mob

README.md

@@ -60,6 +60,12 @@ A location is a location in the VM code. It must contain a symbol with the label
 
 Mov moves the `value` `B` to the `place` `A`.
 
+### Movb
+
+`movb A, B`
+
+Mov moves the `value` `B` to the `place` `A`. Only a single byte is written.
+
 ### Add
 
 `add A, B`
@@ -131,5 +137,5 @@ The interrupt 0 exits the program. The exit code is passed in `r0`.
 ### `int 1`
 
 The interrupt 0 writes a string to standard output. `r0` contains the address of the string data.
-`r1` contains the length of the string. The string is encoded as `UTF-8`. After the interrupt completed,
-`r0` will contain a 0 if writing was successful, or a `1` if it failed.
+`r1` contains the length of the string. The string is forwarded as raw bytes to the OS.
+After the interrupt completed, `r0` will contain a 0 if writing was successful, or a `1` if it failed.

src/interpret.rs

@@ -9,6 +9,8 @@
 //! Decimal 1
 //! ```
 
+use std::io::Write;
+
 use logos::Span;
 
 use crate::{
@@ -33,8 +35,8 @@ struct InterpretCtx {
 
 impl InterpretCtx {
     fn interpret(&mut self, stmts: Vec<Stmt>) -> Result<()> {
-        let stmt_i = self.ip;
-        while stmt_i < stmts.len() {
+        while self.ip < stmts.len() {
+            let stmt_i = self.ip;
             self.ip += 1;
             self.interpret_stmt(stmt_i, &stmts)?
         }
@@ -48,6 +50,10 @@ impl InterpretCtx {
                 let value = self.read_value(from);
                 self.write_place(to, value);
             }
+            Stmt::Movb { from, to } => {
+                let value = self.read_byte_value(from);
+                self.write_byte_place(to, value);
+            }
             Stmt::Add { to, value } => {
                 let old = self.read_place(to);
                 let value = self.read_value(value);
@@ -96,8 +102,17 @@ impl InterpretCtx {
 
     fn interrupt(&mut self, number: u64) {
         match number {
-            0 => todo!("exit"),
-            1 => todo!("print"),
+            0 => {
+                let code = self.reg(Register(0));
+                std::process::exit(code as i32);
+            }
+            1 => {
+                let str_addr = self.reg_addr(Register(0));
+                let str_len = self.reg_addr(Register(1));
+                let slice = &self.memory[str_addr..][..str_len];
+                let is_ok = std::io::stdout().lock().write_all(slice).is_ok();
+                *self.reg_mut(Register(0)) = if is_ok { 0 } else { 1 };
+            }
             _ => panic!("invalid interrupt!"),
         }
     }
@@ -109,11 +124,18 @@ impl InterpretCtx {
         }
     }
 
+    fn read_byte_value(&self, value: &Value) -> u8 {
+        match value {
+            Value::Literal(n) => *n as u8,
+            Value::Place(place) => self.read_byte_place(place),
+        }
+    }
+
     fn read_place(&self, place: &Place) -> u64 {
         match place {
-            Place::Register(reg) => self.registers[reg.as_index()],
+            Place::Register(reg) => self.reg(*reg),
             Place::AddrRegister(reg) => {
-                let addr = self.registers[reg.as_index()] as usize;
+                let addr = self.reg_addr(*reg);
                 self.read_addr(addr)
             }
             Place::AddrLiteral(addr) => {
@@ -123,14 +145,27 @@ impl InterpretCtx {
         }
     }
 
+    fn read_byte_place(&self, place: &Place) -> u8 {
+        match place {
+            Place::Register(reg) => self.reg(*reg) as u8,
+            Place::AddrRegister(reg) => {
+                let addr = self.reg_addr(*reg);
+                self.memory[addr]
+            }
+            Place::AddrLiteral(addr) => {
+                let addr = *addr as usize;
+                self.memory[addr]
+            }
+        }
+    }
+
     fn write_place(&mut self, place: &Place, value: u64) {
         match place {
             Place::Register(reg) => {
-                let r = &mut self.registers[reg.as_index()];
-                *r = value;
+                *self.reg_mut(*reg) = value;
             }
             Place::AddrRegister(reg) => {
-                let addr = self.registers[reg.as_index()] as usize;
+                let addr = self.reg_addr(*reg);
                 self.write_addr(addr, value);
             }
             Place::AddrLiteral(addr) => {
@@ -140,6 +175,22 @@ impl InterpretCtx {
         }
     }
 
+    fn write_byte_place(&mut self, place: &Place, value: u8) {
+        match place {
+            Place::Register(reg) => {
+                *self.reg_mut(*reg) = value.into();
+            }
+            Place::AddrRegister(reg) => {
+                let addr = self.reg_addr(*reg);
+                self.memory[addr] = value;
+            }
+            Place::AddrLiteral(addr) => {
+                let addr = *addr as usize;
+                self.memory[addr] = value;
+            }
+        }
+    }
+
     fn read_addr(&self, addr: usize) -> u64 {
         u64::from_le_bytes([
             self.memory[addr],
@@ -160,6 +211,18 @@ impl InterpretCtx {
             self.memory[addr + i] = bytes[i];
         }
     }
+
+    fn reg(&self, reg: Register) -> u64 {
+        self.registers[reg.as_index()]
+    }
+
+    fn reg_mut(&mut self, reg: Register) -> &mut u64 {
+        &mut self.registers[reg.as_index()]
+    }
+
+    fn reg_addr(&self, reg: Register) -> usize {
+        self.reg(reg) as usize
+    }
 }
 
 pub fn interpret(stmts: Vec<Stmt>, _spans: Vec<Span>) -> Result<()> {

src/ir.rs

@@ -35,6 +35,7 @@ pub struct Location {
 #[derive(Debug, Clone, Copy, DebugPls)]
 pub enum Stmt {
     Mov { to: Place, from: Value },
+    Movb { to: Place, from: Value },
     Add { to: Place, value: Value },
     Sub { to: Place, value: Value },
     Mul { to: Place, value: Value },
@@ -75,6 +76,11 @@ impl CompileCtx {
                 let to = self.compile_place(to)?;
                 Stmt::Mov { from, to }
             }
+            StmtKind::Movb { from, to } => {
+                let from = self.compile_value(from)?;
+                let to = self.compile_place(to)?;
+                Stmt::Movb { from, to }
+            }
             StmtKind::Add { to, value } => {
                 let to = self.compile_place(to)?;
                 let value = self.compile_value(value)?;
@@ -97,10 +103,13 @@ impl CompileCtx {
             }
             StmtKind::Int { number } => {
                 if number > 1 {
-                    return Err(CompilerError::simple("invalid interrupt".to_string(), p_stmt.span));
+                    return Err(CompilerError::simple(
+                        "invalid interrupt".to_string(),
+                        p_stmt.span,
+                    ));
                 }
                 Stmt::Int { number }
-            },
+            }
             StmtKind::Jmp { to } => {
                 let to = self.compile_location(to, self.stmts.len())?;
                 Stmt::Jmp { to }

src/parser.rs

@@ -9,6 +9,8 @@ use crate::error::{CompilerError, Result};
 pub enum Token<'a> {
     #[token("mov")]
     Mov,
+    #[token("movb")]
+    Movb,
     #[token("jmp")]
     Jmp,
     #[token("je")]
@@ -63,6 +65,7 @@ impl DebugPls for Stmt {
 #[derive(Debug, PartialEq, Eq, DebugPls)]
 pub enum StmtKind {
     Mov { to: Expr, from: Expr },
+    Movb { to: Expr, from: Expr },
     Add { to: Expr, value: Expr },
     Sub { to: Expr, value: Expr },
     Mul { to: Expr, value: Expr },
@@ -160,6 +163,12 @@ where
                 let from = self.expr()?;
                 stmt(span.start..from.span.end, StmtKind::Mov { to, from })
             }
+            Token::Movb => {
+                let to = self.expr()?;
+                expect!(self, Token::Comma);
+                let from = self.expr()?;
+                stmt(span.start..from.span.end, StmtKind::Movb { to, from })
+            }
             Token::Jmp => {
                 let to = self.expr()?;
                 stmt(span.start..to.span.end, StmtKind::Jmp { to })
@@ -260,6 +269,7 @@ where
                 expr(ExprKind::Symbol(name.to_owned()), span)
             }
             Token::Mov => return Err(CompilerError::not_allowed(span, "mov")),
+            Token::Movb => return Err(CompilerError::not_allowed(span, "movb")),
             Token::Jmp => return Err(CompilerError::not_allowed(span, "jmp")),
             Token::Je => return Err(CompilerError::not_allowed(span, "je")),
             Token::Cmp => return Err(CompilerError::not_allowed(span, "cmp")),

test.at

@@ -1,14 +1,7 @@
-mov r0, 3
-cmp r0, 8
-je true
-jmp false
-true:
-jmp exit
-
-// loop
-false:
-mov r5, [8]
-jmp false
-
-
-exit:
+mov [0], 40
+mov [1], 41
+mov [2], 42
+mov [3], 43
+mov r0, 0
+mov r1, 4
+int 1