header_entries, elf_header.section_header_size) {
+                    Ok(header) => {
+                        header
+                    },
+                    Err(_) => {
+                        return Err(LoaderError::ParsingError);
+                    }
+                };
+                // #[cfg(debug_assertions)]
+                // println!("{:04x?}", instructions); // only print loaded program in debug build
+                Ok(Self { bytes: instructions, elf_header, sections: section_header })
+            },
+            Err(err) => {
+                Err(LoaderError::IOError(err))
+            }
+        }
+    }
+
+
+    /// Try to parse sections header table
+    /// 
+    /// Create one instance of [`SectionHeader`] for each entry and store it inside an array
+    /// 
+    /// ## Parameters
+    /// 
+    /// **instructions**: array of bytes of the binary file
+    /// **is_32bits**: contain whether the binary file is 32 bits or 64 bits
+    /// **header_location**: represent the position of the first entry of the header
+    /// **num_of_entries**: defines the number of section header entries
+    /// **entry_size**: Defines the size of an entry (each entry have the exact same size), value vary depending of if this binary file is 32 or 64 bits
+    fn parse_section_header(instructions: &[u8], is_32bits: bool, header_location: u64, num_of_entries: u16, entry_size: u16) -> Result<Vec<SectionHeader>, ()> {
+        let mut sections: Vec<SectionHeader> = Default::default();
+        for i in 0..num_of_entries as u64 {
+            sections.push(Self::parse_section_entry(instructions, is_32bits, header_location + i * entry_size as u64)?);
+        }
+        Ok(sections)
+    }
+
+
+    /// Parse one entry of the section header
+    /// 
+    /// ## Parameters:
+    /// 
+    /// **instructions**: array of bytes of the binary file
+    /// **is_32bits**: contain whether the binary file is 32 bits or 64 bits
+    /// **location**: represent the position of the entry on the file image
+    fn parse_section_entry(instructions: &[u8], is_32bits: bool, location: u64) -> Result<SectionHeader, ()> {
+        SectionHeader::try_from((instructions, location, is_32bits))
+    }
+
+
+}
+
+/// return the memory address of something stored at address
+/// Can return None if the file is smaller than adress + 3 (or 7 if 64 bits), in this case, the elf header is incorrect
+fn get_address_point(instructions: &[u8], address: usize, is_32bits: bool) -> Option<u64> {
+    if is_32bits {
+        let mut bytes: [u8; 4] = [0; 4];
+        bytes[0] = instructions.get(address).copied()?;
+        bytes[1] = instructions.get(address + 1).copied()?;
+        bytes[2] = instructions.get(address + 2).copied()?;
+        bytes[3] = instructions.get(address + 3).copied()?;
+        Option::Some(u32::from_le_bytes(bytes) as u64)
+    } else {
+        let mut bytes: [u8; 8] = [0; 8];
+        bytes[0] = instructions.get(address).copied()?;
+        bytes[1] = instructions.get(address + 1).copied()?;
+        bytes[2] = instructions.get(address + 2).copied()?;
+        bytes[3] = instructions.get(address + 3).copied()?;
+        bytes[4] = instructions.get(address + 4).copied()?;
+        bytes[5] = instructions.get(address + 5).copied()?;
+        bytes[6] = instructions.get(address + 6).copied()?;
+        bytes[7] = instructions.get(address + 7).copied()?;
+        Option::Some(u64::from_le_bytes(bytes))
+    }
+}
+
+/// Tests has been made for C program compiled with RISC-V GCC 12.2.0, target: riscv64-unknown-elf
+/// 
+/// It may not pass in the future if future gcc version modify order of the binary or something else
+#[cfg(test)]
+mod test {
+    use crate::simulator::{loader::{Loader, SectionHeader}, machine::Machine};
+
+
+    #[test]
+    fn test_parse_elf() {
+        let mut machine = Machine::init_machine();
+        let loader = Loader::load_and_parse("./test/riscv_instructions/simple_arithmetics/unsigned_addition").expect("IO Error");
+        loader.load_into_machine(&mut machine, 0).expect("Parsing error");
+        assert!(!loader.elf_header.is_32bits);
+        assert!(!loader.elf_header.endianess);
+        assert!(loader.elf_header.sys_v_abi);
+        assert!(loader.elf_header.is_riscv_target);
+        assert_eq!(1, loader.elf_header.version);
+        assert_eq!(0x4000, loader.elf_header.entrypoint);
+        assert_eq!(64, loader.elf_header.elf_header_size);
+        assert_eq!(64, loader.elf_header.program_header_location);
+        assert_eq!(18984, loader.elf_header.section_header_location);
+        assert_eq!(56, loader.elf_header.program_header_size);
+        assert_eq!(64, loader.elf_header.section_header_size);
+        assert_eq!(4, loader.elf_header.program_header_entries);
+        assert_eq!(9, loader.elf_header.section_header_entries);
+        println!("{:#x?}", loader.sections);
+    }
+
+    #[test]
+    fn test_parse_section() {
+        let mut machine = Machine::init_machine();
+        let loader = Loader::load_and_parse("./test/riscv_instructions/simple_arithmetics/unsigned_addition").expect("IO Error");
+        loader.load_into_machine(&mut machine, 0).expect("Parsing error");
+        assert_eq!(9, loader.sections.len());
+        let n = loader.sections.iter().filter(|p| { p.does_flag_contains_key(crate::simulator::loader::FlagValue::ShfAlloc)}).collect::<Vec<&SectionHeader>>().len();
+        assert_eq!(3, n);
+        assert_eq!(loader.sections[1].virt_addr, 0x4000);
+        assert_eq!(loader.sections[1].image_offset, 0x1000);
+        assert!(loader.sections[1].does_flag_contains_key(crate::simulator::loader::FlagValue::ShfAlloc));
+        assert_eq!(loader.sections[2].virt_addr, 0x400_000); 
+        assert_eq!(loader.sections[2].image_offset, 0x2000);
+        assert!(loader.sections[2].does_flag_contains_key(crate::simulator::loader::FlagValue::ShfAlloc));
+    }
+
 }

src/simulator/machine.rs

@@ -177,7 +177,7 @@ impl Machine {
 	/// ### Parameters
 	/// 
 	///  - **machine** contains the memory
-	pub fn _extract_memory(&self){
+	pub fn _extract_memory(&mut self){
 		let file_path = "burritos_memory.txt";
 		let write_to_file = |path| -> std::io::Result<File> {
 			let mut file = File::create(path)?;
@@ -207,9 +207,9 @@ impl Machine {
 		}
 		println!("________________SP________________");
 		let sp_index = self.int_reg.get_reg(2);
-		for i in 0..5 {
+		/* for i in 0..5 {
 			println!("SP+{:<2} : {:16x}", i*8, self.read_memory(8, (sp_index + i*8) as usize));
-		}		
+		} */		
 		println!("##################################");
 	}
 
@@ -253,6 +253,7 @@ impl Machine {
 				Ok(MachineOk::Shutdown) => break,
 				Err(e) => { if e.to_string().contains("System") { break; } panic!("FATAL at pc {} -> {}", self.pc, e) }
 			}
+			self.write_int_register(0, 0); // In case an instruction write on register 0
 		}
 	}
 

test/Makefile

@@ -1,9 +1,15 @@
 TOPDIR=.
 include $(TOPDIR)/Makefile.config
 
+
+all: dumps user_lib tests
 # 
 # Main targets
 #
+
+build: user_lib
+	$(MAKE) build -C riscv_instructions/
+
 dumps:
 	$(MAKE) dumps -C riscv_instructions/
 	mkdir -p ${TOPDIR}/target/dumps/
@@ -18,4 +24,7 @@ tests: user_lib
 	find . -name '*.guac' -exec mv {} ${TOPDIR}/target/guac/ \;
 
 clean:
-	rm -rf $(TOPDIR)/target
+	$(MAKE) clean -C userlib/
+	$(MAKE) clean -C riscv_instructions/
+	$(RM) -rf $(TOPDIR)/target
+	

test/Makefile.tests

@@ -1,5 +1,11 @@
 include $(TOPDIR)/Makefile.config
+
 USERLIB = $(TOPDIR)/userlib
+
+AS = $(RISCV_AS) -c
+GCC = $(RISCV_GCC)
+LD = $(RISCV_LD)
+
 INCPATH += -I$(TOPDIR) -I$(USERLIB)
 LDFLAGS = $(RISCV_LDFLAGS) -T $(USERLIB)/ldscript.lds
 ASFLAGS = $(RISCV_ASFLAGS) $(INCPATH)
@@ -7,16 +13,16 @@ CFLAGS  = $(RISCV_CFLAGS) $(INCPATH)
 
 # Rules
 %.o: %.s
-	$(RISCV_AS) $(ASFLAGS) -c $<
+	$(AS) $(ASFLAGS) -c $<
 
 %.o: %.c
-	$(RISCV_GCC) $(CFLAGS) -c $<
+	$(GCC) $(CFLAGS) -c $<
 
 %.dump: %.o
 	$(RISCV_OBJCOPY) -j .text -O $(DUMP_FORMAT) $< $@
 
 %.guac: %.o
-	$(RISCV_LD) $(LDFLAGS) $+ -o $@
+	$(LD) $(LDFLAGS) $+ -o $@
 
 # Dependencies
 .%.d: %.s
@@ -31,6 +37,9 @@ CFLAGS  = $(RISCV_CFLAGS) $(INCPATH)
 		| sed '\''s/\($*\)\.o[ :]*/\1.o $@ : /g'\'' > $@; \
 		[ -s $@ ] || rm -f $@'
 
+$(PROGRAMS):
+	$(LD) $(LDFLAGS) $+ -o $@
+
 # Targets
 #clean:
 #	rm -rf *.o 2> /dev/null

test/riscv_instructions/.gitignore

@@ -0,0 +1,5 @@
+*
+!.gitignore
+!*.c
+!*.md
+!**/Makefile

test/riscv_instructions/Makefile

@@ -1,3 +1,8 @@
+build:
+	make build -C boolean_logic/
+	make build -C jump_instructions/
+	make build -C simple_arithmetics/
+
 dumps:
 	make dumps -C boolean_logic/
 	make dumps -C jump_instructions/
@@ -6,4 +11,9 @@ dumps:
 tests:
 	make tests -C boolean_logic/
 	make tests -C jump_instructions/
-	make tests -C simple_arithmetics/
+	make tests -C simple_arithmetics/
+
+clean:
+	$(MAKE) clean -C boolean_logic/
+	$(MAKE) clean -C jump_instructions/
+	$(MAKE) clean -C simple_arithmetics/

test/riscv_instructions/boolean_logic/Makefile

@@ -1,9 +1,17 @@
-TOPDIR = ../..
+
-include $(TOPDIR)/Makefile.tests
+PROGRAMS = comparisons if switch
+
+build: $(PROGRAMS)
 
 dumps: comparisons.dump if.dump switch.dump
 
 tests: comparisons.guac if.guac switch.guac
 
+TOPDIR = ../..
+include $(TOPDIR)/Makefile.tests
+
+clean:
+	$(RM) comparisons comparisons.o if if.o
+
 # Dependances
 $(PROGRAMS): % : $(USERLIB)/sys.o $(USERLIB)/libnachos.o %.o

test/riscv_instructions/jump_instructions/Makefile

@@ -1,6 +1,15 @@
-TOPDIR = ../..
+PROGRAMS = jump ret
-include $(TOPDIR)/Makefile.tests
+
+build: $(PROGRAMS)
 
 dumps: jump.dump ret.dump
 
-tests: jump.guac ret.guac
+tests: jump.guac ret.guac
+
+clean:
+	$(RM) jump jump.o ret ret.o
+
+TOPDIR = ../..
+include $(TOPDIR)/Makefile.tests
+
+$(PROGRAMS): % : $(USERLIB)/sys.o $(USERLIB)/libnachos.o %.o

test/riscv_instructions/simple_arithmetics/Makefile

@@ -1,6 +1,16 @@
-TOPDIR = ../..
+
-include $(TOPDIR)/Makefile.tests
+PROGRAMS = unsigned_addition unsigned_division unsigned_multiplication unsigned_substraction
+
+build: $(PROGRAMS)
 
 dumps: unsigned_addition.dump unsigned_division.dump unsigned_multiplication.dump unsigned_substraction.dump
 
-tests: unsigned_addition.guac unsigned_division.guac unsigned_multiplication.guac unsigned_substraction.guac
+tests: unsigned_addition.guac unsigned_division.guac unsigned_multiplication.guac unsigned_substraction.guac
+
+clean:
+	$(RM) unsigned_addition unsigned_addition.o unsigned_division unsigned_division.o unsigned_multiplication unsigned_multiplication.o unsigned_substraction unsigned_substraction.o
+
+TOPDIR = ../..
+include $(TOPDIR)/Makefile.tests
+
+$(PROGRAMS): % : $(USERLIB)/sys.o $(USERLIB)/libnachos.o %.o

test/userlib/Makefile

@@ -1,4 +1,7 @@
 TOPDIR = ../
 include $(TOPDIR)/Makefile.tests
 
-default: sys.o libnachos.o
+default: sys.o libnachos.o
+
+clean:
+	$(RM) libnachos.o sys.o

test/userlib/syscall.h

@@ -84,7 +84,7 @@
 typedef int t_error;
 
 /* Stop Nachos, and print out performance stats */
-void Halt();		
+void Shutdown();		
  
 
 /* Return the time spent running Nachos */