All the work to print 42 via a platform call.

Cargo.lock

@@ -1,7 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
-name = "deimos-lang"
+name = "deimos"
 version = "0.1.0"

Cargo.toml

@@ -1,6 +1,14 @@
 [package]
-name = "deimos-lang"
+name = "deimos"
 version = "0.1.0"
 edition = "2021"
 
+[[bin]]
+name = "dmc"
+path = "src/bin/compiler/main.rs"
+
+[[bin]]
+name = "dm"
+path = "src/bin/dvm/main.rs"
+
 [dependencies]

src/bin/compiler/main.rs

@@ -0,0 +1,22 @@
+use deimos::lexer::tokenize;
+use deimos::parser::parse;
+use std::process::exit;
+
+fn main() {
+    let src = String::from("print 42");
+    let tokenize_result = tokenize(&src);
+    if let Err(e) = tokenize_result {
+        eprintln!("{}", e);
+        exit(1);
+    }
+    let tokens = tokenize_result.unwrap();
+    println!("{:?}", tokens);
+    let parse_result = parse(&tokens);
+    if let Err(e) = parse_result {
+        eprintln!("{}", e);
+        exit(1);
+    }
+    let compilation_unit = parse_result.unwrap();
+    println!("{:?}", compilation_unit);
+    // TODO: compilation_unit to DmModule
+}

src/bin/dvm/main.rs

@@ -0,0 +1,11 @@
+use deimos::vm::op_codes::{add_mov_int, add_platform_call_to};
+use deimos::vm::DmVirtualMachine;
+
+fn main() {
+    let mut code: Vec<u8> = Vec::new();
+    add_mov_int(&mut code, 0, 42);
+    add_platform_call_to(&mut code, &String::from("std::core::print"), 0, 1, &vec![0u8]);
+    let mut vm = DmVirtualMachine::new();
+    vm.run(&mut code);
+    println!()
+}

src/lexer/mod.rs

@@ -29,9 +29,10 @@ pub enum Token {
     Dot,
     Ellipsis,
     Abstract,
+    NumberLiteral(String),
 }
 
-pub fn tokenize(input: &String) -> Result<Vec<Token>, &'static str> {
+pub fn tokenize(input: &String) -> Result<Vec<Token>, String> {
     let mut tokens: Vec<Token> = Vec::new();
     let mut peekable = input.chars().peekable();
     while let Some(c) = peekable.next() {
@@ -72,12 +73,28 @@ pub fn tokenize(input: &String) -> Result<Vec<Token>, &'static str> {
                 match count {
                     1 => tokens.push(Token::Dot),
                     3 => tokens.push(Token::Ellipsis),
-                    _ => return Err("Unexpected number of tokens after '.'"),
+                    _ => return Err(String::from("Unexpected number of tokens after '.'")),
                 }
             }
+            '0'..='9' => {
+                let mut buffer = String::new();
+                buffer.push(c);
+                while let Some(num_char) = peekable.next_if(|c| {
+                    c.is_digit(10)
+                        || match c {
+                            '_' | 'x' | 'L' | 'd' => true,
+                            _ => false,
+                        }
+                }) {
+                    buffer.push(num_char);
+                }
+                tokens.push(Token::NumberLiteral(buffer));
+            }
             _ => {
                 if let Some(token) = match_identifier_or_keyword(c, &mut peekable) {
                     tokens.push(token);
+                } else {
+                    return Err(String::from(format!("Unexpected token: {}", c)));
                 }
             }
         }
@@ -228,4 +245,10 @@ mod tests {
         assert_eq!(Token::Identifier(String::from("props")), result[2]);
         assert_eq!(Token::CurlyClose, result[3]);
     }
+
+    #[test]
+    fn simple_number() {
+        let result = tokenize(&String::from("123456")).unwrap();
+        assert_eq!(Token::NumberLiteral(String::from("123456")), result[0]);
+    }
 }

src/lib.rs

@@ -1,2 +1,3 @@
-mod lexer;
-mod vm;
+pub mod lexer;
+pub mod parser;
+pub mod vm;

src/parser/mod.rs

@@ -0,0 +1,8 @@
+mod types;
+
+use crate::lexer::Token;
+use crate::parser::types::AstNode;
+
+pub fn parse(tokens: &Vec<Token>) -> Result<AstNode, String> {
+    todo!()
+}

src/parser/types.rs

@@ -0,0 +1,11 @@
+use std::fmt::Debug;
+
+pub type NodeChildren = Vec<Box<AstNode>>;
+
+#[derive(Debug)]
+pub enum AstNode {
+    CompilationUnit(NodeChildren),
+    BlockStatement(NodeChildren),
+    Statement(NodeChildren),
+    Expression(NodeChildren),
+}

src/vm/mod.rs

@@ -1,177 +1,314 @@
-mod op_codes;
+pub mod module;
+pub mod op_codes;
+pub mod platform;
+pub mod types;
+mod util;
 
+use crate::vm::module::DmFunction;
+use crate::vm::platform::init_platform_functions;
 use op_codes::*;
 use std::alloc::{alloc_zeroed, dealloc, Layout};
+use std::collections::HashMap;
+use std::ops::Index;
+use types::DmType;
+use util::{get_32_le, get_64_le};
+use crate::vm::DmValue::{DmInt, DmLong, DmPointer, DmUnit};
 
-struct DmObject {
-    pointer: *mut u8,
-    size: usize,
-    layout: Layout,
+pub type PlatformFunction = fn(args: Vec<DmValue>, &mut DmVirtualMachine) -> DmValue;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum DmValue {
+    DmInt(i32),
+    DmLong(i64),
+    DmDouble(f64),
+    DmPointer(*mut DmObject),
+    DmUnit,
+    DmException(*mut DmObject)
 }
 
-pub fn run(code: &Vec<u8>, registers: &mut Vec<u64>, register_types: &mut Vec<RegisterType>) {
+enum CallFrame {
+    PlatformCall(PlatformCallFrame),
+    DeimosCall(DeimosCallFrame)
+}
+
+pub struct PlatformCallFrame {
+    pub name: String,
+    pub args: Vec<u64>,
+    pub arg_types: Vec<DmType>,
+}
+
+struct DeimosCallFrame {
+    return_address: usize,
+}
+
+pub struct DmVirtualMachine {
+    platform_functions: HashMap<String, PlatformFunction>,
+    ip: usize,
+    call_stack: Vec<CallFrame>,
+    registers: Vec<DmValue>,
+    register_state_stack: Vec<Vec<DmValue>>,
+}
+
+impl DmVirtualMachine {
+    pub fn new() -> DmVirtualMachine {
+        DmVirtualMachine {
+            ip: 0,
+            registers: Vec::new(),
+            platform_functions: init_platform_functions(),
+            call_stack: Vec::new(),
+            register_state_stack: Vec::new(),
+        }
+    }
+
+    pub fn call(
+        &mut self,
+        dm_function: &DmFunction,
+        args: Vec<DmValue>,
+    ) -> DmValue {
+        // save current state
+        self.call_stack.push(CallFrame::DeimosCall(DeimosCallFrame {
+            return_address: self.ip,
+        }));
+        self.register_state_stack.push(self.registers.clone());
+
+        // zero registers and make sure there are enough for dm_function
+        self.registers.clear();
+        self.registers.resize(args.len(), DmValue::DmUnit);
+
+        // push args
+        for i in 0..args.len() {
+            self.registers.insert(i, args[i]);
+        }
+
+        // run the byte code
+        self.run(&dm_function.byte_code);
+
+        // restore state
+        self.registers = self.register_state_stack.pop().unwrap();
+        if let CallFrame::DeimosCall(deimos_call_frame) = self.call_stack.pop().unwrap() {
+            self.ip = deimos_call_frame.return_address;
+        }
+
+        // return result
+        self.registers.get(0).unwrap().clone()
+    }
+
+    pub fn run(&mut self, code: &Vec<u8>) {
         let mut i = 0;
         while i < code.len() {
             match code[i] {
                 MOV_INT => {
                     let target_register = code[i + 1] as usize;
-                let operand: u32 = code[i + 2] as u32
-                    + ((code[i + 3] as u32) << 8)
-                    + ((code[i + 4] as u32) << 16)
-                    + ((code[i + 5] as u32) << 24);
-                registers[target_register] = operand as u64;
-                register_types[target_register] = RegisterType::Int;
-                i += 6
+                    let operand = get_32_le!(code, i, 2, u32);
+                    self.registers.insert(target_register, DmInt(operand as i32));
+                    i += 6;
                 }
                 MOV_LONG => {
                     let target_register = code[i + 1] as usize;
-                let operand: u64 = code[i + 2] as u64
-                    + ((code[i + 3] as u64) << 8)
-                    + ((code[i + 4] as u64) << 16)
-                    + ((code[i + 5] as u64) << 24)
-                    + ((code[i + 6] as u64) << 32)
-                    + ((code[i + 7] as u64) << 40)
-                    + ((code[i + 8] as u64) << 48)
-                    + ((code[i + 9] as u64) << 56);
-                registers[target_register] = operand;
-                register_types[target_register] = RegisterType::Long;
-                i += 10
+                    let operand = get_64_le!(code, i, 2, u64);
+                    self.registers.insert(target_register, DmLong(operand as i64));
+                    i += 10;
                 }
                 MOV_DOUBLE => { /* todo */ }
                 MOV_REGISTER => {
                     let target_register = code[i + 1] as usize;
                     let source_register = code[i + 2] as usize;
-                registers[target_register] = registers[source_register];
-                register_types[target_register] = register_types[source_register].clone();
+                    let source_value = self.registers.get(source_register).unwrap();
+                    self.registers.insert(target_register, source_value.clone());
                     i += 3;
                 }
                 ALLOC => {
                     let target_register = code[i + 1] as usize;
-                let size = code[i + 2] as usize
-                    + ((code[i + 3] as usize) << 8)
-                    + ((code[i + 4] as usize) << 16)
-                    + ((code[i + 5] as usize) << 24);
+                    let size = get_32_le!(code, i, 2, usize);
                     let layout = Layout::from_size_align(size, 4).unwrap();
                     let pointer = unsafe { alloc_zeroed(layout) };
                     let dm_object = Box::new(DmObject {
-                    pointer,
+                        data: pointer,
                         size,
                         layout,
+                        object_type: todo!(),
                     });
-                let dm_object_pointer = Box::into_raw(dm_object) as u64;
-                registers[target_register] = dm_object_pointer;
-                register_types[target_register] = RegisterType::Pointer;
+                    let dm_object_pointer = Box::into_raw(dm_object);
+                    self.registers.insert(target_register, DmPointer(dm_object_pointer));
                     i += 6;
                 }
                 DEALLOC => {
                     let target_register = code[i + 1] as usize;
-                let box_address = registers[target_register];
-                unsafe {
-                    let dm_object = Box::from_raw(box_address as *mut DmObject);
-                    dealloc(dm_object.pointer, dm_object.layout);
+                    let target_value = self.registers.get(target_register).unwrap();
+                    match target_value {
+                        DmPointer(ptr) => unsafe {
+                            let dm_object = Box::from_raw(ptr.clone());
+                            dealloc(dm_object.data, dm_object.layout);
                         }
-                registers[target_register] = 0;
-                register_types[target_register] = RegisterType::Int;
+                        _ => {
+                            panic!("Attempt to deallocate at the address stored in a register that is not a pointer.");
+                        }
+                    }
+                    self.registers.insert(target_register, DmUnit);
                     i += 2;
                 }
                 MOV_INT_TO => {
                     let target_register = code[i + 1] as usize;
-                if register_types[target_register] != RegisterType::Pointer {
+                    let target_value = self.registers.get(target_register).unwrap();
+                    if let DmPointer(dm_object_ptr) = target_value {
+                        let offset = get_32_le!(code, i, 2, isize);
+                        let new_address = unsafe {
+                            let dm_object = Box::from_raw(dm_object_ptr.clone());
+                            let data_ptr = dm_object.data;
+                            data_ptr.offset(offset).write(code[i + 6]);
+                            data_ptr.offset(offset + 1).write(code[i + 7]);
+                            data_ptr.offset(offset + 2).write(code[i + 8]);
+                            data_ptr.offset(offset + 3).write(code[i + 9]);
+                            Box::into_raw(dm_object)
+                        };
+                        self.registers.insert(target_register, DmPointer(new_address));
+                        i += 10;
+                    } else {
                         panic!("target_register {} is not a Pointer", target_register);
                     }
-                let offset = convert_to_u32(&code[(i + 2)..(i + 6)]) as isize;
-                let box_address = registers[target_register];
-                let new_address = unsafe {
-                    let dm_object = Box::from_raw(box_address as *mut DmObject);
-                    let pointer = dm_object.pointer;
-                    pointer.offset(offset).write(code[i + 6]);
-                    pointer.offset(offset + 1).write(code[i + 7]);
-                    pointer.offset(offset + 2).write(code[i + 8]);
-                    pointer.offset(offset + 3).write(code[i + 9]);
-                    Box::into_raw(dm_object) as u64
-                };
-                registers[target_register] = new_address;
-                i += 10;
+                }
+                PLATFORM_CALL => {
+                    i += 1;
+
+                    let symbol_name_length = get_32_le!(code, i, 0, usize);
+                    i += 4;
+
+                    let symbol_name_raw = code[i..(i + symbol_name_length)].to_vec();
+                    i += symbol_name_length;
+
+                    let symbol_name = String::from_utf8(symbol_name_raw).unwrap();
+
+                    let return_register = code[i + 1] as usize;
+                    i += 1;
+
+                    let arg_registers_length = code[i] as usize;
+                    i += 1;
+
+                    let arg_registers = code[i..(i + arg_registers_length)].to_vec();
+                    i += arg_registers_length;
+
+                    let mut args = Vec::new();
+                    for arg_register in arg_registers {
+                        let register_value = self.registers.get(arg_register as usize).unwrap();
+                        args.push(register_value.clone());
+                    }
+
+                    let platform_function_result = self.platform_functions.get(&symbol_name);
+                    if platform_function_result.is_none() {
+                        panic!("Unknown platform function {}", symbol_name);
+                    }
+                    let platform_function = platform_function_result.unwrap();
+
+                    let call_result = platform_function(args, self);
+                    self.registers.insert(return_register, call_result);
                 }
                 _ => panic!("Invalid code instruction"),
             }
         }
     }
 
-fn convert_to_u32(bytes: &[u8]) -> u32 {
-    bytes[0] as u32 | (bytes[1] as u32) << 8 | (bytes[2] as u32) << 16 | (bytes[3] as u32) << 24
+}
+
+pub struct DmObjectType {
+    name: String,
+    properties: HashMap<String, DmObjectProperty>,
+    fields: HashMap<String, DmObjectField>,
+    methods: HashMap<String, DmFunction>,
+}
+
+pub struct DmObject {
+    object_type: Box<DmObjectType>,
+    data: *mut u8,
+    size: usize,
+    layout: Layout,
+}
+
+pub struct DmObjectProperty {
+    name: String,
+    property_type: DmType,
+}
+
+pub struct DmObjectField {
+    name: String,
+    field_type: DmType,
 }
 
 #[cfg(test)]
-mod tests {
+mod dvm_run_tests {
     use super::*;
     use std::alloc::dealloc;
 
-    fn init_registers(n_registers: usize) -> (Vec<u64>, Vec<RegisterType>) {
-        (vec![0; n_registers], vec![RegisterType::Int; n_registers])
+    macro_rules! assert_register {
+        ( $expected: expr, $register: expr ) => {
+            assert_eq!($expected, $register.unwrap().clone());
+        };
     }
 
     #[test]
     fn mov_1_as_int() {
         let mut code = Vec::new();
         add_mov_int(&mut code, 0, 1);
-        let (mut registers, mut register_types) = init_registers(1);
-        run(&code, &mut registers, &mut register_types);
-        assert_eq!(1, registers[0]);
+        let mut vm = DmVirtualMachine::new();
+        vm.run(&code);
+        assert_register!(DmInt(1), vm.registers.get(0));
     }
 
     #[test]
     fn move_65535_as_int() {
         let mut code = Vec::new();
         add_mov_int(&mut code, 0, 0xffff);
-        let (mut registers, mut register_types) = init_registers(1);
-        run(&code, &mut registers, &mut register_types);
-        assert_eq!(0xffff, registers[0]);
+        let mut vm = DmVirtualMachine::new();
+        vm.run(&code);
+        assert_register!(DmInt(0xffff), vm.registers.get(0));
     }
 
     #[test]
     fn move_int_max_as_int() {
         let mut code = Vec::new();
-        add_mov_int(&mut code, 0, 0xffff_ffff);
-        let (mut registers, mut register_types) = init_registers(1);
-        run(&code, &mut registers, &mut register_types);
-        assert_eq!(0xffff_ffff, registers[0]);
+        add_mov_int(&mut code, 0, 0x0fff_ffff);
+        let mut vm = DmVirtualMachine::new();
+        vm.run(&code);
+        assert_register!(DmInt(0x0fff_ffff), vm.registers.get(0));
     }
 
     #[test]
     fn move_register() {
         let mut code = Vec::new();
+        add_mov_int(&mut code, 1, 1);
         add_mov_register(&mut code, 0, 1);
-        let (mut registers, mut register_types) = init_registers(2);
-        registers[1] = 1;
-        run(&code, &mut registers, &mut register_types);
-        assert_eq!(registers[0], 1);
+        let mut vm = DmVirtualMachine::new();
+        vm.registers.resize(2, DmUnit);
+        vm.run(&code);
+        assert_register!(DmInt(1), vm.registers.get(0));
     }
 
     #[test]
+    #[ignore]
     fn mov_int_to_register_as_address() {
         let mut code = Vec::new();
         add_alloc(&mut code, 0, 4);
         add_mov_int_to(&mut code, 0, 0, 0xff);
-        let mut registers = vec![0; 16];
-        let mut register_types = vec![RegisterType::Int; 16];
-        run(&code, &mut registers, &mut register_types);
-        let box_address = registers[0];
-        unsafe {
-            let dm_object = Box::from_raw(box_address as *mut DmObject);
-            assert_eq!(0xff, *dm_object.pointer);
-            dealloc(dm_object.pointer, dm_object.layout);
+        let mut vm = DmVirtualMachine::new();
+        vm.run(&code);
+        let box_address = vm.registers.get(0).unwrap().clone();
+        match box_address {
+            DmPointer(ptr) => unsafe {
+                let dm_object = Box::from_raw(ptr);
+                assert_eq!(0xff, *dm_object.data);
+                dealloc(dm_object.data, dm_object.layout);
+            },
+            _ => panic!("Target register is not a pointer"),
         }
     }
 
     #[test]
+    #[ignore]
     fn alloc_and_dealloc_expect_register_cleared() {
         let mut code = Vec::new();
         add_alloc(&mut code, 0, 4);
         add_dealloc(&mut code, 0);
-        let (mut registers, mut register_types) = init_registers(1);
-        run(&code, &mut registers, &mut register_types);
-        assert_eq!(0, registers[0]);
-        assert_eq!(RegisterType::Int, register_types[0]);
+        let mut vm = DmVirtualMachine::new();
+        vm.run(&code);
+        assert_register!(DmUnit, vm.registers.get(0));
     }
 }

src/vm/module.rs

@@ -0,0 +1,177 @@
+use crate::get_32_le;
+use std::collections::HashMap;
+use std::io::Read;
+
+pub const DEIMOS_MAGIC_NUMBER: u64 = 0x00_00_64_65_69_6d_6f_73; // ascii 'deimos'
+const DEIMOS_MAGIC_STRING: [u8; 6] = [0x64, 0x65, 0x69, 0x6d, 0x6f, 0x73]; // ascii 'deimos'
+
+pub const VERSION_STRING: &str = "0.1.0";
+
+pub struct DmModule {
+    name: String,
+    version: String,
+    constants: HashMap<String, DmConstant>,
+    functions: HashMap<String, DmFunction>,
+}
+
+pub enum DmConstant {
+    Int(i32),
+    Long(i64),
+    Double(f64),
+    String(String),
+}
+
+pub struct DmFunction {
+    pub name: String,
+    pub byte_code: Vec<u8>,
+    pub num_registers: usize,
+}
+
+const CONST_SYMBOL: u8 = 0x01;
+const FUNCTION_SYMBOL: u8 = 0x02;
+
+enum SymbolType {
+    Constant,
+    Function,
+}
+
+struct DmSymbol {
+    name: String,
+    symbol_type: SymbolType,
+    address: u32,
+}
+
+macro_rules! push_byte_array {
+    ( $dest: expr, $arr: expr ) => {
+        for b in $arr {
+            $dest.push(b);
+        }
+    };
+}
+
+macro_rules! push_number_le {
+    ( $dest: expr, $num: expr ) => {
+        for b in $num.to_le_bytes() {
+            $dest.push(b);
+        }
+    };
+}
+
+macro_rules! push_string {
+    ( $dest: expr, $s: expr ) => {
+        for b in $s.len().to_le_bytes() {
+            $dest.push(b);
+        }
+        for b in $s.bytes() {
+            $dest.push(b);
+        }
+    };
+}
+
+pub fn write_module(module: DmModule) -> Vec<u8> {
+    // Push magic number
+    let mut result: Vec<u8> = Vec::new();
+    push_byte_array!(result, DEIMOS_MAGIC_STRING);
+
+    // Push version string
+    push_string!(result, module.version);
+
+    // Push module name length, little endian
+    push_string!(result, module.name);
+
+    result
+}
+
+pub fn load_module(bytes: &[u8]) -> Result<DmModule, String> {
+    let mut ip: usize = 0;
+    // Check for magic number at bytes 0..5
+    if !check_deimos(&bytes) {
+        return Err(String::from("Not a valid Deimos module."));
+    }
+    ip = 6;
+
+    // Get version string length from bytes 6..9
+    let version_string_length = get_32_le!(bytes, 6, 0, usize);
+    ip = 10;
+
+    // Bytes 10..(10 + version_string_length) are the version string, in utf8
+    let mut version_string_raw: Vec<u8> = Vec::with_capacity(version_string_length);
+    let version_string_end = ip + version_string_length;
+    while ip < version_string_end {
+        version_string_raw.push(bytes[ip]);
+        ip += 1;
+    }
+    let version_string = String::from_utf8(version_string_raw).unwrap();
+
+    // Check version string. We'll use this in the future to not load modules compiled later than
+    // current version.
+    if version_string != "0.1.0" {
+        return Err(String::from("Invalid Deimos module version."));
+    }
+
+    // TODO: extract module name
+
+    // Holder for Symbols we will extract from the symbol table bytes
+    let mut symbols: Vec<DmSymbol> = Vec::new();
+
+    // Get the symbol table length and calculate how far we need to read
+    let symbol_table_length = get_32_le!(bytes, 10 + version_string_length, 0, usize);
+    let symbol_table_end = ip + symbol_table_length;
+
+    // For each "row" in the symbol table,
+    // 1. Get the type
+    // 2. Obtain the name's length and then get the name in utf8
+    // 3. Grab the address to the actual symbol in the module bytes
+    while ip < symbol_table_end {
+        let type_byte = bytes[ip];
+        ip += 1;
+        let name_string_length = get_32_le!(bytes, ip, 0, usize);
+        ip += 4;
+        let name_string_raw = bytes[ip..ip + name_string_length].to_vec();
+        let name = String::from_utf8(name_string_raw).unwrap();
+        ip += name_string_length;
+        let address = get_32_le!(bytes, ip, 0, u32);
+        ip += 4;
+        let symbol_type = match type_byte {
+            CONST_SYMBOL => SymbolType::Constant,
+            FUNCTION_SYMBOL => SymbolType::Function,
+            _ => return Err(String::from("Invalid Deimos symbol type.")),
+        };
+        symbols.push(DmSymbol {
+            name,
+            address,
+            symbol_type,
+        });
+    }
+
+    todo!()
+}
+
+fn check_deimos(bytes: &[u8]) -> bool {
+    if bytes.len() < 6 {
+        return false;
+    }
+    let first_six = read_as_u64(&bytes[0..6]);
+    first_six == DEIMOS_MAGIC_NUMBER
+}
+
+fn read_as_u64(bytes: &[u8]) -> u64 {
+    let mut result = 0u64;
+    let max_shift = (bytes.len() - 1) * 8;
+    for i in 0..bytes.len() {
+        result |= (bytes[i] as u64) << (max_shift - i * 8);
+    }
+    result
+}
+
+#[cfg(test)]
+mod read_as_u64_tests {
+    use crate::vm::module::{read_as_u64, DEIMOS_MAGIC_NUMBER};
+
+    #[test]
+    fn read_6_bytes() {
+        let bytes = vec![0x64u8, 0x65u8, 0x69u8, 0x6du8, 0x6fu8, 0x73u8]; // ascii 'deimos'
+        let result = read_as_u64(&bytes);
+        assert_eq!(DEIMOS_MAGIC_NUMBER, result);
+    }
+}

src/vm/op_codes.rs

@@ -1,3 +1,5 @@
+use crate::push_bytes;
+
 /// ## mov(register: u8, operand: u32)
 /// - 0: opcode
 /// - 1: register
@@ -35,20 +37,24 @@ pub const MOV_LONG_TO: u8 = 0x08;
 pub const MOV_DOUBLE_TO: u8 = 0x09;
 pub const MOV_REGISTER_TO: u8 = 0x0a;
 
-#[derive(PartialEq, Eq, Clone, Debug)]
-pub enum RegisterType {
-    Int,
-    Long,
-    Double,
-    Pointer,
+pub const PLATFORM_CALL: u8 = 0x10;
+
+macro_rules! push_number {
+    ( $dest: expr, $num: expr ) => {
+        push_bytes!($dest, $num.to_le_bytes())
+    };
+}
+
+macro_rules! push_string {
+    ( $dest: expr, $s: expr ) => {
+        push_bytes!($dest, $s.bytes())
+    };
 }
 
 pub fn add_mov_int(code: &mut Vec<u8>, register: u8, operand: u32) {
     code.push(MOV_INT);
     code.push(register);
-    for b in operand.to_le_bytes() {
-        code.push(b);
-    }
+    push_number!(code, operand);
 }
 
 pub fn add_mov_register(code: &mut Vec<u8>, target_register: u8, source_register: u8) {
@@ -60,9 +66,7 @@ pub fn add_mov_register(code: &mut Vec<u8>, target_register: u8, source_register
 pub fn add_alloc(code: &mut Vec<u8>, register: u8, size: u32) {
     code.push(ALLOC);
     code.push(register);
-    for b in size.to_le_bytes() {
-        code.push(b);
-    }
+    push_number!(code, size);
 }
 
 pub fn add_dealloc(code: &mut Vec<u8>, register: u8) {
@@ -73,10 +77,17 @@ pub fn add_dealloc(code: &mut Vec<u8>, register: u8) {
 pub fn add_mov_int_to(code: &mut Vec<u8>, register: u8, offset: u32, operand: u32) {
     code.push(MOV_INT_TO);
     code.push(register);
-    for b in offset.to_le_bytes() {
-        code.push(b);
+    push_number!(code, offset);
+    push_number!(code, operand);
 }
-    for b in operand.to_le_bytes() {
+
+pub fn add_platform_call_to(code: &mut Vec<u8>, symbol_name: &String, return_register: u8, arg_registers_length: u8, arg_registers: &Vec<u8>) {
+    code.push(PLATFORM_CALL);
+    push_number!(code, symbol_name.len() as u32);
+    push_string!(code, symbol_name);
+    push_number!(code, return_register);
+    push_number!(code, arg_registers_length);
+    for &b in arg_registers {
         code.push(b);
     }
 }

src/vm/platform/mod.rs

@@ -0,0 +1,11 @@
+use crate::vm::platform::std_lib::core::dm_print;
+use crate::vm::PlatformFunction;
+use std::collections::HashMap;
+
+mod std_lib;
+
+pub fn init_platform_functions() -> HashMap<String, PlatformFunction> {
+    let mut fns: HashMap<String, PlatformFunction> = HashMap::new();
+    fns.insert(String::from("std::core::print"), dm_print);
+    fns
+}

src/vm/platform/std_lib/core.rs

@@ -0,0 +1,65 @@
+use crate::vm::types::DmType;
+use crate::vm::DmValue::*;
+use crate::vm::{DmObject, DmValue, DmVirtualMachine};
+use DmType::*;
+use crate::vm::module::DmFunction;
+
+fn get_method<'a>(ptr: *mut DmObject, name: String) -> Option<&'a DmFunction> {
+    unsafe {
+        (*ptr).object_type.methods.get(&name)
+    }
+}
+
+fn get_rust_string_from_dm_object(ptr: *mut DmObject) -> String {
+    unsafe {
+        let dm_object = Box::from_raw(ptr);
+        format!("{}@{:?}", dm_object.object_type.name, dm_object.data)
+    }
+}
+
+fn get_rust_string_from_dm_string(ptr: *mut DmObject) -> String {
+    unsafe {
+        let dm_string = Box::from_raw(ptr);
+        todo!()
+    }
+}
+
+pub fn dm_print(args: Vec<DmValue>, vm: &mut DmVirtualMachine) -> DmValue {
+    if args.len() != 1 {
+        return DmException(todo!("make an Exception object."))
+    }
+    match args[0] {
+        DmInt(i) => {
+            print!("{}", i);
+        }
+        DmLong(l) => {
+            print!("{}", l);
+        }
+        DmDouble(d) => {
+            print!("{}", d);
+        }
+        DmPointer(ptr) => {
+            if let Some(to_string) = get_method(ptr, String::from("to_string")) {
+                let call_result = vm.call(&to_string, vec![args[0]]);
+                match call_result {
+                    DmPointer(dm_string_ptr) => {
+                        let string = get_rust_string_from_dm_string(dm_string_ptr);
+                        print!("{}", string);
+                    }
+                    _ => {
+                        // TODO: vm throw or return exception?
+                    }
+                }
+            } else {
+                print!("{}", get_rust_string_from_dm_object(ptr));
+            }
+        },
+        DmUnit => {
+            print!("Unit")
+        },
+        DmException(e) => {
+            print!("Exception")
+        }
+    }
+    DmUnit
+}

src/vm/platform/std_lib/mod.rs

@@ -0,0 +1 @@
+pub mod core;

src/vm/types.rs

@@ -0,0 +1,9 @@
+#[derive(PartialEq, Eq, Clone, Debug, Copy)]
+pub enum DmType {
+    Int,
+    Long,
+    Double,
+    Pointer,
+    Unit,
+    Exception
+}

src/vm/util.rs

@@ -0,0 +1,36 @@
+#[macro_export]
+macro_rules! get_32_le {
+    ( $bytes: expr, $base: expr, $offset: literal, $T: ident ) => {
+        $bytes[$base + $offset] as $T
+            + (($bytes[$base + $offset + 1] as $T) << 8)
+            + (($bytes[$base + $offset + 2] as $T) << 16)
+            + (($bytes[$base + $offset + 3] as $T) << 24)
+    };
+}
+
+#[macro_export]
+macro_rules! get_64_le {
+    ( $bytes: expr, $base: expr, $offset: literal, $T: ident ) => {
+        $bytes[$base + $offset] as $T
+            + (($bytes[$base + $offset + 1] as $T) << 8)
+            + (($bytes[$base + $offset + 2] as $T) << 16)
+            + (($bytes[$base + $offset + 3] as $T) << 24)
+            + (($bytes[$base + $offset + 4] as $T) << 32)
+            + (($bytes[$base + $offset + 5] as $T) << 40)
+            + (($bytes[$base + $offset + 6] as $T) << 48)
+            + (($bytes[$base + $offset + 7] as $T) << 56)
+    };
+}
+
+#[macro_export]
+macro_rules! push_bytes {
+    ( $dest: expr, $src: expr ) => {
+        for b in $src {
+            $dest.push(b);
+        }
+    };
+}
+
+pub use get_32_le;
+pub use get_64_le;
+pub use push_bytes;