add function calls

common/src/lib.rs

@@ -5,6 +5,10 @@ use thiserror::Error;
 pub enum ExecutionError {
     #[error("Trying to access invalid memory location!")]
     InvalidMemoryLocation,
+    #[error("Stack Overflow")]
+    StackOverflow,
+    #[error("Stack Underflow")]
+    StackUnderflow,
 }
 
 #[derive(Debug)]

src/main.rs

@@ -30,30 +30,48 @@ fn main() -> anyhow::Result<()> {
                 .ok()
         })
         .unwrap_or_else(|| {
+            use Bytecode::*;
             vec![
-                Bytecode::Nop as u32,
+                /* 0 */ Jmp as u32,
-                Bytecode::Nop as u32,
+                /* 1 */ 15,
-                Bytecode::Nop as u32,
+                /* 2 */ Pop as u32,
-                Bytecode::Nop as u32,
+                /* 3 */ 5,
-                Bytecode::Set as u32,
+                /* 4 */ Pop as u32,
-                0x00,
+                /* 5 */ 0,
-                42,
+                /* 6 */ Pop as u32,
-                Bytecode::Set as u32,
+                /* 7 */ 1,
-                0x01,
+                /* 8 */ Add as u32,
-                10,
+                /* 9 */ 0,
-                Bytecode::Add as u32,
+                /* 10 */ 1,
-                0x00,
+                /* 11 */ PushReg as u32,
-                0x01,
+                /* 12 */ 5,
-                Bytecode::Store as u32,
+                /* 13 */ RetReg as u32,
-                0x40,
+                /* 14 */ 0,
-                0x00,
+                /* 15 */ Nop as u32,
-                Bytecode::Inspect as u32,
+                /* 16 */ Nop as u32,
-                0x40,
+                /* 17 */ Nop as u32,
-                0xFF,
+                /* 18 */ Nop as u32,
+                /* 19 */ PushValue as u32,
+                /* 20 */ 42,
+                /* 21 */ LoadValue as u32,
+                /* 22 */ 0,
+                /* 23 */ 10,
+                /* 24 */ PushReg as u32,
+                /* 25 */ 0,
+                /* 26 */ Call as u32,
+                /* 27 */ 2,
+                /* 28 */ Pop as u32,
+                /* 29 */ 3,
+                /* 30 */ Store as u32,
+                /* 31 */ 40,
+                /* 32 */ 3,
+                /* 33 */ Inspect as u32,
+                /* 34 */ 40,
+                /* 35 */ Halt as u32,
             ]
         });
 
-    let mut cpu = NativeCpu::new(1024 * 1024, 4);
+    let mut cpu = NativeCpu::new(1024 * 1024, 6);
     cpu.set_verbose(verbose);
 
     cpu.load_memory(0, &memory);

src/native.rs

@@ -3,15 +3,22 @@ use num_derive::{FromPrimitive, ToPrimitive};
 use num_traits::FromPrimitive;
 
 #[derive(Debug, PartialEq, PartialOrd, Copy, Clone, Hash, Eq, Ord, FromPrimitive, ToPrimitive)]
-#[repr(usize)]
+#[repr(u32)]
 pub enum Bytecode {
     Nop = 0x00,
-    Set = 0x01,
+    LoadValue = 0x01,
-    Load = 0x02,
+    LoadMemory = 0x02,
     Store = 0x03,
-    Add = 0x12,
+    PushValue = 0x04,
+    PushReg = 0x05,
+    Pop = 0x06,
+    Add = 0x10,
+    Call = 0xF0,
+    Ret = 0xF1,
+    RetReg = 0xF2,
+    Jmp = 0xF3,
     Inspect = 0xFE,
-    Halt = 0xFF,
+    Halt = 0xFFFFFFFF,
 }
 
 #[derive(Debug)]
@@ -19,9 +26,8 @@ pub struct NativeCpu {
     memory: Vec<u32>,
     memory_score_multiplier: usize,
     registers: Vec<u32>,
-    pc: u32,              // Program counter
+    instruction_pointer: u32,
-    // sp: u32,              // Stack pointer
+    stack_pointer: u32, // Stack pointer
-    // call_stack: Vec<u32>, // Call stack for function calls
     verbose: bool,
     cycles: usize,              // Performance counter for cycles
     memory_access_score: usize, // Tracks the performance score
@@ -81,14 +87,13 @@ impl CpuTrait for NativeCpu {
 }
 
 impl NativeCpu {
-    pub fn new(memory: u64, registers: u8) -> Self {
+    pub fn new(memory_size: u32, registers: u8) -> Self {
         Self {
-            memory: vec![0; memory as usize],
+            memory: vec![0; memory_size as usize],
             memory_score_multiplier: 10,
             registers: vec![0; registers as usize],
-            pc: 0,
+            instruction_pointer: 0,
-            // sp: 1024 * 1024, // Stack grows downward
+            stack_pointer: memory_size - 1, // Stack starts at the top of memory
-            // call_stack: Vec::new(),
             verbose: false,
             cycles: 0,
             memory_access_score: 0,
@@ -107,17 +112,19 @@ impl NativeCpu {
     fn run(&mut self, cycles: isize) -> Result<CpuStats, ExecutionError> {
         let mut executed = 0;
 
-        while (cycles < 0 || executed < cycles) && (self.pc as usize) < self.memory.len() {
+        while (cycles < 0 || executed < cycles)
-            let opcode = self.read_memory(self.pc)?;
+            && (self.instruction_pointer as usize) < self.memory.len()
-            self.pc += 1;
+        {
+            let opcode = self.read_memory(self.instruction_pointer)?;
+            self.instruction_pointer += 1;
 
             match Bytecode::from_u32(opcode) {
-                Some(Bytecode::Set) => {
+                Some(Bytecode::LoadValue) => {
-                    let reg = self.read_memory(self.pc)?;
+                    let reg = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
-                    let imm = self.read_memory(self.pc)?;
+                    let imm = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
                     if self.verbose {
                         println!("SET R{}, {}", reg, imm);
@@ -126,12 +133,12 @@ impl NativeCpu {
                     self.registers[reg as usize] = imm;
                     self.cycles += 2;
                 }
-                Some(Bytecode::Load) => {
+                Some(Bytecode::LoadMemory) => {
-                    let reg = self.read_memory(self.pc)?;
+                    let reg = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
-                    let addr = self.read_memory(self.pc)?;
+                    let addr = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
                     if self.verbose {
                         println!("LOAD R{}, @{:#02x}", reg, addr);
@@ -141,11 +148,11 @@ impl NativeCpu {
                     self.cycles += 2;
                 }
                 Some(Bytecode::Store) => {
-                    let addr = self.read_memory(self.pc)?;
+                    let addr = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
-                    let reg = self.read_memory(self.pc)?;
+                    let reg = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
                     if self.verbose {
                         println!("STORE @{:#02x}, R{}", addr, reg);
@@ -155,17 +162,17 @@ impl NativeCpu {
                     self.cycles += 2;
                 }
                 Some(Bytecode::Inspect) => {
-                    let addr = self.read_memory(self.pc)?;
+                    let addr = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
                     println!("INSPECT @{:#02x} = {}", addr, self.read_memory(addr)?);
                 }
                 Some(Bytecode::Add) => {
-                    let reg1 = self.read_memory(self.pc)?;
+                    let reg1 = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
-                    let reg2 = self.read_memory(self.pc)?;
+                    let reg2 = self.read_memory(self.instruction_pointer)?;
-                    self.pc += 1;
+                    self.instruction_pointer += 1;
 
                     if self.verbose {
                         println!(
@@ -181,6 +188,97 @@ impl NativeCpu {
                         self.registers[reg1 as usize].wrapping_add(self.registers[reg2 as usize]);
                     self.cycles += 1;
                 }
+                Some(Bytecode::Jmp) => {
+                    let imm = self.read_memory(self.instruction_pointer)?;
+                    self.instruction_pointer = imm;
+
+                    if self.verbose {
+                        println!("JMP {}", imm);
+                    }
+
+                    self.cycles += 2;
+                }
+                Some(Bytecode::PushValue) => {
+                    let imm = self.read_memory(self.instruction_pointer)?;
+                    self.instruction_pointer += 1;
+
+                    if self.verbose {
+                        println!("PUSH {}", imm);
+                    }
+
+                    self.push_stack(imm)?;
+
+                    self.cycles += 2;
+                }
+                Some(Bytecode::PushReg) => {
+                    let reg = self.read_memory(self.instruction_pointer)?;
+                    self.instruction_pointer += 1;
+
+                    let val = self.registers[reg as usize];
+
+                    if self.verbose {
+                        println!("PUSH R{}", reg);
+                    }
+
+                    self.push_stack(val)?;
+
+                    self.cycles += 2;
+                }
+                Some(Bytecode::Pop) => {
+                    let reg = self.read_memory(self.instruction_pointer)?;
+                    self.instruction_pointer += 1;
+
+                    if self.verbose {
+                        println!("POP R{}", reg);
+                    }
+
+                    self.registers[reg as usize] = self.pop_stack()?;
+
+                    self.cycles += 2;
+                }
+                Some(Bytecode::Call) => {
+                    let target = self.read_memory(self.instruction_pointer)?;
+                    self.instruction_pointer += 1;
+
+                    if self.verbose {
+                        println!("CALL @{:#02x}", target);
+                    }
+
+                    // Push the current PC onto the stack as the return address
+                    self.push_stack(self.instruction_pointer)?;
+
+                    // Jump to the target address
+                    self.instruction_pointer = target;
+
+                    self.cycles += 3; // CALL takes 3 cycles
+                }
+                Some(Bytecode::RetReg) => {
+                    let reg = self.read_memory(self.instruction_pointer)?;
+                    self.instruction_pointer += 1;
+
+                    // Pop the return address from the stack
+                    let return_address = self.pop_stack()?;
+
+                    if self.verbose {
+                        println!("RET R{} to @{:#02x}", reg, return_address);
+                    }
+
+                    self.push_stack(self.registers[reg as usize])?;
+
+                    self.instruction_pointer = return_address;
+                    self.cycles += 2; // RET takes 2 cycles
+                }
+                Some(Bytecode::Ret) => {
+                    // Pop the return address from the stack
+                    let return_address = self.pop_stack()?;
+
+                    if self.verbose {
+                        println!("RET to @{:#02x}", return_address);
+                    }
+
+                    self.instruction_pointer = return_address;
+                    self.cycles += 2; // RET takes 2 cycles
+                }
                 Some(Bytecode::Halt) => {
                     if self.verbose {
                         println!("HALT");
@@ -237,30 +335,22 @@ impl NativeCpu {
         Ok(())
     }
 
-    // fn push_to_stack(&mut self, value: u32) -> Result<(), ExecutionError> {
+    fn push_stack(&mut self, value: u32) -> Result<(), ExecutionError> {
-    //     self.valid_address(self.sp)?;
+        if self.stack_pointer == 0 {
-    //     self.sp -= 1;
+            return Err(ExecutionError::StackOverflow);
-    //     self.memory[self.sp as usize] = value;
+        }
-    //     Ok(())
+
-    // }
+        self.memory[self.stack_pointer as usize] = value;
-
+        self.stack_pointer -= 1;
-    // fn pop_from_stack(&mut self) -> Result<u32, ExecutionError> {
+        Ok(())
-    //     self.valid_address(self.sp)?;
+    }
-    //     let value = self.memory[self.sp as usize];
+
-    //     self.sp += 1;
+    fn pop_stack(&mut self) -> Result<u32, ExecutionError> {
-    //     Ok(value)
+        if self.stack_pointer as usize >= self.memory.len() - 1 {
-    // }
+            return Err(ExecutionError::StackUnderflow);
-
+        }
-    // fn call_function(&mut self, function_address: u32) {
+
-    //     self.call_stack.push(self.pc); // Save current PC to call stack
+        self.stack_pointer += 1;
-    //     self.pc = function_address; // Jump to the function's address
+        Ok(self.memory[self.stack_pointer as usize])
-    // }
+    }
-
-    // fn return_from_function(&mut self) {
-    //     if let Some(return_address) = self.call_stack.pop() {
-    //         self.pc = return_address; // Restore PC from the call stack
-    //     } else {
-    //         panic!("Call stack underflow: No return address");
-    //     }
-    // }
 }